# Increasing Water Hardness Recipe



## dwalstad (Apr 14, 2006)

Recently, I increased water hardness in my tanks with growing guppies, plants, and molting shrimp. This is because the well water I use went from a GH of 10-17, when I last measured it back around 1991 and 2007, to a too-low GH of 3. The decrease was due to continuous rainfall last few years. I followed the basic ideas in my book (p. 87). Goal was to increase water hardness in my tanks by adding key nutrients Ca, Mg, and K in as easy a manner as possible. This recipe won't increase pH (no carbonate salts) and it avoids loading up tank with sulfates by using commercial products (all the Ca, K, Mg come as sulfate salts).

I prepared (or had on hand) two key stock solutions.

Calcium: One is a CaCl2 (calcium chloride) solution. Mine was a saturated solution in an ancient bottle from a lab giveaway that I have kept for 20 years (photo). All CaCl2 preparations-barring those kept in a lab dessicator or lab oven--usually come with attached water molecules, plus CaCl2 quickly forms a liquid. So you can't really measure out crystals or liquids of CaCl2 accurately and assume you have added so much of the actual Ca. Measuring the effect that a CaCl2 addition has on GH is the best and most accurate way to measure how much Ca you are adding.

I added 5 ml (about one teaspoon) of the CaCl2 liquid (from brown bottle in photograph) to my 20 gal (80 liter tank). Starting GH was 4 and the addition increased it to 8, so the addition increased the GH by 4. This result with a 1:16,000 dilution was very acceptable. Done!

Magnesium: MgSO4 was from Epsom salts I bought at drug store (photo). Crystals came with some added fragrances, but otherwise its mostly MgSO4. Like CaCl2, MgSO4 comes with attached water molecules and gradually absorbs water, so you have to measure its effect on GH.

To prepare stock solution, I added 2 Tablespoons (~36 grams) of the Epsom salts to 2 cups (~500 ml) of tapwater. I had no idea how much this would increase GH, so I tested it by adding 1 ml to a quart of tapwater (~1 liter or 1,000 ml). GH increased from 3 to 5, so I knew that a 1:1,000 dilution would increase GH by 2 solely due to Mg.

Potassium: I purchased KCl from grocery store as a "salt substitute." I added 2 teaspoons (~12 g) to the Mg stock solution I prepared earlier. Fortunately, it did not form a precipitate. Thus, I could add Mg and K at the same time from this Mg/K stock solution.

I decided that my tank would do fine with a:1:16,000 dilution of each of my two stock solutions (Ca and Mg/K) in the tank water. (The main thing was getting enough calcium into the water.) To get a 1:16,000 dilution, I add 5 ml (~1 tsp) of each stock solution to 20 gal (80 liter) of tank water. 80 liters divided by 5 ml = 16,000. For a 10 gal tank, I'll add 2.5 ml of each stock solution, the same 1:16,000 dilution. When I change water I'll just add some of each stock solution. It doesn't have to be that accurate and doubling or tripling the 1:16,000 dilution "dose" that I add should not cause any problems.

In my experience, adding shells (CaCO3) to increase GH hasn't helped that much or worked fast enough. For example, I added 1 tsp of oyster grit to a 1 gal shrimp bowl and a month later GH had not increased above the starting GH of 3. If you use shells, please actually measure the GH in tank water to make sure that they are working.


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## mistergreen (Mar 3, 2007)

Yup, I have a bag of CaCl2 & MgCl2. They've absorbed the humidity and now solid and almost slushy. You can get MgCl2 off amazon. It's used to make Tofu.


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## aquabillpers (Apr 13, 2006)

Is it possible that your well is getting groud water infiltration? is the water even slighy turbid? Mine is 150 feet deep and the chemustry never changed, regardless of rainfall.


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## dwalstad (Apr 14, 2006)

aquabillpers said:


> Is it possible that your well is getting ground water infiltration? is the water even slightly turbid? Mine is 150 feet deep and the chemistry never changed, regardless of rainfall.


I'm *sure* there's surface water infiltration. Water gets turbid every once in awhile. When I moved onto my wooded 4 acres 33 years ago, there was an old dog house over the well head. I replaced it *myself* with a little structure using concrete blocks for the sides and fiberglass panels for the top. But I never added the recommended concrete platform covering the surrounding soil, because I just hate mixing concrete!

