# hard water softening



## mdurkin (Jun 3, 2008)

Hi All,
I already have an NPT that's about a year old now and going strong. I have naturally *very* hard water, giving a Ph of about 8.3. In my existing tank with normal topsoil and gravel, I've gradually lowered the Ph and hardness by mixing with RO water. The Ph is now about 7.3, and hardness much lower. This is completely stable, fish happy, plants stable, no algae whatsoever, good water parameters etc - the setup is a ~70 litre hex tank, and I occasionally do a 25% water change mainly to reduce the slight brown hue that slowly leeches from the soil.

I also have a nano (~40litres) tank (to be setup) and a larger tank (well as soon as I've persuaded the wife! This will be ~150 litres). I'm really pleased with my first tank, but I'd really like my dwarf cichlids to breed, and I think I'd need to soften up the water a fair bit more (they're happy but not breeding in my current setup).
Has anyone attempted this with success? I was wondering about a 50:50 topsoil peat mix for the substrate, coupled with a 50:50 mix of my very hard tapwater and RO water (to keep some natural nutrients for the plants).

I'd really appreciate anyone who's had a go at this with some success. In a perfect world I'd like to just use my tapwater, but I suspect that might not be possible.

Thanks,
Matt


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## dwalstad (Apr 14, 2006)

You're confusing pH with water hardness- a common error. You need to get a kit to measure Water Hardness. Then you can adjust your tapwater with R.O. water or other means until you get a GH of less than 4, which means softwater. See my book, p. 185. 

GH reflects the calcium & magnesium in hardwater. A high calcium/magnesium concentration can, indeed, hurt reproduction/egg hatching in softwater fish.


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## mdurkin (Jun 3, 2008)

Hi Diana,
I should have been more specific. My GH is about 180ppm and KH 240ppm. That happens to be the highest reading on the strips I have so I bought a chemical test kit which has a bigger range and I got the same results. The Ph is 8.3. I was assuming that the high Ph was related to the fact that the water is very hard.
In my existing tank I have, as you suggested, softened up the water by using RO. The GH and KH readings are 30 and 80 respectively (so still much higher than the 4 you mentioned), and the Ph has dropped to about 7.3. The plants are doing ok, though the crypts have had some thinning of the leaves (which have been removed) and I think perhaps nutrients are a bit lower than ideal as the plants have slowed down a bit now.

So using a RO local water mix worked well, but for dwarf Cichlids I believe I need to be looking to get the Ph below 7 (5.5-6 ideally). Or maybe as you suggest the water hardness is more important than Ph?
I have the smaller tank that I can use as a bit of an experiment, but I was hoping to hear from someone who's managed to successfully run a naturally planted aquarium with a slightly acid Ph, and ideas on how to achieve it.

Any ideas?
Thanks,
Matt
P.S. I have your book - I'll go re-read the page 185.


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## colinsk (Dec 29, 2008)

It sounds to me like you guys are using different units. 

Total Hardness in ppm = gH*17.9

Alkalinity in ppm = kH*17.9


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## Diana K (Dec 20, 2007)

GK of 30 ppm = 1.6 German degrees of hardness. This is very soft water, fine for the soft water fish, but might suggest that other minerals are also in short supply, and the plants may be experiencing some deficiencies. 

KH of 80 ppm = 4.5 German Degrees of Hardness. This is enough carbonates to keep the pH stable, but you may be able to lower the pH a bit by adding some peat moss to the filter. 

You can test this by trying perhaps 1/4 cup of peat moss in 5 gallons of water (use the same mix of RO + Tap that you are using in the tank). Test every few days for a week or so and see if this is doing for you what you want. If this is part of the answer you will need to prepare water change water ahead of time, with peat moss. 

Fish are looking for hard or soft water based on the GH test. Soft water is also water that usually has a very low TDS, or Total Dissolved Solids. Rain water, and RO water are like this. Hard water usually has lots of other minerals besides the calcium and magnesium measured by the GH test. The TDS of hard water is a lot higher. 
The GH is a measure of calcium and magnesium, which are plant fertilizers. If the GH reading is from a natural water source then some other minerals may be in the water as well, that are also plant nutrients. 

RO has no minerals (or so close to none that we can call it none). Mixing RO and tap water to get the balance you are looking for is a reasonable way to go, but you will not get away from it as long as you want this particular balance of GH, KH and pH. 

You might be able to add some fertilizer for certain plants, but keep the water the way the fish want it by adding some fertilizer tablets deep under the substrate, near the roots of the plants that need the fertilizer.


