Kalk and High PH options ?

cjrudy · Jan 27, 2016

I have been using Kalk in my top-off to maintain CA and Alk in my SPS dominant 17 gallon tank. The trouble is I've had to reduce the amount of kalk per gallon because of high PH, down to 1/2 tsp per gallon and my PH still hits 8.6 during the day. With the reduced kalk I can no longer maintain CA and Alk.

What should I do, ditch the kalk and start two-part or try to reduce the PH in my kalk with vinegar ?

Or maybe another solution ?

CodyRVA · Jan 27, 2016

I would knock the kalk back until your PH is in a good place, and supplement the loss of CA and ALK with two part solutions

Randy Holmes-Farley · Jan 27, 2016

There certainly are other solutions, but I suspect testing error first at that dose.

When was the last time you calibrated the pH meter?

If real, more aeration will bring the pH down, as long as the alkalinity is not super high.

cjrudy · Jan 27, 2016

Randy Holmes-Farley said:
There certainly are other solutions, but I suspect testing error first at that dose.

When was the last time you calibrated the pH meter?

If real, more aeration will bring the pH down, as long as the alkalinity is not super high.

Thanks Randy, I have re-calibrated the probe a few times and also used a test kit and it consistently reads 8.5 by the evening. Before I started cutting back the kalk it was pushing 8.6-8.7 I think I have pretty good aeration, between the AC50 filter, mp10 and Tunze 9004 protein skimmer which surface skims.

Alkalinity runs 7.8 after a water change and will drop down to 7.2 after a week and 6.7 after two weeks at the current 1/2 tsp of kalk. Its a very slow drop but I would like to keep it consistent.

Randy Holmes-Farley · Jan 27, 2016

People think they have very good aeration, and you might, but if you do, the pH is wrong. CO2 is hard to equilibrate:

https://www.reef2reef.com/threads/h...ium-to-establish-in-a-normal-aquarium.232312/

Total aeration of your tank water would give a pH of 8.2 at the most (and less if your home has elevated CO2 in it). It also would not change day to night the way most tanks do.

In fact, this is a good check on the pH measurement. Take out a cup of tank water at pH 8.6 and aerate it for an hour with an airstone. It should drop a lot. If not, the measurement might be in error, perhaps because the calibration buffers are old and CO2 has entered the pH 10 buffer, lowering it and making your pH read incorrectly high.

That said, my tank using limewater ran between 8.35 and 8.55 for years due to limewater use, and I don't think that is an issue. (Then I got new storm windows and the pH range dropped a bit).

This has more:

High pH: Causes and Cures by Randy Holmes-Farley - Reefkeeping.com
http://reefkeeping.com/issues/2005-03/rhf/index.htm

cjrudy · Jan 27, 2016

Thanks Randy, I will work on figuring out my PH exactly before ditching the kalk and trying anything different.

Funny thing is, for years living in New York state I struggled with low PH, now I've lived in Florida for six months and I am struggling with high PH

Randy Holmes-Farley · Jan 27, 2016

Maybe you have fresher air now.

cjrudy · Jan 27, 2016

That's'also where I am confusing myself, up north I was constantly trying to introduce fresh air to reduce CO2. I was always complaining that my wife lit too many candles in the house, I even ran an airline from outside to my skimmer.

Now I need more CO2.................Maybe I'll tell her to burn more candles....LOL

Randy Holmes-Farley · Jan 27, 2016

Dare I suggest it but... heavy breathing might also solve the problem.

cjrudy · Jan 28, 2016

Well Randy, you were right of course

For as many times as I had re-calibrated my probe or tested with an API kit, the reading was wrong. I tossed the buffer I was using and opened up two brand new buffer packs. Bingo, my PH reading was at least .3 lower. So I have upped the kalk a 1/2 tsp, back to 1tsp per/gallon. I will monitor PH and see if that can hold my alk

How long do those Milwaukee buffer packs last once open ?

Randy Holmes-Farley · Jan 28, 2016

cjrudy said:
Well Randy, you were right of course

For as many times as I had re-calibrated my probe or tested with an API kit, the reading was wrong. I tossed the buffer I was using and opened up two brand new buffer packs. Bingo, my PH reading was at least .3 lower. So I have upped the kalk a 1/2 tsp, back to 1tsp per/gallon. I will monitor PH and see if that can hold my alk

How long do those Milwaukee buffer packs last once open ?

That's good to hear!

Once open, pH 10 buffers begin to drop in pH due to CO2 entering. pH 7 buffers can too, but not as fast. How fast they drop depends on how open they are to the air, but generally I would not reuse a small packet for more than a few hours, and even then try to keep it closed.

A larger bottle lasts much longer, and if you have a meter that can take buffers of any pH (say, 6.93 and 9.81), then you can keep using the bottle forever, just once in a while rechecking it against a new packet and getting a new reading for it (I do this).

cjrudy · Jan 28, 2016

Oh wow, learn something new everyday. For years I have opened those packs from Milwaukee, calibrated and kept them for months at a time. Never knew the solution would change.

Maybe I'll use the bottles instead .