How fast can I drop the pH?

[PostalPenguin]

I have just started using pressurized CO2 on my 29g. My pH controller/powerhead diffuser has the ability to drop the pH by 0.2 every 15 minutes.thumbs2: So I theoretically could reach my target of 7.0 in an hour but that seems way too fast of a pH swing.

The pH is 7.8 without CO2 and is currently at 7.5. How fast can I adjust the pH down without stressing the fish? The pH controller will keep that pH constantly so I do not have to worry about pH swings once I reach my setpoint.

I decreased the pH on my tiger barb tank by 0.6(to 7.2) over the course of 72 hours and the fish never seemed to notice.

[William]

Your fish likely could handle that change in an hour. It can happen that fast in the wild. The shrimp however is a little more sensetive so I would allow it to take a little more time. How about lowering the pH 0.1 each hour. That will allow you to reach your goal in 5 hours and should be safe.

[rangur1]

to be on safe side i would drop ph .2 per day . what's the rush?

[PostalPenguin]

to be on safe side i would drop ph .2 per day . what's the rush?

Massive black brush algae outbreak. :scry: I have 72W of CF lighting and dose with excel but the stuff is slowly taking over so the CO2 is of absolute urgency, the stuff spreads every day. I have absolutely none of the stuff in my 20g with pressurized CO2 and I've read fluctuating CO2 levels can cause it.

I dropped the pH to 7.1 last night(~6 hrs) and all fish seem to be fine. I am going to hold it there until I get some drop checker liquid. As of this morning, before lights on, no fish were at the surface so I know the CO2 isn't too high.

[Wild Turkey]

The co2 isnt going to just cure your tank of BBA, its more of a preventative from what I have seen. Take your time getting the co2 where you want it, and kill off the existing bba with hydrogen peroxide spot treatments, that has worked well for me in the past. No need to risk it by speeding up the process, imo; as long as you start spot treating now, there should be quite a bit less or none by the time you have your co2 all set

[rich311k]

PH changre for CO2 will not effect you fish. It is PH changes from dissolved solids that cause the problems. My PH swings over a point everyday from CO2. The fish are more than fine.

I would remove as much BBA as possible, manually. Increased CO2 will help, to prevent further spreading or its return,

[Wild Turkey]

When you tear up live BBA you are spreading its spores all over the tank, wait til its dead to remove it IMO unless its already taken over the majority of the tank, it could make things worse.

[rich311k]

I have never heard that. I would remove all effected leaves, and take out and scrub all hardscape and filter parts. just nasty stuff.

[Wild Turkey]

"Removing it manually isn't the answer, because at the base of the hairs are spores, thus if you are careless in removing it, hundreds more colonies will appear. "

Dave66 Algae Primer

[rich311k]

I think I will keep snipping off the bad leaves works for me.

[Alfcea]

You know penguin? The problem with adjusting the pH is that, because of a mathematical property derived from chemical equilibria, at the beginning, the pH will appear to go down slowly and smoothly, but after you reach a certain point, it will "crash" and next thing you know, you'll have a pH of 4 or below. This is particularly true when the reagent that you are adding to the water is a gas -like CO2-. That is, in fact, one of the most common problems with carbon dioxide fertilization. You do have to keep a close watch on the pH...

If I were you, I would follow a mixture of Rich's and WT's advice. Cut off the really bad leaves. Do not try to clean the leaves in the tank to avoid spreading the spores, and treat the "not so bad" leaves with H2O2. I can tell you that I often use it and, though my BBA is not completely and totally off, it is not bad, and I can live with it happily....

[PostalPenguin]

You know penguin? The problem with adjusting the pH is that, because of a mathematical property derived from chemical equilibria, at the beginning, the pH will appear to go down slowly and smoothly, but after you reach a certain point, it will "crash" and next thing you know, you'll have a pH of 4 or below. This is particularly true when the reagent that you are adding to the water is a gas -like CO2-. That is, in fact, one of the most common problems with carbon dioxide fertilization. You do have to keep a close watch on the pH...


I have a very close 24/7 eye on the pH: a pH controller.thumbs2: If the pH ever started to crash the pH controller would simply shut off the CO2 into the tank and since the powerhead diffuser works under a slight vacuum, there is no residual pressure in the lines so the bubbles stop immediately.