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## Alex123 (Jul 3, 2008)

I have very hard water in my tank, and most of my plants are hardwater variety. But in the future, if I decide to have softer water, I want a cheap way of making the water softer. Buying distilled water is out of the question. Having to worry about the right mix of tap and distill and dealing with evaporation, I think it will be expensive. I want it Cheap [email protected]@ it  Having hard water also tend to make my PH high as well. Using the distilled vinegar to lower PH is too short term and eventually PH goes up high again next day. Don't have well water around here so that's out of question. Rain water have pollution and acid ... so I don't think that's an option plus unreliable RO device are way expensive so that's out. I've even thought about building myself the survival drinking water setup where you put a plastic cover over water source and the evaporated water collects on plastic and go into a container. But seems like too much trouble and not effective in producing the quantity I want, not to mention long term effect of wet plastic. Ideas.


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## Diana K (Dec 20, 2007)

Having hard water is like having a bucket full of rocks. 
Having soft water is like having a bucket with a couple of pebbles in it. 

You cannot make that bucket full of rocks become a bucket with a few pebbles by ADDING anything to it. 

You need to REMOVE things from hard water if you want soft water. 

The most cost effective way to get soft water in any sort of volume is to get an RO unit for your house. You will need to decide which unit based on both the initial cost and the operating cost. 
Some of the cheaper units go through filter media way too fast, so the initial cheap purchase price is soon lost in filter media purchases. If you are dealing with a small tank, it may be better to just buy RO water in the stores. 
Some of the more expensive units have several levels of treatment, each of which is removing some things from the water. By the time the water gets to the actual RO membrane there is very little left, so the RO membrane lasts a long time. Each stage has a particular filter cartridge, and you will need to replace these over time. However, the with one of these multi-stage units you might not even actually need to go as far as the RO water to get water that is soft enough for the fish.

GH is General Hardness, a measure of Calcium and Magnesium. This is what the fish want when you see that you are dealing with a 'soft water' or 'hard water' fish. 
KH is Carbonate Hardness. Carbonates are one of the most common buffers in aquariums, that stabilize pH. 

High GH and high KH are often found together, but not always. Limestone, calcium and magnesium carbonate types of rocks will dissolve in rain water, and this water gets higher in GH and KH. Wells, rivers or lakes where the water has been in contact with this sort of rock is usually hard water. There are often other minerals in these rocks, too, that get dissolved in the water. 

pH can be stabilized by carbonates, and by other materials. When something acidic is added to water that is high in carbonates the carbonates remove the H+ ions from the water, and the pH does not drop. 
This is where people get confused:
They read pH. ~~This is what pH test is for: Is the water acidic or alkaline? How much H+ or OH- is in the water. 
They think 'Hard water'. ~~But the pH test does not test for water hardness. 
They think: ~~To soften the 'hard water' I will add acidic materials.

What happens is the carbonates (or other buffers) remove the acidic materials, and the pH does not change. 

Answer: THINK about what you REALLY want to do:
If your goal is softer water, from the fishes' point of view you want to remove calcium and magnesium from the water. Use the GH test to see what your treatment is doing, and monitor the KH and pH to check what side effects your treatment is having. You cannot ADD stuff, and have the result be the REMOVAL of stuff. Like that bucket of rocks. If you want fewer rocks in the bucket, you have to take out the rocks.

If your goal is to lower the pH, then you will start by lowering the KH level. Otherwise the KH will buffer the pH back to where it was. Use the KH and pH tests to see what effect your treatment is having, and monitor side effects with the GH test.
There are other materials that may be added to the water that make it show a high pH, but are not tested for with the KH or GH test. Often the water company will add something to the water to make it more alkaline, not so acidic because acidic water can damage the pipes. 
RO systems will remove these other materials, too.


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## bosmahe1 (May 14, 2005)

DianaK, nice explanation. Am I right in interpreting that fish don't realize or notice differences in PH or KH and that GH is the main concern?


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## flagg (Nov 29, 2004)

I think your current GH and KH readings are just fine, especially if you want to breed dwarf cichlids. The fry will need some hard water nutrients so mixing tap water with RO water will help.

I would however, advise not to get a RO unit as it is a waste of money and is unnecessary; you have access to soft water right outside your home: rain. Here at home we are breeding rams and bettas both of which require soft water with little to no hardness. What we've done is taken a new, clean garbage can and placed the end of a gutter downspout into it. Every time it rains, we have 35 gallons of soft water. We then take this water and just to be sure that nothing's leaching from the shingles (doubtful since the roof is old, more of a precaution) we filter it through a brita filter. Basically we fill up a 5 gal container (we get Poland Spring delivered so I've kept about a half dozen of their bottles) with rain water. Then, using small airline tubing the water is siphoned into the brita filter that sits in a funnel on top of another empty 5 gal bottle. We've finally gotten the flow just right so that the water just filters straight through. Whenever we're gonna make a water change we stick a heater into a bottle add some aeration and the next day it's ready to dump into our tank. Presto! No need for an expensive RO unit.

