What rate is safe when raising PH

[the other tang]

I finally got my low o2 in my house issue to a manageable level but still have low ph from time to time. Thank God its 70 out I can just open a window. My question is when it does dip at what rate can I safely raise it? One point per hour, per day...etc. I check it several times a day. but sometimes when I get home from work its as low as 7.9, i really try to keep it at 8.2. Can I just dose kalk till it hits 8.2? I'd say no after looking at my shrooms reaction, they start shrinking and some hurl their insides into the water column. Then My skimmer goes nuts.

 

[bertoni]

The rate of change isn't very important, as long as the pH doesn't get outside the acceptable range. You can dose kalk, but that will change salinity, too, which can be a problem. I'm not sure why your mushroom corals reacted, though, unless they got an extra-concentrated blast, or SG became a problem.

 

[zeusfc]

ok, so in a tank, the ph dips after lights out... so should that 8.2 be the days' average figure, the highest point, or the lowest point it reaches?

also can someone tell me... as all the algae in the sea photosynthesize too... does the ph at any given location... (say a rocky bay, or a reef) also dip at night... and if not, why not?

 

[bertoni]

For the open ocean, the pH is fairly constant. The same is true of reefs with lots of flow from the ocean. For lagoons and bays, the pH can drop the way our tanks drop.

I would try to keep the daily low above 8.0 or 8.1 or so, and the daily high under 8.6. I wouldn't worry too much as long as pH stayed in that range.

 

[the other tang]

Bertoni, thanks for the info. I don't blast them, I even dose in front of my power head flow to diffuse the kalk. Then I even dose it slowly over time. I use buffer the same way when needed and get a similar reaction. The shrooms come back as good as ever after several hours. My inverts run for cover at the same time, anemone retracts in his rock. I do watch the sg. I dose kalk two ways. First in make up water, and in concentrate direct but slow as stated above. The concentrate dose should not cause a dif in sg, right? We are talking about ounces in a 40g tank.

 

[bertoni]

I wouldn't dose limewater except as top-off, personally. That can introduce impurities into the water, and lime is fairly caustic. I'd consider aeration as the next step.