The Planted Tank Forum - View Single Post - New to CO2, pH went from 7.4 to 6.6, can I raise it?
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post #1 of (permalink) Old 09-15-2020, 05:40 AM Thread Starter
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New to CO2, pH went from 7.4 to 6.6, can I raise it?

First timer doing CO2. I have a CO2Art setup ("SE" regulator + bazooka diffuser + drop checker) on a new ~70% planted 50 gallon. No critters yet, just plants (plants in approx order of area: dwarf hairgrass, rotalas, dwarf baby tears, swords, anubias).

I ran the CO2 for first time today. I knew pH would go down. I started at 7.4. At drop checker = green, I was at 6.6 (and I believe from the charts I was at ~30ppm CO2). I will be housing my many Endlers and adding both red cherry and amano shrimp. I know plants like a lower pH into the 6's but my Endlers I believe prefer 7-7.5 and have been living in that pH range. I'm thinking I would like to target 6.9 to get a happy middle ground. I have Seachem Alkaline Buffer on order.

My relevant tap water parameters are:
- 50-100ppm KH (based on API master kit), paper test shows ~80ppm
- 200-300ppm GH (based on prior readings with a Hanna probe and a truncheon, have an API test kit on the way)
- ~7.4pH (based on API master kit and paper test)

I also have a lot of Seiryu stone, which fizzled quite a bit when I prepped it in vinegar but it does not appear to affect my KH, at least as of yet. I wouldn't mind if it did and thought it might...

Anyway, based on a drop checker chart, it looks like to accomplish a move from 6.6 to 6.9 @ 30ppm CO2, I need to raise KH from 4 degrees of KH to 8 degrees of KH (or to about 144ppm). I'm sure the Seachem product will have a formula to calculate how much product to use.

I have a few questions:
1. Is it this straightforward to increase pH when using CO2 to just add some bufffer?
2. Does it raise my nominal pH also? So if CO2 is not on and I add fresh tap water prepped with the buffer, instead of 7.4 pH, should I get 7.8?
3. When I turn my CO2 off in the evening, does pH then go back up as CO2 is released and no more added to replace it (have not checked yet)? Doesn't this make using CO2 a pH yoyo? Does the buffer reduce the "swing" size any or does it just change the hi and low values of the pH swing by the same amount?
4. Will 8 degrees a KH (~144ppm) cause any issues I need to watch out for?

Appreciate any help!

Last edited by ahem; 09-15-2020 at 05:41 AM. Reason: added word "pH", confusing without it
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