best treatment of RO/DI water for FW community?

[hbeth82]

Recently bought an RO/DI unit because the nitrate in the tap water is above 40ppm (bad for fish) and the GH is 190+ (bad for turtle). Thankfully, the filter seems to be taking all the bad stuff out. However, making the RO/DI water fish and turtle friendly is proving to be a pain in the :butt:! I'm raising the GH with Seachem R/O Right and that seems to be okay, but not sure what to do about the KH. Some sites suggest baking soda saying that calcium carbonate does no good, and other suggest using calcium carbonate because baking soda can quickly screw up the water.

So, what are other people using and in what amounts?

BTW, a very wise forum member had already cautioned me about all of this and I though I had no doubts about that member being right, didn't know what else to do. Still, it kinda stinks when the things you know will happen actually happen

Thanks!

 

[mfdrookie516]

Well, hopefully that 'very wise forum member' will chime in and help out, but I would suggest crushed coral. It'll keep the ph right at about 7.8. Since you're using Ro/di, you could just put some cc in your reservoir and then also have some in the tank. that way both the water you're adding and the tank will have the same ph and wont have to worry with it. That's how i would do it at least... where's jsoong when ya need him

 

[WhiteDevil]

mix your ro/di with tap. dont need alot but a few tests worth, see where you are at. I was at 8.8 out of the tap, with my RO/DI it was 6.9 with O/O gh kh, added 1/4 cup tap to 3/4 cup ro/di and went from there on the GH and KH to get it where it was needed.

I was 17 kh I am at 5kh now just mixing in tap to the mix.

 

[hbeth82]

Well, hopefully that 'very wise forum member' will chime in and help out, but I would suggest crushed coral.

Yep, there he is again! Not sure I want the pH quite at 7.8 but would be better than the 6 that it is now. Will it replace the Seachem RO Right by adding to the GH or just up the pH and KH? Are some brands of crushed coral better than others, or is it pretty much the same stuff? Saw that the stuff sold by Foster & Smith boasts that it contains aragonite (again, high school chemistry was hardly my strength). Is there any way to know how much to add or is it just trial and error?

mix your ro/di with tap. dont need alot but a few tests worth, see where you are at. I was at 8.8 out of the tap, with my RO/DI it was 6.9 with O/O gh kh, added 1/4 cup tap to 3/4 cup ro/di and went from there on the GH and KH to get it where it was needed.
I was 17 kh I am at 5kh now just mixing in tap to the mix.

I'd thought about doing it this way but trying to eliminate as much nitrate as possible. May still do it for the turtle tank, since it's the GH and not the nitrate that are a problem for her.

Thanks!

 

[WhiteDevil]

that will bring the Gh down. or up, it brought mine down.

 

[hbeth82]

that will bring the Gh down. or up, it brought mine down.

Do you mean adding the crushed coral or adding the tap water?

 

[WhiteDevil]

thats with TAP, sorry for not making it clearer.

if you want the BEST RO help, Look at discus specific forums, those guys have this stuff down to an art.

I dont use CC as I need very soft water. and I believe CC raises things like Gh and Ph, though not sure, like I said I dont use it.

 

[hbeth82]

Thanks, that helps. I'm really not sure what would work best because I would like to keep the nitrates at 0, the pH just a hair above neutral, and then 'soft' for GH & KH. So the CC would work but I don't want to raise the pH quite as much as mfrdookie indicated it could. Will try to check out a discus forum but still open to ideas!

 

[hbeth82]

This may seem kinda dumb but are Nature's Ocean Coral substrate & Tideline Natural Coral Sand actually crushed coral? From the name, seems like they should be but can't find the words "crushed coral" anywhere on the bags.

 

[jsoong]

Most white sand beaches' sand actually comes from broken down coral & shells, so they basically are CaCO3, and will act like crushed coral. <Other sources of CaCO3 would be crushed oyster & other shells, even eggshells.>

Anyways, cc is prob not what you want if you want the pH to stay around neutral. CaCO3 will raise pH to ~7.8, which is its equilibrium point, and the water will be mod hard (~2-300 ppm). You might be able to control the pH a bit better with baking soda, but you will not get a half decent buffering capacity without the pH in the 7.4 range.

In order to have neutral water that is well buffered, you will have to use a non-carbonate buffering system. Kent's R/O right & Seachem's neutral regulator are some of the products on the market. Essentially, you are adding back some of the Ca & Mg (GH) and a buffer for a specific pH. <That is usu. a phosphate buffer, so will not show up in the KH test ... but the buffering action is there & the pH should remain stable.> I have not used any of the products, so I can't tell you which one is better. As others had said, the discus keeper would have the most experience in doctoring R/O water to neutral or low pH.