Low pH - High Alk

[Cathy8424]

How do I raise my pH without raising my Alk? How do I lower my alk?

My pH has started running 7.7 to 8.04. My alk is 14.4. My calcium is 300

I drip about 2 gallons of Kalk per day in a 125 gallon tank.

I have added more kalk, upped the calcium additive and nothing works.

Until this past week, my pH had been steady at 8.15 / 8.3. I had done nothing different.

Thanks, Cathy

[Randy Holmes-Farley]

First, I'd suggest raising the calcium to 420 ppm with a calcium only supplement like calcium chloride.

Then, while adding the limewater (kalkwasser) in an ongoing way, I'd continue to add more calcium chloride to shift the balance to more calcium and less alkalinity.

Finally, to raise the pH more you'll either have to use more limewtaer, or to aerate the water more with fresh air.

The chang ein pH might be a testing error. How was it measured?

It might also be that you closed up the house to air condition, and CO2 is now elevated in your home.

These articles should help:

Solving Calcium and Alkalinity Problems
http://www.advancedaquarist.com/issues/nov2002/chem.htm

Solutions to pH Problems
http://www.advancedaquarist.com/issues/june2002/chem.htm

[Cathy8424]

I have been adding a calcium (kent) only supplement and will continue to do so. I am about out and will start using the calcium part of B-Ionic.

We do have 5 more family members now. I guess that could cause a Co2 problem.

Since then, I have vented my skimmer with outside air.

I have been adding alot more Kalk. Can I add to much, or am I safe as long as the pH and calcium isn't to high?

I have two meters that have been calibrated and a Salifert test kit.

[Randy Holmes-Farley]

You need to add a lot more. It takes a lot. Forget the manufacturers directions. This calcualtor can help you know how much B-ionic to use:

Reef Chemicals Calculator
http://www.kademani.com/reefchem.htm

You need on the order of 900-1000 mL of B-ionic (calcium part only) to raise calcium from 300 to 420 ppm in a 125 gallon tank.

As long as the pH and alkalinity are not too high, there is no real concern with dosing too much limewater.

[Cathy8424]

Thanks a million!!! That is an awesome calculator. I have not been adding nearly enough calcium (2 t per day).

[Randy Holmes-Farley]

You're welcome.

Good luck. :)

[TacoKing]

Randy,

I've been experiencing low PH problems the past couple weeks also. Until a few weeks ago PH was in the 8.1 - 8.3 range, but one day it dramatically dropped down to 7.5. Last night i ran my skimmer input outside to try to pull in some fresh air. Well, I woke up this morning with PH at 7.48. Quite low if you ask me.

I'm currently not dosing Kalk or any other additives, just running my Ca reactor real low. My ALK is in the 10.5 range and Ca 380.
Any idea what could be causing this low PH? I was hoping it was just a CO2 build up in the fish room, but since bringing the skimmer air input from the outdoors hasn't fixed the probelm I'm confused to what it could be.
-TK

[Randy Holmes-Farley]

My best guess is that you have a pH measurement problem as opposed to a real drop that large, unless you added something unusual.

How are you measuring pH?

[TacoKing]

I've been using a Aquacontroller II to monitor the PH. I tested the probes a few weeks ago (prior to the drop) and everything seemed fine. I guess it probably would be a good idea to get some calibration solution and calibrate everything just to be sure.
-TK

[Randy Holmes-Farley]

Yep. :)

Grocery store borax can also be used to check it:

http://web.archive.org/web/20021015005420/www.animalnetwork.com/fish2/aqfm/2000/feb/bio/default.asp