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Discussion Starter · #1 ·
Hi, I would to hear people's experience with ultra soft water with almost no KH and PH well below 6 degrees. Has your result been tremendous compared to before? Is it correct that below PH 5.5, biological filter will not work. Has this been an issue for you guys? Please share your experience.
 

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I've never heard of the biological filter not working below a pH of 5.5. But with zero kH and an already low pH, that's just screaming for a pH crash. With nothing buffering the water against it, it's bound to happen at some point. I'd definitely get some kind of hardness booster that adds kH into the water, or add some kind of calcerous substance to the filter or gravel (like limestone, oyster shells, aragonite, etc.).
 

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I wouldn't see this as a good thing. I'd fix it as soon as possible, but slowly. A partial water change ought to get you out of immediate danger, the amount depending on how hard your tap water is.

The next day, consider targeting some kH number like 3, for example, by adding baking soda.
 

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John, you have nothing to worry about with the water we get in N.Y.. Granted we do have very soft water but it's nothing to be alarmed about. If you like, you can add a GH Booster located here, here and here.

My pH is 5.5 and all is well. I add GH Booster when I remember to but there are times I forget and guess what, all is well. Again, nothing to worry about. There are quite a few of us New Yorkers here with the same water who have grown very beautiful plants and the fish doesn't seem to mind the low pH either.

Obviously there are certain fish you can't keep in soft water however there isn't one plant that I've kept that hasn't grown for me. Just a thought.

Also don't put too much stock in the hobby test kits we purchase. Most of the readings we get are within a range of what the actual reading is. Its not accurate at all unless you go professional on the test kit which is very expensive.

Dan
 

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I've never heard of the biological filter not working below a pH of 5.5. But with zero kH and an already low pH, that's just screaming for a pH crash. With nothing buffering the water against it, it's bound to happen at some point. I'd definitely get some kind of hardness booster that adds kH into the water, or add some kind of calcerous substance to the filter or gravel (like limestone, oyster shells, aragonite, etc.).
what kind of info do you have to back this up? :icon_roll

people have been running tanks with zero KH for many years without 'crash'. Many natural environments are lacking carbonate and have very low pH with no ill effect. Is it a specific livestock concern, because the general case of low KH causing problems is a myth perpetuated in internet forums and petshops.
 

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what kind of info do you have to back this up? :icon_roll

people have been running tanks with zero KH for many years without 'crash'. Many natural environments are lacking carbonate and have very low pH with no ill effect. Is it a specific livestock concern, because the general case of low KH causing problems is a myth perpetuated in internet forums and petshops.
Nice eye-rollie. You asked for free advice, and you got what you paid for. You ought to either discuss it like an adult, or just say thanks and move on. Just my $0.02.
 

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Nice eye-rollie. You asked for free advice, and you got what you paid for. You ought to either discuss it like an adult, or just say thanks and move on. Just my $0.02.
not sure I understand. I'm not the one asking for advice here, just trying to confront an ancient myth. Get up on the wrong side of the bed today?
 

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Discussion Starter · #9 ·
Guys - relax! Let's keep it civil. I asked a simple question and that is to find out people's experience with zero KH and low PH water parameter. I'm thinking of going this route and before doing so, I would like to hear if people who tried it have postive or negative experience, so that I can learn from others.
 

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I've never heard of the biological filter not working below a pH of 5.5. But with zero kH and an already low pH, that's just screaming for a pH crash. With nothing buffering the water against it, it's bound to happen at some point. I'd definitely get some kind of hardness booster that adds kH into the water, or add some kind of calcerous substance to the filter or gravel (like limestone, oyster shells, aragonite, etc.).
I'm almost positive that CO2 cannot drop the pH below about 5.5, because of the chemistry involved. CO2 in water results in a mix of carbonic acid, carbonates and dissolved CO2. At the temperatures we keep our tanks at, the amount of carbonic acid doesn't increase as the amount of CO2 being added increases once the pH is around 5.5. If I were less lazy I would look up the reference for this, but I'm pretty sure it was given in The Barr Report.

Like a lot of information circulating in this hobby, I think the "pH crash" is just a myth.
 