Had a good laugh about MgCl2 used for making Tofu.


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## aquabillpers (Apr 13, 2006)

I once lived in an old house that started as a spring house in the 18'th centory. Over time more house was built around the spring until the house became something like a 3 bedroom cape co. The original spring still served as the water supply, and its outflow flowed through a channel in the basement.

Sculpins bred under rocks in the basement and elodea and water cress grew copiously outside. It was quite nice.

The spring was polluted with surface water. A chlorinater metered a tiny amout of Clorox into the water as it was drawn. We detected no taste in the water and no one got ill from it.

But when one drank from the spring outside the house, he - only guys did this <g> - was guaranteed to have an upset stomach the next day, but the cold water was so tasty on a hot day that it was worth it!

This was in a somewhat developed area, not a large wooded lot, but it is risky to drink surface water anywhere. Birds and animals, living and dead, can leave debris on land surfaces that wash into drinking water supplies and cause illness. One should not drink surface water. My opinion, of course.

Bill


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## mistergreen (Mar 3, 2007)

dwalstad said:


> because I just hate mixing concrete!


Is it weird that I love mixing concrete?


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## Michael (Jul 20, 2010)

mistergreen said:


> Is it weird that I love mixing concrete?


Yes! it is back-breaking work! Next time we have a project, will you come to our house?


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## hoppycalif (Apr 7, 2005)

mistergreen said:


> Is it weird that I love mixing concrete?


Yes, they have pills for that now.


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## mistergreen (Mar 3, 2007)

I mix concrete in a wheel barrel, saves the back. I had to reseal a leaky toilet the other day. It’s impossible to lift that thing without straining your back.


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## SamXp (Mar 12, 2020)

Thanks for sharing this. I added some Oyster grit to my canister filter and hoping it does the trick because I’m not excited about playing chemist. 
I bought some CaCO3 in fine powder “food grade” form and cannot get it to dissolve in water. Added barely a teaspoon to 36gallons, ended up with cloudy water and GH didn’t budge. 
Guess I need to try CaCl


Sent from my iPhone using Tapatalk


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## FlatfishTanker1 (Mar 13, 2020)

I wanted to share this about water hardness as it relates to fish. I was concerned about my "off the charts" hard water here in San Diego from my well. So I asked Dan from Dan's Fish. This is what he said:

_"Thanks for the email. The good news is that soft water fish adapt almost instantly to hard water...it is going from hard water to soft that there are issues, so your hard water is actually a blessing. The only time hard water is detrimental is if you are actually trying to breed the fish. Several soft water species have eggs that don't develop well in hard water...lots do, but, if breeding blackwater species is the goal, then an RO unit might be in order. If breeding is not the goal, then hard water is actually your friend."_

Harder water is good for most plants because of the increased minerals and nutrients. I was concerned about my water being too hard for many fish. Dan's answer to my concern has eased my mind about my hard water quite a bit. I wonder if plants have a similar adaptation ability that fish do. In other words, _do soft water plants adapt to hard water easier than hard water plants adapt to soft water?_


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## hoppycalif (Apr 7, 2005)

Not too many years ago we believed that softer water was ideal for many plants, but it looks like this might have been another of the myths that we all blindly accepted. I have no idea whether it is a myth or a fact, but I do find it very interesting. It is another opportunity for some of us amateur scientists to do some experimenting.


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## Red_Rose (Mar 18, 2007)

hoppycalif said:


> Not too many years ago we believed that softer water was ideal for many plants, but it looks like this might have been another of the myths that we all blindly accepted. I have no idea whether it is a myth or a fact, but I do find it very interesting. It is another opportunity for some of us amateur scientists to do some experimenting.


When I first started my research into Walstad tanks, my water hardness was my main concern. Our city's tap water is very hard at 28(the area I live in is the highest) with an equally high KH. I thought my water would be too hard for this type of setup that I tried softening water in an empty small tank. I did a 50-50 of tap water and distilled water and my hardness didn't budge. lol

I've recently gotten some shrimp and I've always had a ton of snails in my tank so now I'm thankful that my water is hard because those little guys do better with it.


