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partial ro water changes?

718 Views 6 Replies 3 Participants Last post by  Sucram Nosiren
alright .. so my city water sucks .. nitrates read 40 right out of the tap ph of 8.2 (which my guppies dont mind) tds is up there as well
im tryint to figure out how to get my nitrates down .. what could i add to the ro water to raise the ph or remineralize .. my plan is to get a huge rubbermade trashcan to mix and store the water .. with aeration and heat but i need some advice on doing this safely without altering the ph and keeping everything else stable .. please help .. doesnt seem like anyone can help me with this problem ive got too much wrapped up into my tanks to give in to crappy water quality ... and doing all ro water isnt an option as i have a 30 a 36 and a 40 gallon and just a honda accord to haul the water with
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I'm guessing you don't live in the US? The EPA sets a limit of 10ppm due to health concerns (mostly long term exposure for youth).

To raise pH (and KH will always go up with it), you can use sodium bicarbonate which is also known as baking soda. This is both measurable and stable.

I'm curious why you would want to maintain an 8.2 pH though. Periodic water changes with the mixed RO will bring that down so gradually that nothing would be hurt by it if you wanted to lower it. Also, if you really want to keep GH / TDS the same, you need to add GH booster.

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I'm guessing you don't live in the US? The EPA sets a limit of 10ppm due to health concerns (mostly long term exposure for youth).

To raise pH (and KH will always go up with it), you can use sodium bicarbonate which is also known as baking soda. This is both measurable and stable.

I'm curious why you would want to maintain an 8.2 pH though. Periodic water changes with the mixed RO will bring that down so gradually that nothing would be hurt by it if you wanted to lower it. Also, if you really want to keep GH / TDS the same, you need to add GH booster.

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i wouldnt mind the ph eventually settling down around 7.6 my kh/gh is high like 200 to 400 from the tap , i live in the us but ive used 3 test kits 1 seachem 2 api and all read high out of the tap .. the water company came and took some water to test with a laser something or other and called me back telling me its only 5 ppm .. thats when i bought the second api kit and the seachem kit .. all read the same , well over the allowed 10 ppm ..

now with my having such a high kh/gh would that make the ro water affect my tank ph less ... what kinda ratio should i be looking for ? i do run co2 and i read that co2 can affect fish more with softer water .. lol i dont know what to do .. but i need to do something
I use reconstituted RO water for my tanks because my tap KH is anywhere from 8 to 10 dKH (about 115 to 150 ppm). I use Seachem Equilibrium for my GH (I shoot for a GH of 5 dGH or 89 ppm) and sodium bicarbonate to set my KH (I shoot for 1.5 dKH or 22 ppm). Your guppies might like a KH more like 6 (about 90 ppm). GH in typically doesn't affect fish, only plants. I would not get hung up on actual pH, worry more about getting the proper KH. If the only thing buffering your water is carbonate, your pH will be around 7.8.

Edit: I looked back at your post and saw you measured your KH/GH in ppm, I used dGH which is about 18 ppm and dKH which is about 15 ppm.
where how do you get dkh and dgh readings?

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i wouldnt mind the ph eventually settling down around 7.6 my kh/gh is high like 200 to 400 from the tap , i live in the us but ive used 3 test kits 1 seachem 2 api and all read high out of the tap .. the water company came and took some water to test with a laser something or other and called me back telling me its only 5 ppm .. thats when i bought the second api kit and the seachem kit .. all read the same , well over the allowed 10 ppm ..

now with my having such a high kh/gh would that make the ro water affect my tank ph less ... what kinda ratio should i be looking for ? i do run co2 and i read that co2 can affect fish more with softer water .. lol i dont know what to do .. but i need to do something
Where did they treat the water from and are you treating from the exact same spot? Old homes with coated pipes or things like that could affect it in the home but the street would test fine.

GH does not affect pH, and KH buffers how acids affect your pH. As far as I know, KH won't affect the change caused by mixing RO water. It should be quantity based.

As for CO2, KH buffers the carbonic acids which slows the change of pH due to CO2 injection. GH, which is usually what people refer to as soft or hard water, does not affect CO2 injection. Higher KH requires more CO2 to make a difference, so you'll use up more CO2 at a KH of 8 than you would at 4. I personally am somewhere between 3-4 dKH and find it buffers pH swings well while still not requiring too much CO2.

Personally, I'd figure out the source of the nitrates if at all possible first, then look at mixing RO as you can. If you make the mix consistent, you'll stay stable and can really decide what parameters you want to target since you can now measure it.
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Where did they treat the water from and are you treating from the exact same spot? Old homes with coated pipes or things like that could affect it in the home but the street would test fine.

GH does not affect pH, and KH buffers how acids affect your pH. As far as I know, KH won't affect the change caused by mixing RO water. It should be quantity based.

As for CO2, KH buffers the carbonic acids which slows the change of pH due to CO2 injection. GH, which is usually what people refer to as soft or hard water, does not affect CO2 injection. Higher KH requires more CO2 to make a difference, so you'll use up more CO2 at a KH of 8 than you would at 4. I personally am somewhere between 3-4 dKH and find it buffers pH swings well while still not requiring too much CO2.

Personally, I'd figure out the source of the nitrates if at all possible first, then look at mixing RO as you can. If you make the mix consistent, you'll stay stable and can really decide what parameters you want to target since you can now measure it.
they tested from the same tap i test from , are there different forms of nitrate like nitrogen etc that they would have tested for separately?

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update .. well i now have seachem equilibrium alkaline buffer and acid buffer on the way ... along with a r for my 50 gallon trash can .. which happens to be the perfect size to do 50 percent water changes on all my tanks ... picking up a submersible pump tonight ... hope i do this right lol
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