# Research...



## Grathum (Jul 13, 2010)

Hello all,

I was wondering if there were someone here with a good understanding of water chemistry that could help me out. I live in the minneapolis, mn area. I am currently researching the possiblity of setting up what will probably be termed as some kind of hybrid low tech/high tech tank because I plan to use CO2 injection and a small soil under layer. I want to use sand as the main substrate.

I want to setup a substrate for long-term success (i.e. I read about substrates getting "tired" or somehow wearing out). I have therefore been doing research on the water in my area to determine what I have and what I will need.

I was reading the yearly water report and I was struck by something that totally destroyed the notion I had of the relationship between PH and water hardness. My previous understanding was if you have a high Ph your water is probably hard. However, my water report says that minneapolis softens the water before sending it to customers. The PH of the water coming out of the tap is 8.75! Can someone please explain to me what process they may be using that would allow such a high PH but have soft water at the same time? I have searched and searched for information on the actual process but they do not detail what they are doing.

I have a small 5 gallon tank setup at the moment into which I am pumping Co2 but amazingly, I only need to send 1 bubble every 14 seconds to maintain a PH of 6.6. I do not understand how the PH can be 8.75 out of the tap but the water be so soft as to require such a small amount of Co2 to drop the PH (it took about 13 hours to drop from 8.75 to 6.6 and it stays there as long as I keep the Co2 at 1 bubble every 14 seconds).

Hopefully, I haven't rattled off useless information...

thanks!


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## Franco (Jun 25, 2010)

Hard and soft refers to the mineral content of the water, specifically calcium and magnesium. Hard water causes buildup of minerals in the pipes so municipal water companies remove some of the minerals to reduce the effect. That is what they mean by softening the water. They just replace some of the Ca with Na.
Chlorine has a high pH so when you take water straight from the tap and test pH it will be higher. Wait even an hour and it will go down because it is degassing its Cl.
You should do an experiment where you fill a container with water over night, another with water treated with detox conditioner, and then one straight out of the tap and do your tests on all of them.
I do that every time I move to get an idea of what I will have to do to have the water I want.


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## Grathum (Jul 13, 2010)

Ah yes, 

Thank you for your clues Franco! I am very used to my thinking in terms of my old water supply (chicago...super hard...lots of calcium because the water sits on limestone deposits). When you mentioned removing calcium it jogged my memory and I went and grabbed my copy of Ecology and low and behold the answer was right on page 86.

thank you much...


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## Franco (Jun 25, 2010)

I live in Iowa so it sounds like gravel is being dumped into the sink when you turn on the water.
It makes great water for African cichlids and livebearers but its a little high for anything else. All of the softwater fish I ever had only last a few weeks unless I knock down the pH and hardness.
I take a crappy old power filter and stuff the emptied cartridge full of garden peat, run the filter in a bucket of treated tapwater for a while and then test it to see what the parameters are. Then I yank the peat out and throw in some carbon to take the color out. If you presoak or boil the peat a little it will leach less color into the water. Bettas love those acids though.


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## Red_Rose (Mar 18, 2007)

Franco said:


> Bettas love those acids though.


Actually, bettas prefer a neutral pH. 

Another reason the pH could be higher is that some cities will raise the pH but not the hardness to prevent corrosion to the pipes that can happen with a more acidic pH.

I do find it interesting though that while your water is soft, the pH is higher yet here, our water comes from underground deposits that are loaded with limestone so our general hardness is high yet the pH is around 7.6. LOL


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## Grathum (Jul 13, 2010)

Yeah, I'm not liking the added sodium bicarbonate thing that mpls appears to be doing. I am now having to try and figure out what is actually going on with the test readings that I get. Yeah, my PH dropped from 8.75 to 6.6 in my tank with the added Co2...but what does that really mean when the calcium has been removed and bicarbonate added? I know that something is happening but I have never really been in a situation of sending 1 bubble per 14 seconds and having it mean anything...yet...the PH stays a stable 6.6. If I send a bubble every 12 seconds it drops down to 6.4 and the PH will rise if I send 1 bubble every 15 seconds (I haven't been able to fine it to send bubbles at less than 15 seconds). 

I can't find a freshwater Ca test...I have a GH test but if I understand what I have been reading it is basically useless in this siutation because you don't know what is causing the GH. I ordered some CaNO3 to dose in my test tank but it is going to be a pain since most of the plants I have in there are slow growers. I'm probably going to be dosing algae more than anything (interestingly since I set the tank up on July 1st I have not had any algae show up yet. I have been doing daily water changes however). I'm not sure why I didn't add a soil underlayer to the test tank but I was only thinking of finding out about the water at the time...sigh.


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## Grathum (Jul 13, 2010)

Red Rose,

From what I understand the city here is also softening the water and increasing the PH to deal with oncoming Zebra Mussels as well. Apparently a high PH but soft water inhibits their growth somehow (according to the city water report).