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## dwalstad (Apr 14, 2006)

FlatfishTanker1 said:


> In other words, _do soft water plants adapt to hard water easier than hard water plants adapt to soft water?_


It's not a question of adaptation but getting nutrients plants need for the synthesis of their proteins, DNA, Ca channels, etc.

Hardwater nutrients (Ca,Mg, K, S, etc) are essential for life, plants and fish. Softwater plants come from softwater habitats because they have adapted to an environmental niche where they they can survive better than "hardwater" plants. It gives them a competitive edge. Softwater plants are more adept than hardwater plants in sifting these nutrients out of the water. When softwater plants are transported to hardwater, they are in heaven. Now they finally can get these vital nutrients in abundance. (See p. 117 in my book for my experiment on getting a much greater yield growing softwater plants in hardwater.)

The reverse--transferring hardwater plants to a softwater tank--is a disaster. Now these plants are in an environment that contains none of the vital nutrients (Ca, Mg, K, S, etc) that they need. Plus, hardwater plants don't have the ability of softwater plants to sift these nutrients efficiently out of the water.

Decades ago, I couldn't understand how Arizona Aquatic Gardens and Florida aquatic plant nurseries (working with superhard water) could grow aquarium plants to sell. I too bought into the myth that softwater plants need softwater. Now, I understand.


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## hoppycalif (Apr 7, 2005)

Doesn't the pH have to be below 7.0 for carbonates to dissolve? If your water pH is 5.6 and too soft, adding CaCo3 would both raise the pH and the GH. This is just an intuitive opinion.


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## Regis (Jun 26, 2020)

Diana, thank you so much for the recipe. I live in Portland, Oregon, and our water is very soft. this recipe will come in handy 
What is your opinion on use baking soda or crushed coral to increase hardness?


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## Regis (Jun 26, 2020)

Well... I should have checked your book before posting my question above :doh:
The text on pages 86 and 87 answered it


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## imgaurav86 (May 1, 2020)

Hi everyone,
This is my first post in this forum. English is not my first language so I apologize if you have difficulty understanding.
This is my second attempt on nano Walstad tank. I live in Melbourne, Australia and water here is very soft. According to the Melbourne waters website it has *GH of 10-18 milligrams per litre*. *Calcium is 3.0-5.0 ml/L Magnesium 1.0 -1.5 ml/L*. Water analysis report Area Silvan.

I am trying to make stock solution to increase water hardness. I am bit lost with the calculations and don't have GH test kit. I have purchased 100% pure KCL food grade, 100% Magnesium Sulphate (Epsom Salt), Calcium Chloride (Damprid) Found this from a forum, people using it in reef tank. According to the forum 250 grams Calcium chloride (damprid) makes 3 liter of stock with 14,700 ppm of calcium (Forum Link) Datasheet.

Is it possible to figure out how much of each I use to create stock solution and how much stock solution I can use in 40 liter tank.

Thanks


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## mistergreen (Mar 3, 2007)

imgaurav86 said:


> Is it possible to figure out how much of each I use to create stock solution and how much stock solution I can use in 40 liter tank.
> 
> Thanks


This calculator will help figure out the numbers
https://rotalabutterfly.com/nutrient-calculator.php


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## Phatboyaa (Jun 15, 2020)

I'm sorry if this is not directly related to the topic. Recently I've noticed that my bladder snail's shell is hanging high from it's body and some of them is visibly deteriorating (pic attached). Do you guys think it's because of lack of GH and KH in my water?


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## hoppycalif (Apr 7, 2005)

imgaurav86 said:


> Hi everyone,
> This is my first post in this forum. English is not my first language so I apologize if you have difficulty understanding.


 Welcome to APC!

Your English is very good and easy to understand.


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## Hollow6 (Nov 5, 2019)

Testing water hardness has been a pain for me. Where I live those tests made for aquarium are imprecise and sometimes doesn't even work.

I know for a fact that my water is soft but I haven't had much issues in my first tank so far because it was made for only one betta and I used only fast growing/not demanding plants.