-ricardo


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## Diana K (Dec 20, 2007)

Actually, TDS, Total Dissolved Solids is the real number to test. But knowing what is in the water that is tested as TDS is important. 
Get the GH right, get the KH somewhere in the same neighborhood as the GH, and let the pH fall where it may. 

Collecting rain water is a very good way to get very soft water, if you are in an area with year round rain. 
There is no way I could store enough rain water to see me through a summer of water changes. I have been using all the rain that I collected as fast as I collected it.


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## brenmuk (Oct 7, 2008)

I use rain water (~70%) in my tank mixed with tap water (~30%) which is quite hard. If you are worried about pollution you can store the rain water in a tank or large container and run a filter with activated charcoal etc. I don't bother I actually think the rain water is cleaner than tap water even though I live in a city in the UK. Don't forget that acquatic plants remove alot of toxins from the water.
The only drawback in using rainwater over tap water is that it is pretty devoid of nutrients but these will be replenished in the tank from feeding and the soil etc.


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## Alex123 (Jul 3, 2008)

Rain water is a good idea. I don't want to pay for a RO equipment. I put more cover on my tanks. Now they are mostly covered. That should reduce water evaporation(recycle). I also trying the solar distillation idea. I have a aluminum container with plastic cover method. I put on the light hood vent. The heat should help evaporation in addition to sunlight. We'll see tomorrow how it goes.


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## colinsk (Dec 29, 2008)

Here is another idea, it is not used in fish keeping but works well in brewing. Since you only need to get a little lower, take 5 gallons of your tap water and add 1.4ml of 85% phosphoric acid and let it settle over night. Rack off the sediment. When you are done you will have removed about 50% of your calcium, about 25% of your magnisium and 90% of your alkalinity. There will be a lot of CO2 in solution so either agitate it or drip it slowly into the tank. You can generate enough disolved CO2 to corode metal so it would not be good for fish without degassing.

I use this method when recreating waters from famous brewing regions at work. The reaction for the calcium side is 2H3PO4+3Ca(HCO3)2>Ca3(PO4)2+6H20+6CO2. Some of the phosphates also become Magnisium Phosphate. The calcium phosphate precipitates and the magnisium phosphate precipitates about 50%.

Since I don't measure iron at work I don't know the equation or the pKs but this will likely precipitate the iron as well.


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## TAB (Feb 7, 2009)

peat works too, but it does stain the water and lowers the ph.

you can add it too teh tank, or make "peat water" and add to it.


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## dwalstad (Apr 14, 2006)

mdurkin said:


> Hi All,
> This will be ~150 litres). I'm really pleased with my first tank, but I'd really like my dwarf cichlids to breed, and I think I'd need to soften up the water a fair bit more (they're happy but not breeding in my current setup).
> Has anyone attempted this with success? I was wondering about a 50:50 topsoil peat mix for the substrate, coupled with a 50:50 mix of my very hard tapwater and RO water (to keep some natural nutrients for the plants).
> 
> Matt


Are these are softwater cichlids (e.g., _Apistogramma_, etc)? If so, I would suggest that next time you try the Tanganyikan dwarf cichilds. Fishkeeping is so much easier if the fish you keep match the water you have. 

That said, if you've got softwater cichlids, I think I have an easy solution.

I'd use a substrate that is mostly peat, maybe 90%. Mix in just a little (10%?) of your topsoil for the plants. The peat will pull calcium and magnesium out of the water and soften it. You can add peat to the filter as well.

Peat is nature's water softener. It exchanges calcium and magnesium for acid ions. Thus, it both softens water and brings the pH down.

Your question reminds that the water in my 45 gal with the potting soil (lots of peat in potting soil) was always softer than in the 50 gal with the pure clay garden soil. Whenever I measured salt content (TDS), the TDS in my 45 gal was always less than in the 50 gal. Plant growth was always better in the 45 gal, too.

Ordinarily, I wouldn't recommend a mainly peat substrate, but in your situation it might be just perfect.


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## drtechno (Mar 31, 2009)

May be you need to step back a little and think that you are creating the right conditions for breeding. I'm sure if you search the internet for the breeding conditions, they can be achieved.

1. temperature, water temperature is important more so than the water perameters.

2. are you providing the right spawning setting (i.e. a cave, slightly hidden with plants and a sandy bottom to dig a little) Too well lit of a setting might also be a factor.

