my ph has been hovering around 6.4 or so, with diy co2

[mellowvision]

what would the reccomended course of action be to keep it around 6.8?

[mellowvision]

sorry, tank details: 20 gallon about 2/3 full, eheim canister filter, 75 degrees, 0 ammonia... running about 3 weeks now. fair amount of duckweed, giant hair grass, glosso, 2 anubis... 7 cherry barbs, 3 otos, 2 red claw crabs

[mellowvision]

I keep tap water treated with stress coat and florapride in gallon jugs, ready for use... just tested that for ph, and it was similar at around 6.4

[Mgamer20o0]

what is the tap water ph? i wouldnt mess with the ph it should be fine.

[mellowvision]

tapwater straight ph seems to be at around 7.0

[Mgamer20o0]

your fine dont worry about it. your prob at 15-20ppm co2. all good.

[Canuck]

I keep tap water treated with stress coat and florapride in gallon jugs, ready for use... just tested that for ph, and it was similar at around 6.4

Are you saying that your water directly from the tap is 7, and it is 6.4 after sitting but before CO2? If this is the case, then 6.4 is the natural pH of your tap water and your DIY CO2 is ineffective.

[J double R]

mine is virtually the same.. 7.2 out of the tap, 6.6 settled, and 6.4 with co2. youre just fine. :)

[Rex Grigg]

If the resting tap water pH is 6.4 then Canuck hit the nail on the head. Your DIY CO2 is not working.

And don't get hung up on trying to reach some "magic" pH. pH changed caused by CO2 mean nothing to the fish.

[Mgamer20o0]

Are you saying that your water directly from the tap is 7, and it is 6.4 after sitting but before CO2? If this is the case, then 6.4 is the natural pH of your tap water and your DIY CO2 is ineffective.

wow i so missed that part. good save canuck.

Rex Grigg is right. if the settled tap water ph is just 6.4 and your take is 6.4 there isnt any co2 getting dissolved into the tank.

try looking for leaks. also take the end of the tubing put it in some water to see if any co2 is coming out.

[mellowvision]

I have had a steady stream of co2 for weeks, bubbles galore, and have been diffusing first through an airstone, and then switched to a glass bubble diffuser... co2 bubbles are absolutely entering the tank. whether they are completely disolved or affecting ph may be up in the air.

but the question was, how to keep my ph closer to 6.8, where my livestock would prefer it.

[wesknox]

That's interesting your tap is 6.4. In my neighborhood I'd be checking calibration of pH meter.

[Canuck]

(If I'm reading your post right).

Long Answer
I wouldn't be concerned at the pH of your water at all (to make your fish happy). Assuming you are trying to recreate the "natural" water where your fish originate from, I think you should match gH and kH and ignore pH altogether. I'm not a fan of engineering your water but if that is what your doing, I don't think matching pH after CO2 injection is really what you want to do. Say the waters where your fish originate from are 4 degrees kH. Then the "natural" pH would be 7.6. This is a simplified example most waters contain humic acids and tannins which depress pH. I suppose you could use CO2 to do this, but (big but) I'm not confident this would be of any benefit to your fish. My advice use CO2 to grow plants. And I understand its your tank to do with as you please but unless your trying to breed fish or something, I'd just acclimated them to the water you have, they'll do fine.

Short answer:
Baking soda will raise both pH and kH. Add very slowly (over a number of days), and make sure water used for water changes is matched to tank parameters.

PS. I don't know whether this helped you but it confused the h*ll out of me.

[mellowvision]

just to clarify, I am not trying to change the ph with co2, the co2 is for the plants. I was simply concerned that it was getting lower than I wanted it.

[phanmc]

Don't worry about the pH level, a change of .4 is negligible and the drop from Co2 isn't important. You can do more harm tampering with the pH than having it lower than desired. Fish are adaptable, what they prefer isn't exact or all that important. I've seen african cichlids live for years and spawn in soft water when everyone says they prefer hard water.

[Mgamer20o0]

the lowered ph from the co2 will not effect the fish.

[mellowvision]

I did a water change today, 4 gallons, and tested the ph about an hour later... came up with a 7.0.

this was done using the gallons of water I had previously treated and tested at 6.4... to a tank that was reading close to 6 before the change.

I've had co2 off and on over the last week, been trying different set ups, so it hasn't been consistant.

odd, if you ask me. not what I expected.

[cichlidkeeper91]

Yea but usually the water Ph level drops with co2.

[mellowvision]

the water I added to the tank had no co2, it was water that was treated with stress coat and florapride, and left to sit for a week.

[Canuck]

What is the kH of your water?