I'm going to build a new tank and I'm afraid that my GH may ruin it. I will try to use a test kit made for swimming pools, they seem to be more precise than aquarium ones.


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## hoppycalif (Apr 7, 2005)

Hollow6 said:


> Testing water hardness has been a pain for me. Where I live those tests made for aquarium are imprecise and sometimes doesn't even work.
> 
> I know for a fact that my water is soft but I haven't had much issues in my first tank so far because it was made for only one betta and I used only fast growing/not demanding plants.
> 
> I'm going to build a new tank and I'm afraid that my GH may ruin it. I will try to use a test kit made for swimming pools, they seem to be more precise than aquarium ones.


I don't know where you live, but can you order things from places like Amazon? Look for a GH test kit, not a KH.


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## Karen in San Jose (Jun 1, 2020)

Hollow6 said:


> Testing water hardness has been a pain for me. Where I live those tests made for aquarium are imprecise and sometimes doesn't even work.
> 
> I know for a fact that my water is soft but I haven't had much issues in my first tank so far because it was made for only one betta and I used only fast growing/not demanding plants.
> 
> I'm going to build a new tank and I'm afraid that my GH may ruin it. I will try to use a test kit made for swimming pools, they seem to be more precise than aquarium ones.


If it's municipal water, you can usually get test results from them, too.


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## dwalstad (Apr 14, 2006)

imgaurav86 said:


> Is it possible to figure out how much of each I use to create stock solution and how much stock solution I can use in 40 liter tank.


The recipe for preparing stock solutions is my first post on this thread. If you've got just one tank, you may not need a stock solution. Here's what I'd try if I just had one tank:

I calculated dosage for a 40 liter tank and came up with 1/4 tsp (1,500 g) of "wet" calcium chloride (CaCl2∙H2O). Since CaCl2∙H2O is only 28% pure calcium, you are adding 422 mg of pure Ca. 422 divided by 40 liters = 10 ppm Ca. That's close enough.

I would just add a ¼ tsp of KCl and a pinch of MgSO4 and call it a day. Calcium is the most important nutrient.

Be sure to mix up each ingredient *separately* in a little water before adding to the tank. You don't want your fish eating pellets of CaCl2!

Thanks for sending all the details. I looked at Melbourne, Australia water quality. Interesting. Parameters look similar to New York City water. Nice water but very soft.


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## Phatboyaa (Jun 15, 2020)

Ms. Walstad I'd like to know your opinion about Seachem Replenish. Their older product, Equilibrium, consist of sulphate salts that would be harmful to the tanks because they convert to H2S. This Replenish product is made all using Cl salts, do you think it's okay to use them? I'd like to prepare my own solution but there are no chemical supply store where I lived. Had to order them online and the shipping is quite unreasonable.


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## dwalstad (Apr 14, 2006)

This product, which I did not know about until you wrote, looks like a good and easy way to increase water hardness. Based on the product reviews and my own bias towards chloride as a safer anion, I would go with it. If you get bad results, please let us know.

Thank you so much for bringing this to my attention!


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## Phatboyaa (Jun 15, 2020)

dwalstad said:


> This product, which I did not know about until you wrote, looks like a good and easy way to increase water hardness. Based on the product reviews and my own bias towards chloride as a safer anion, I would go with it. If you get bad results, please let us know.
> 
> Thank you so much for bringing this to my attention!


You're welcome Ms. Walstad. My Seachem Replenish is arrived today. Added some to my tank and accidentally put too much. Meant to Increase my GH from 3 to 8 and ends up increasing it to 13. I'll let you updated about the results.


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## jatcar95 (Oct 30, 2019)

I looked into replenish a bit, because I currently use equilibrium to raise my hardness. According to seachem, replenish isn't made for planted tanks and they warn that it "contains higher levels of sodium and chloride that may be stressful to plants". https://www.seachem.com/support/forums/forum/general-discussion/22045-equilibrium-or-replenish

I don't know much of the science behind water hardness, could someone explain why sulphate salts would be more/less harmful than sodium and chloride?


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## dwalstad (Apr 14, 2006)

You have a point. It seems Replenish is not designed for planted tanks. Na isn't the problem, it just doesn't have enough K and Mg.

