Kalkwasser and pH

[dss190]

What is an acceptable limit to raise your pH at any given time when dosing Kalkwasser? I've been told not to raise it more than .02 at a time. Any opinions or advice is greatly appreciated.

 

[DFW]

Here is a dosing calcualtor. When you calculate dosing saturated lime water for alkalinity, it will have a few words to say at the bottom of the page about this.

'Reef Chemistry Calculator FV'

 

[Randy Holmes-Farley Verified Community Expert]

IMO, 0.02 pH units is ridiculous.

I'd personally be more concerned with the high and the low that is attained each day than the changes during a day. I don't think that organisms respond much to rapid pH changes within the normal range we see (say, pH 7.8 to 8.5). It is not like their interiors are changing in response to it. The pH inside of organisms is very tightly controlled.

That said, spreading out the daily addition of limewater over many hours is optimal so that the ph doesn't rise too high (or too much, if that does concern you).

Adding 1.25% of the tank volume in saturated limewater all at once will boost pH by about 0.6-0.7 pH units, which is generally too much.

That is why people either drop it or use very slow pumps (such as a slow ATO). I use the latter, and have done so for 19 years.

This has more on limewater:

What Your Grandmother Never Told You About Lime by Randy Holmes-Farley - Reefkeeping.com

and

The Many Methods for Supplementing Calcium and Alkalinity - REEFEDITION

 

[dss190]

Thanks Randy. That's why I came here, I knew I would get good advice. I just wanted to know what would be to much at one time. I only need 2 tps per 5 gallons now in my ATO now, but wanted to know when the time comes when I'll need to add more.

Thank again.

 

[Randy Holmes-Farley Verified Community Expert]

At that dose you can add quite a lot at once. Probably at least 0.5% of the tank volume at once is OK.