3. some amazon/river fishes wait until after rainfall, to simulate this you need to take out a 1/3 of the tank's water then wait a week (let the toxins rise in the tank, then add distilled water, not r.o. water)

4. some species won't breed if there are fish in the tank that are not the same species. In one of my tanks, the rainbows refused to breed (some of them died because they got eqq bound) until I removed the cory cats, pea puffer, and the clown botias I had in the tank.


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## OldMan (Sep 22, 2007)

I must comment on the need for DISTILLED water. Although the TDS on RO water is a little higher than on distilled water, when you are making a mix of RO and tap, the extra 20 ppm of TDS in my RO is negligible when compared to the 325 ppm tap water that I am trying to lower. In essence, I can get anything between 20 ppm and 325 ppm by devising the right mix of tap and RO. When I want to drive even lower, can't think of why I would, I can collect rain water which measures less than 10 ppm TDS. The idea that I see in many places that distilled or RO will have a pH of 7.0 is misleading at best. RO has a pH that depends on what has been left behind as that 20 ppm. RO/DI is more like distilled and will give a much less predictable pH because anything, including air, that gets into the water will move the pH in whatever direction the impurity tends to move it. I work with nearly pure water in my industry and have seen water distillation and demineralizers both used to produce the almost pure water with TDS in the less than 1 ppm range. There is no way to tell the two waters apart that I am aware of but both methods produce very pure water that you do not want undiluted in your fish tank.


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## Hassles (Feb 15, 2008)

mdurkin said:


> Hi All,
> I already have an NPT that's about a year old now and going strong. I have naturally *very* hard water, giving a Ph of about 8.3. In my existing tank with normal topsoil and gravel, I've gradually lowered the Ph and hardness by mixing with RO water. The Ph is now about 7.3, and hardness much lower. This is completely stable, fish happy, plants stable, no algae whatsoever, good water parameters etc - the setup is a ~70 litre hex tank, and I occasionally do a 25% water change mainly to reduce the slight brown hue that slowly leeches from the soil.
> 
> I also have a nano (~40litres) tank (to be setup) and a larger tank (well as soon as I've persuaded the wife! This will be ~150 litres). I'm really pleased with my first tank, but I'd really like my dwarf cichlids to breed, and I think I'd need to soften up the water a fair bit more (they're happy but not breeding in my current setup).
> ...


For What Its Worth:

Breeding Dwarf Cichlids ? hmm, anything in particular you fancy ? I ask this because IF these dwarf cichlids happen to be Apistogramma, then you will find many that are not that fussy about water parameters providing the water is clean. Oh sure there does exist some Apistos that require near specific water parameters for sucessful breeding but many don't. The Apistogramma cacatouides immediately comes to mind.

I have also used Oak Tree Leaves to alter water parameters for some Apistogramma species. The Oak Tree leaves definitely lower PH and I suspect these also impact upon other water parameters but my tests are at this point inconclusive. More testing required.


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## Jane in Upton (Aug 10, 2005)

This may be an oddball suggestion, but if you have access to the charcoal colored Soilmaster Select, I've found that that also adsorbs GH and a lot of KH out of the water, significantly lowering the pH. I set up an El Natural style tank, using that as the top gravel layer, and for weeks I could not measure hardly ANY hardness, and the pH kept dropping. It was a problem, until finally about 6 weeks in, I'd added enough potassium bicarbonate (yeah, hard to find) that there was some buffering capacity and the pH stabilized. The tank has been great and amazingly stable ever since, but those first two months were doozies!

Ironically, the red colored Soilmaster (not 'Select') actually raises pH. 

I've done some testing on both types, since I had such extreme results with the red vs. the black, and I'll put than into a different thread. But, the overall result, doing side by side tests with a control, and two of each situation to be sure it wasn't a fluke, was that they really DO have very different effects on the water. 

My water comes out of the tap with high GH and KH (sorry measured numbers are in a folder downstairs), and a ph around 8.2 to 8.6 - I called the DPW, and he adds KOH to make the water alkaline. I recently set up a small tank with the red soilmaster, and its like rocks in there. I may just break it down and use the black stuff instead, since that seems to counter the natural hardness of the water out of the tap.

So, if you have any access to some, try a small bowl of it with your tap water to experiment, and possibly mix it into your substrate. I'm going to do some more in-depth testing and report back soon.

-Jane


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## Diana K (Dec 20, 2007)

I found Charcoal Soil Master Select would remove KH, but not GH. pH would drop.
Adding baking soda replaced the KH, but it did take 6 months or more until the SMS quit 'eating' the carbonates.


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