Looking at the product ingredients, it has 13% Ca, 1% Mg, 0.12% K, and 0.6% Na.

We know that 100 ppm NaCl (which is 40 ppm Na), inhibits plants. Let's say you add enough Replenish to get hard water with 13 ppm Ca. That means you'll have added only 0.6 ppm Na. That 0.6 ppm Na is not much compared to 40 ppm Na and should not inhibit plants

Replenish only contains 0.12% K. If you add 13 ppm Ca, you're only adding 0.12 ppm K. That's probably not enough *and *K is a major nutrient.

Same problem with Mg.

Anyway, I thought Replenish would be an easy softwater fix, but I was wrong. I'll go back to my own homemade recipe as being better than either Replenish or Equilibrium. My book has the recipe (p. 87).


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## dwalstad (Apr 14, 2006)

jatcar95 said:


> I don't know much of the science behind water hardness, could someone explain why sulphate salts would be more/less harmful than sodium and chloride?


Good question. A little sulfate is fine AND sulfur (S) is a major nutrient. However, too much sulfate in the water can cause problems in a tank containing an organic soil underlayer. Most potting soils and other organic soils become quite anaerobic when submerged. If there's a lot of sulfates in the water, they will percolate into the soil layer. Sulfate-reducing bacteria (my book, p. 67) will convert these sulfates into H2S (hydrogen sulfide). This smelly gas kills plant roots, inhibits plant growth, and may even harm bottom-dwelling fish. H2S is more toxic than ammonia.

Chloride is not toxic and presents no such problems. (This has been discussed thoroughly in another thread.)

If you look at the Equilibrium product, it is made *solely* from the sulfate salts of Ca, Mg, K, Fe, and Mn as in CaSO4, K2SO4, MgSO4, etc. That means when you add Equilibrium, you are adding a TON of sulfates. This product may work in gravel or sand tanks or ones with a mineral type soil, but not ones with an organic soil underlayer.


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## jatcar95 (Oct 30, 2019)

Thanks for the thorough explanation! I have very soft water here in the PNW, so I will have to try out your recipe.


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## Phatboyaa (Jun 15, 2020)

dwalstad said:


> You have a point. It seems Replenish is not designed for planted tanks. Na isn't the problem, it just doesn't have enough K and Mg.
> 
> Looking at the product ingredients, it has 13% Ca, 1% Mg, 0.12% K, and 0.6% Na.
> 
> ...


Oh well that's a bummer! But I guess considering my position a little bit of Replenish is better than nothing. From what you're saying K and Mg is quite an Important element for plant. What's the sign that my plants lack any of them?


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## jatcar95 (Oct 30, 2019)

I am putting together the ingredients for the water hardness recipe in the book. Found epsom salts no problem, and of course baking soda is pretty easy to come by.

For KCl, I found salt substitute at the store, but it looked like it had other additives as well. Ingredient list attached, does this seem like it would be okay to add, or should I find a more pure variety?

For CaCl2, I went to a couple places, but apparently most people aren't looking for de-icer in the summer. Is the best way to get this to order online? Is there some specialty store that might carry it?

Thanks!


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## hoppycalif (Apr 7, 2005)

You can buy those chemicals on Amazon, of all places. The prices might not be what you want, but they seem to have everything.


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## jatcar95 (Oct 30, 2019)

Thanks for the suggestion @hoppycalif. I actually found a local brewer who carries calcium chloride - apparently it's also used for making beer!

How about the salt substitute? Do those other ingredients seem worrisome?


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## dwalstad (Apr 14, 2006)

I don't think that any of the minor ingredients listed for the 'Salt Substitute' would cause a problem.


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## jongalong (Aug 10, 2020)

jatcar95 said:


> I am putting together the ingredients for the water hardness recipe in the book. Found epsom salts no problem, and of course baking soda is pretty easy to come by.
> 
> For KCl, I found salt substitute at the store, but it looked like it had other additives as well. Ingredient list attached, does this seem like it would be okay to add, or should I find a more pure variety?
> 
> ...