Looking at a map of the DS in the mississippi I guess there really aren't that many in the river starting out in minnesota but they increase as the river moves south. 

This has all been a great learning experience. I had no clue. I used to live in a neighboring city in minnesota that actually got it's water from underground wells (that sat on limestone deposits) so I never had to worry about dosing anything. The water was rock hard. I didn't have any issues growing the types of plants I grow.

This water from the river changes everything though. I feel like I need to go back to school and take a few chem classes. I was a business major so I just floated through the science stuff :0)


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## HeyPK (Jan 23, 2004)

I read somewhere that municipalities can soften their water with lime (calcium hydroxide). 
The calcium hydroxide reacts with the calcium bicarbonate to form calcium carbonate, which precipitates out. 
Ca(OH)2 + Ca(HCO3)2 → 2CaCO3↓ + 2H2O. This reaction can precipitate out a lot of the calcium bicarbonate, but there is a small amount of calcium hydroxide left dissolved in the water, leading to the high pH. The high pH is good because the pipes don't dissolve as much as they do if the water is acidic and you don't have problems with copper toxicity or corroded pipes. 

I don't see how this kind of water treatment could help with zebra mussels unless the mussels survive the chlorination and filtration treatments and grow in the pipes after the water has been treated. I thought the problem with the mussels was that they clogged up the intake pipes.


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## Grathum (Jul 13, 2010)

Well, I am not sure the mussles have made it to the MN stretch of the waterway yet. From the way it sounds they are preparing for their arrival. I think the mussles clog up the intake pipes and the internal workings of the processing plant. They state that they will use a permanganate if they make it into a processing plant. I assumed that those things can survive long enough to plant themselves at all points in the water delivery system. I have read that they are ridiculous survivors.

Now, the bicarbonates...you are saying calcium bicarbonate. I was assuming they were adding sodium bicarbonate. Am I wrong in thinking that if they were adding calcium bicarbonate that the water would be harder than 71? 

They don't mention specifically in the report what exactly they are doing to soften the water or increase the PH before delivery to customers...I assumed by re-reading the plant nutrient section in my copy of Ecology and the fact that the water is soft that it must be sodium bicarbonate they were adding. Of course I could be wrong...I am just trying to put everything together myself.


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## HeyPK (Jan 23, 2004)

Treating with lime, calcium hydroxide, is a recognized way of softening hard water that has a lot of calcium and magnesium bicarbonates. The treatment precipitates out most of the bicarbonates as calcium carbonate (maybe magnesium carbonate also), and leaves behind only a small amount of calcium hydroxide. The amount of calcium and magnesium is reduced considerably by this treatment. 

I have read that the zebra mussels don't survive the chlorination and filtration treatments, but that could be wrong.


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## Franco (Jun 25, 2010)

Baking soda is a sure fire way to safely raise your pH and hardness.


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## Franco (Jun 25, 2010)

Bettas DO love tannins and hummic acids. pH should be around neutral but the blackwater makes them bullet proof. Don't believe me? Buy 2 half dead bettas from walmart. Put one in blackwater and one in regular and I guarantee you that the blackwater fish will be completely healed within a week and blowing bubbles. Gotta do the right kind of blackwater though. Indian Almond Leaf (the real stuff) is amazing. Dried oak leaves make a decent immitation but those almond leaves release just the right amount of goodies and last a long time.


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## Red_Rose (Mar 18, 2007)

Franco said:


> Bettas DO love tannins and hummic acids. pH should be around neutral but the blackwater makes them bullet proof. Don't believe me? Buy 2 half dead bettas from walmart. Put one in blackwater and one in regular and I guarantee you that the blackwater fish will be completely healed within a week and blowing bubbles. Gotta do the right kind of blackwater though. Indian Almond Leaf (the real stuff) is amazing. Dried oak leaves make a decent immitation but those almond leaves release just the right amount of goodies and last a long time.


*No*, not all bettas like tannins and my Max is proof of that. I had added Blackwater extract to his home several months ago because I thought he would much prefer it only to find that he became far less active then when the water was clear. Once I removed the tannins with carbon, he perked right back up and went about his usual business. He much prefers his water clear then darkened.

Also, a tank can contain tannins without having an acidic or neutral pH as well as a betta can easily thrive in conditions that are nothing like the above. My first tank was like this. The water was a dark tea color yet my GH was near 30, my KH was anywhere from 17-22 and my pH was 8.2. My first betta did very well in this tank that when it was his time to go, it was from old age. My Max, however, has no tannins in his tank and the pH is at 8.0 and he's as happy as a pig in sh*t.

I've kept bettas for almost four years now and I learned a lot from people who have kept them for most of their lives so I don't appreciate you trying to insinuate that I don't know what I'm talking about when I KNOW my stuff.


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