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We have very soft water and I've had no issues that I'm aware of. I add a tbsp of Equilibrium at each water change to make sure there's enough magnesium and calcium for the plants. When I first started a planted tank I was adding 3 times that amount of equilibrium and also adding sodium bicarb to bring up the KH. After doing a bit more reading I concluded that there was no need to alter the KH and I only needed enough GH to provide enough Mg and Ca. I've not noticed any difference in plant or fish health. Just because I like posting pics, here's one of my low KH/GH tank. :)

 

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I disagree that pH crash is a myth. It can happen, though not "in a vacuum" and is usually part of an entire chain of events in a tank crash. One of the big issues with pH fluctuations is not only do N-bacteria stop functioning below approx 6.0 pH (well documented, do a quick google search), but toxicity levels of ammonia and nitrites are altered based on pH levels.

These tend to be worse issues in non-planted tanks than planted, as the plants themselves serve as pretty effective buffers against both pH swings and ammonia & nitrite issues.

All that being said- to the OP; if your tank is well planted, plants are doing fine, and you're maintaining a regular water change regimen, I'd leave well enough alone and not worry too much about your water hardness and pH.
 

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but toxicity levels of ammonia and nitrites are altered based on pH levels
altered, as in ammonia becomes something much less toxic. Dirty, overstocked tanks are a better target of fearmongering. pH crash as it is typically presented (low carbonate = eventual disaster), is a myth. Otherwise natural sources for several of the tropical fish we keep would 'crash'. The upper Rio Negro comes to mind as a good example, with water pH as low as 4.5 and hardness of zero.
 

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Discussion Starter · #15 ·
Hoppy,you are correct. If we are talking about distilled water, the lowest that PH can drop is 5.7, regardless of how much co2 you inject. However, people who use ADA aquasoil, PH can go much lower.

I remember Tom Barr said that in general the harder your water is, the more macro you need. The softer the water, the lower the macro. That makes a lot of sense to me. My guess is that plant have an easier time absorbing nutrients when water is soft. Also if you look at amazonia biotype, KH is almost nonexistent and nitrate are below 1PPM, yet plant grows lush and green. Granted most of the nutrients come from the soil.
 

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altered, as in ammonia becomes something much less toxic. Dirty, overstocked tanks are a better target of fearmongering. pH crash as it is typically presented (low carbonate = eventual disaster), is a myth. Otherwise natural sources for several of the tropical fish we keep would 'crash'. The upper Rio Negro comes to mind as a good example, with water pH as low as 4.5 and hardness of zero.
Nitrites are more toxic when ammonia is not, so it's a catch-22.

And a natural riverine system isn't a compatible analogy to a closed artificial environment.

Rapid pH swings can impact any biological system. (Friend of mine held cancer at bay for a few years by changing the pH of his internal chemistry through diet- quite an amazing feat, actually!) In a non-buffered tank, water changes can produce very rapid pH changes, which can cause problems. Eggs and fry are especially susceptible to such changes, which is part of why many breeders don't do water changes for at least a few days after eggs hatch.

There's a big difference between understanding the principles at work versus "fearmongering."
 

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Good point. The words pH crash do sound disastrous but I think they only refer to the rate at which pH can drop. IIRC the alkalinity required from pH point to pH point is exponential so when it gets low, the pH drops out quickly.

That said, My fish don't seem too bothered when it happens.
 

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There's a big difference between understanding the principles at work versus "fearmongering."
I dont log on here much anymore, but I do remember you LL.
Remember biogenic decalcification? still worrying about the slim margins of possibility? I gave up trying to convince people 0KH isnt scary. Seems like theres always an open thread someplace on it. :D
 

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LOL

Yep, that was a fun thread! :D

I'm of the opinion that people tend to go to one extreme or the other- either blithely disregard pH and pretend it has no relation at all to anything that happens in their tank, or that it's the be-all-and-end-all most important factor in maintaining water quality. Like most things in life, the truth is somewhere in between and a bit more complex.

Good point. The words pH crash do sound disastrous but I think they only refer to the rate at which pH can drop. IIRC the alkalinity required from pH point to pH point is exponential so when it gets low, the pH drops out quickly.

That said, My fish don't seem too bothered when it happens.
If your pH change is being caused by CO2 injection, those pH fluctuations don't seem to impact fish at all. TDS-related pH changes have more impact on livestock than gas exchange.
 

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I do watch TDS but dont talk about it much. Seems its not a very popular parm in planted aquaria and I get 'well, you dont know what makes that number up..' and so forth, which is true in a way.

but I ignore pH, dont test it etc.
Wrong or not, I've decided it isn't important and its worked out pretty well so far. I wont preach on it though. Whatever works, I suppose. I'm more into the gardening aspect of the hobby. Less into the science and wondering what's going on.

cheers LL
and crikey! your post count. gulk!
do you have like a voice dictation thing or something?
I think my fingers would be worn out :D
 
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