Hey Jatcar95,

I'm up the coast from you in Seattle and figuring out my dosing as well to harden up the water for my tanks. What did you end up doing and how did you measure out the dry ingredients? Did you end up with a recipe you are happy with?

I have the same nosalt for KCl, and a bag of MgCl and a bag if CaCl. I tried the recipe to harden with Mg and Ca and it worked surprisingly well, I got my GH to 8 (from less than 1) on the first crack, but it was just by pouring some into an API test tube, and eyeballing the level in the tube before combining with water.

Not the most precise method.

I'd love to hear if you made up solutions and if so how you measured it out.


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## jongalong (Aug 10, 2020)

It just occurred to me that it doesn't matter what the source is - I need to mix an arbitrarily concentrated solution of each, and calibrate how much of each solution will raise the GH according to the 4:1 ratio, and then dose based on that, so I'll have my own custom concentrated solutions and my dosing calibrated to whatever random concentration mine are.

So, I guess, nevermind on that!

Page 87 gives me all I need, I just need to pick a concentration and calibrate to that and I'm good.


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## jatcar95 (Oct 30, 2019)

jongalong said:


> Hey Jatcar95,
> 
> I'm up the coast from you in Seattle and figuring out my dosing as well to harden up the water for my tanks. What did you end up doing and how did you measure out the dry ingredients? Did you end up with a recipe you are happy with?
> 
> ...


Just moved down from Seattle myself!
Very similar water to Portland, it seems. I ended up calculating the ratios of each chemical as tablespoons per gallon (easy measurements I had laying around, not super scientific), and mixed up a solution that way. I have all the calculations sitting somewhere, I will see if I can dig it up.

I did have one mishap where I confused using a specific amount of the diluted solution vs using the pure chemical, and briefly had a saltwater tank. Oops! Did a 100% water change and retried, everything turned out fine (only had plants + snails + blackworms at the time).

I planned on mixing together all the chemicals in a single jar, so next time the measurements would be easier. Never got around to it though, as I only needed to raise the hardness that first time.


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## jatcar95 (Oct 30, 2019)

@jongalong yes, it's all about the ratios. I actually used teaspoons instead of tablespoons. Here was the summary I came up with. Note the first three involve distilling into a solution, then mixing some of that into the tank. The last two I didn't do the distillation first (just mixed the correct amount for my 6.5 gallon with an arbitrary amount of tank water, then poured it back in). 

Calcium:
Mix 3 tsp CaCl2 with 1 cup water. Dose 1 tsp of this solution per gallon.

Magnesium:
1 tsp MgSO4 with 2 cups water, dose 1 tsp of this solution per gallon.

Potassium:
Dose 1/8 tsp of KCl per 10 gallons of water.

Bicarbonate:
Dose 1 tsp baking soda per 10 gallons water.

Please double check the calculations, but I hope this makes it a bit simpler  I think I still did some tweaking at each level to get the exact hardness I wanted. Went through quite a few vials of tests that night!


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## dwalstad (Apr 14, 2006)

jatcar95 said:


> I planned on mixing together all the chemicals in a single jar, so next time the measurements would be easier. Never got around to it though, as I only needed to raise the hardness that first time.


If you mix the chemicals, you may get a white precipitate (solid particles) that is essentially useless or impossible to work with or measure or go into solution.

[I suspect that water-hardening commercial products are formulated for ease of use by hobbyists, and why SeaChem's 'Equilibrium' is all sulfate salts. The vendors have mixed Ca, Mg, K, etc salts that won't precipitate "on the shelf." I actually spoke with SeaChem's sales representatives (very nice people) decades ago about making an Equilibrium-like product with less sulfates, but nothing came of it.]

That said, I'm glad that you got what you wanted. Very good....


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## jatcar95 (Oct 30, 2019)

dwalstad said:


> If you mix the chemicals, you may get a white precipitate (solid particles) that is essentially useless or impossible to work with or measure or go into solution.


Should have known it wouldn't be that simple  I will keep them separate then, easy enough to measure each one out given how infrequently I have to use them. Thanks for the heads up!


