RO water use, pH Buffer use, pH crashes, TDS, what the hey?

[Xerxes]

Lots of posts about pH recently, but didn't want to hijack someone's thread with a question of my own:

1) low KH could cause a pH crash,
2) RO (Reverse Osmosis) water is used to reduce KH so that pH is lowered easier,
3) pH buffers soften water or harden water doing what RO water does, but chemically
4) TDS (Total Dissolved Salts) affect fish health, apparently...

My tap water is 7.0 on the button and I have not been able to get it lower for a breeding tank (pH Down, drift wood, almond leaves use with KH at 3 dH and GH at 6 dH). My breeder/supplier kept my school at 6.0 to 6.5 he said too.

Then one day, my KH is going down to 2 degrees hardness, then 1 dH and my pH drops slowly to 6.0. My discus have a much better color to them and they seem happier.

So, what gives? Is low KH better (the reason I gather people use RO water, but cut it with tap or use Discus salts)? If so, how low. If KH low better, what factors in my tank make it more favorable as this much higher or that much lower in KH?

I gather that there is a KH sweet spot so that pH is lowered easily but does not crash? Btw, I am about to get a RO filter. What am I looking for or what make is best for us fish people?

I know, I ask a LOT of questions.

[ILLUSN]

KH IS A MEASURE OF THE AMMOUNT OF DISOLVED CARBONATE IN THE WATER.

some buffers use acids to split CO3 into CO2 (and H2O)
as kh drops so does pH, as CO3 is converted to CO2 (and H20 and carbonic acid) tds will drop, this drop in tds softens the water, wood absorbs CO3 and also softens the water s well as releasing tannins and humeric acids that lower ph.

alow kh leaves yo open to a ph crash, with ultra soft water (kh below 3 degrees) keep EVERYTHIG clean, any build up of organic matter will push equilibrium towards the production of nitric acid and a pH crash.

aim for 3-5 degress kH.

Ro kinda a waste of money, not just power but it takes 10-100L of tap water to make 1L of RO water.

[BobbyBruce]

Hi Xerxes,

I have been using RO water for a number of years and using Kent Marine RO Right to adjust to my requirements.

As Illusion has mentioned you will have waste water when producing RO water, mine goes onto the garden so is not a total waste. Modern RO units are now operating at approx 1:1 RO Water/Grey water. If you are looking for some good systems try here http://www.psifilters.com.au/ While based in Tasmania they provide very good service and Peter (?) has had a lot of experience with discus.

Good Luck,

Bob

[Xerxes]

KH IS A MEASURE OF THE AMMOUNT OF DISOLVED CARBONATE IN THE WATER.

some buffers use acids to split CO3 into CO2 (and H2O)
as kh drops so does pH, as CO3 is converted to CO2 (and H20 and carbonic acid) tds will drop, this drop in tds softens the water, wood absorbs CO3 and also softens the water s well as releasing tannins and humeric acids that lower ph.

alow kh leaves yo open to a ph crash, with ultra soft water (kh below 3 degrees) keep EVERYTHIG clean, any build up of organic matter will push equilibrium towards the production of nitric acid and a pH crash.

aim for 3-5 degress kH.

Ro kinda a waste of money, not just power but it takes 10-100L of tap water to make 1L of RO water.

So, ILLUSN, you use pH buffers? Which are good? Not necessarily brands, but the chemical composition is fine too. I'm kinda worried about byproducts being bad, but carbonic acid is soda water!! I'm guessing its not much produced? What concentrations are we talking about here (ppm or molarity or whatever quantitative measure is fine as long as it is quantative). A link to an existing post or web site is great too.

[Xerxes]

So, ILLUSN, you use pH buffers? Which are good? Not necessarily brands, but the chemical composition is fine too. I'm kinda worried about byproducts being bad, but carbonic acid is soda water!! I'm guessing its not much produced? What concentrations are we talking about here (ppm or molarity or whatever quantitative measure is fine as long as it is quantative). A link to an existing post or web site is great too.

Ok, I just saw in the other post, "Best pH buffer?" that the best recommended there is

Discus Buffer by Seachem.

[ILLUSN]

Depends on what you want the buffer to do. Discus buffer is good but don't use it in a planted tank. Acid buffer is good but more expensive and can be used in planted tanks. Both buffers use salts ( metallic cations) and will increase your tds. HCl will lower your ph and drop your kh. It's also cheap and has less of an effect on your tds

[Xerxes]

Depends on what you want the buffer to do. Discus buffer is good but don't use it in a planted tank. Acid buffer is good but more expensive and can be used in planted tanks. Both buffers use salts ( metallic cations) and will increase your tds. HCl will lower your ph and drop your kh. It's also cheap and has less of an effect on your tds

I read somewhere else here (I can't remember the post to cite it) that many institutional breeders use HCl and the poster said that hobbyists with huge tanks should do the same, but cautioned that it's dangerous and should be used with great care.

I get that, but why couldn't the average joe hobbyist just drop the HCl in an aging water reservoir tank, monitor until desired KH and tds and pH are reached (and so as not to shock the fish with too much of a difference in such numbers with the existing discus fish water chemistry) then proceed with the water change? No danger, best all around benefits.

That seems MUCH cheaper and even simpler than using RO water, and doesn't have the unwanted byproducts of buffers. People seem to age their water in a holding reservoir pretty much anyway. Since everybody isn't up and running out to do this (as far as I can tell), I figure that there's some catch? If so, please tell. I'm asking because I can't see the catch.

(I read somewhere else that people were having a hard time getting pure ammonia to do a fishless cycle, post 9-11 restrictions on available chemicals. Well, I was wondering just that I know of a plentiful supply of household ammonia. Actually, it's less household and more body-hold) (Before you turn your nose, literally, I actually cycled my breeder tank using this...source. If you're really grossed out by it like I was at first, you can do a major water change with the seeded biofilter, or sponge one, once the cycle is finished but before you add the fish).

[scoob]

HCL will drop the PH but to soften hard water you will need to filter with peat or RO machine.

[Hooked]

Hi Xerxes,
I don't really think there's a catch to people not using HCL. (maybe the thought of what the acid is capable of doing to cement, metals etc and the potential of harm to our beloved fish or ourselves if handled incorrectly) Just maybe its not really been common knowledge or had the benefits explained recently like not adding to the total dissolved solids etc. The info that comes out in the threads like this one you started is great for spreading the word and I for one will definitely be looking into it.
I looked up Hydrochloric acid on Wikipedia and this is a snippet of what the good people there had to say,

quote - pH Control and neutralization:
Hydrochloric acid can be used to regulate the acidity (pH) of solutions.
OH− + HCl → H2O + Cl−
In industry demanding purity (food, pharmaceutical, drinking water), high-quality hydrochloric acid is used to control the pH of process water streams. -unquote

Cheers

Hi ILLUSN,
have you found any particular source or brand that you would recommend over others? Also I know its a hard question to ask as all our water is different but "roughly" how many mls per 100lts or unit measure are you using to adjust your water. This will give me a rough idea of what to start with. I'm investing in a rain water type holding tank soon to age my water as a couple of plastic 44's are not keeping up any more so this is a great tip.

Cheers

Cheers

[Xerxes]

Kind words, Hooked.

Another question, however: What the hey, does TDS (Total Dissolved Solids) have anything to do with fishies keeping? Affects gas exchange in the gills for the fish? I read about a lot of stuff but not so much about TDS. (I did see that some vendors do sell a TDS meter).

Thanks in advance.