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## jongalong (Aug 10, 2020)

jatcar95 said:


> @jongalong yes, it's all about the ratios. I actually used teaspoons instead of tablespoons. Here was the summary I came up with. Note the first three involve distilling into a solution, then mixing some of that into the tank. The last two I didn't do the distillation first (just mixed the correct amount for my 6.5 gallon with an arbitrary amount of tank water, then poured it back in).
> 
> Calcium:
> Mix 3 tsp CaCl2 with 1 cup water. Dose 1 tsp of this solution per gallon.
> ...


Awesome! Thank you!

I ended up mixing up two solutions of MgCl and CaCl, and using the procedure outlined to get a Mg/Ca GH bump, and it worked like.a charm. I have syringes around from a medical kit, and did it all in ml, also cause the math is easier!

I am going to do the same thing with bicarb to adjust the KH into the right range, and I think I ended up guessing at the KCl amount based on page 87 as well, and ended up with very close to what you did.

Thanks for sharing!

I ended up with 2 teaspoons of each of MgCl and CaCl in some old plastic ice cream containers (about 500ml each), then my recipe is 7ml of the MgCl and 10ml of the CaCl per 2000ml of tap water results in a GH of 9, most of which comes from the CaCl.

My tanks are all small 2.3 gallon specimens, and I'm excited to see how this changes my plant growth.

Anyway - thanks for sharing your notes!


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## dwalstad (Apr 14, 2006)

jongalong said:


> My tanks are all small 2.3 gallon specimens, and I'm excited to see how this changes my plant growth.


Thanks for your feedback.


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## jongalong (Aug 10, 2020)

dwalstad said:


> Thanks for your feedback.


As noted here, the hardening up of the water has had a tremendously positive effect!

Thanks for all the info in this thread, so great!


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## SudhirR (Apr 7, 2020)

Compared to calcium sulphate is calcium chloride more soluble? 

I have been using calcium sulphate dihydate in preparing my Gh booster along with Epsom
Salt and potassium sulphate

the solubility of calcium sulphate is very bad. 


Sent from my iPhone using Tapatalk


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## dwalstad (Apr 14, 2006)

Calcium chloride (CaCl2) is _very_ soluble. It goes into solution immediately, plus it will not change pH. CaSO4 (Calcium sulfate) is probably soluble as well.

CaCO3 (calcium carbonate) the component of shells, coral, and limestone is the compound that is not very soluble. And it will raise pH.

Your recipe using only sulfate salts of Ca, Mg, and K is not a good idea. You are adding too much sulfate. Sulfates build up in the water and percolate into substrate. Anaerobic bacteria in the substrate will convert sultates to the highly toxic gas H2S (my book, p. 67). H2S will kill/inhibit root growth and bottom-dwelling fish. Sulfates can cause major problems in substrates containing potting soil underlayers or even gravel substrates with anaerobic pockets of debris.

That is why I recommend CaCl2. The other compounds (e.g., MgSO4) are used in lesser amounts, so the minor sulfate addition is not as problematic.

A mesh bag of finely crushed coral or oyster grit in the filter would be my second choice.


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## GadgetGirl (Sep 25, 2013)

How often should KCl be added in El Natural tank?


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## dwalstad (Apr 14, 2006)

I don't have any rules on this. Amount needed will depend on plant growth, water changes, amount of fish food, etc. That said, there's lots of leeway.

I would add it once as I described to "harden up" softwater--along with Ca and Mg-- or whenever you see deficiency symptoms.


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## GadgetGirl (Sep 25, 2013)

I've been adding baking soda (discussed here: https://r.tapatalk.com/shareLink/to...3&share_fid=7966&share_type=t&link_source=app).

My tank has a Saf-t-sorb cap which lowers ph & kH. Well, after a few days of adding 1/4 tsp bicarb a day, the pH has gone from <= 5 to 7.6. KH has gone from 0 to 2. My question is, do I keep adding bicarb to raise kH more or will this raise pH too much? (GH is 8.)


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## dwalstad (Apr 14, 2006)

I wouldn't add any more baking soda. You don't want to inhibit plant growth with excess sodium--unnecessarily. Your KH and pH are acceptable.


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## GadgetGirl (Sep 25, 2013)

Thank you ...I will just continue to monitor.


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## Greenmeanie (Oct 16, 2020)

First post here. While I wait for my dry start to develop I have purchased some items to harden my water as the gh is one and the kh is 11. Following the recipe discussed here and the information on page 87 of the Walsted method I have some salt substitute made by Windsor. Ingredients consist of potassium chloride,calcium silicate,magnesium carbonate,sugar and finally potassium iodide.


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## Greenmeanie (Oct 16, 2020)

I forgot the question. Does anyone see any deleterious issues using this.


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## GadgetGirl (Sep 25, 2013)

Greenmeanie said:


> I forgot the question. Does anyone see any deleterious issues using this.


If the other ingredients concern you, Amazon has pure potassium chloride. This is what I use:
https://www.amazon.com/dp/B07PGCMHS4/ref=cm_sw_r_cp_apa_i_vAHIFbMSQ1F3X


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## Greenmeanie (Oct 16, 2020)

Thank you Gadget Girl for the link.I am hoping Ms.Walstad will chime in and offer some guidance. If this product isn’t up to snuff I am certainly going to go with your recommendation. 😀


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## GadgetGirl (Sep 25, 2013)

Greenmeanie said:


> Thank you Gadget Girl for the link.I am hoping Ms.Walstad will chime in and offer some guidance. If this product isn't up to snuff I am certainly going to go with your recommendation.


Actually that one does have some magnesium carbonate in it, but I can't imagine that being detrimental. There are some pure forms on Amazon.


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## Greenmeanie (Oct 16, 2020)

Could you put a pic up of the stuff you use Gadget Girl. Just so I get the correct product if I have to. Thanks in advance.


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## GadgetGirl (Sep 25, 2013)

It's the one in the link.


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## Greenmeanie (Oct 16, 2020)

Thank you for the pic. In the link you provided I got the description but for some reason it wouldn’t provide the pic.I am not real techy but even my search wouldn’t bring it up. Thanks again for your help. 😀


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## dwalstad (Apr 14, 2006)

I don't see why it wouldn't work. 95% odds that it will work fine; 5% that it will not...

The main ingredient is KCl and I assume the minor ingredients like sugar would be present in only small amounts. None of them should cause a problem, chemically speaking.


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## Greenmeanie (Oct 16, 2020)

Thanks for your input Ms.Walstad.I bought your book a couple of years ago and am now into week 1 of the dry start. Your book is a treasure trove of information. I might just return this salt sub and purchase the item Gadgetgirl mentioned. Thanks again ladies for your help. 😀


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## dwalstad (Apr 14, 2006)

For correcting softwater deficiencies in tanks already set up, my recipe (using CaCl2, MgSO4, KCl chemicals) does not add bicarbonates. This may be a deficiency. If your KH is 3 or below after the Ca, Mg, and K additions, I would consider adding a little BS (baking soda). To increase KH by one degree, I see recommendations to add ¼ tsp BS to 13 gal or 1 gram BS to 10 gal. Sounds about right and dosage is flexible.


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## jatcar95 (Oct 30, 2019)

At least in my edition, it includes adding bicarbonates 


> For bicarbonate, I would add 1 tsp baking soda (NaHCO3) to each 10 gal of tank water.


 (pg 87)


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## dwalstad (Apr 14, 2006)

You gave me a good laugh! I seem to be repeating myself.


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## Scotmando (Jan 3, 2021)

I’ll be moving in March 2021 to a home just outside of town with well water and hopefully the water isn’t too soft. Great info on raising water hardness the right way. Thanks DWalstad and everyone for the great input and resources. I’ll let you know.


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## FarrisA (Sep 2, 2021)

To raise ph in a fish tank water using baking soda is one of the most effective ways. It is easy to do, economical, and cheap, does not need expertise, not that meticulous. Compared to other methods of raising ph in my fish tank, the use of baking soda is one of the cheapest and easiest for fish-keeping advocates.


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## dwalstad (Apr 14, 2006)

I would add that bicarbonates are not just a pH buffer. They are a carbon source for many submerged aquatic plants, especially those native to hardwaters and can use bicarbonates. One aquatic botanist (Craig S. Smith, 1993) showed two-fold faster growth of two aquatic plant species when bicarbonates were added to a nutrient solution.


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