help for high alkalinity

[gws294]

Randy,
I hope you can help. I'm new to the hobby. Just setting up a 72G tank with 20 G sump and 20 G Refug. It's been up and running for about 2 months... Things got out of wack last week so I checked the alkalinity and dKH = 24!!! (Ca = +/- 350: Mg +/- 1300) I've been doing 20% water changes every day or so since and I can't seem to get the dKH below 16. I'm using ro/di water and IO.

Any suggestions?? Thanks for your help.

Geoff

[Boomer]

Any suggestions??

For now just one, are you usng a Red Sea test kit ?

[gws294]

Boomer,
No, I'm using a Salifert test kit and when I check my makeup water, it test ok at about 8.0 dKH. I also thought that I might be using the test kit incorrectly, but I've double checked and seem to be using it according to directions.

[Randy Holmes-Farley]

Assuming those values are right, I'd supplement just calcium with calcium chloride until the alkalinity drops to about 11 dKH or less.

This article will descibe the process:

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

[gws294]

Randy, Thanks for the info... the article really helped to clarify the different relationships. Just a side note... your contribution to the hobby by way of your technical articles is fantastic for beginners like me. Thanks so much.

I checked my alkalinity with another test kit and guess what???? My original Salifert kit must be really messed up (has been measuring between 16 and 18). My carbonate alkalinity now measures around 11 (with the other kit). I seem to have been going around in circles for the past week for nothing.

I picked up some Ca chloride (Kent's Turbo calcium) and have been adding it as directed... about a teaspoon at a time (for a 100G system)... I still don't see a substancial increase in the Ca levels (hanging around 330 or so). How much should I use or is safe to use? How often should I add and test?

Thanks so much for your invaluable help! Merry Christmas.

Geoff

[gws294]

As a followup... I checked with the "Calcium Calculator" by M. G. Kedemani and is said to add about 18 teaspoons... how's the safest way to add that?

Thanks again

[Randy Holmes-Farley]

My original Salifert kit must be really messed up (has been measuring between 16 and 18). My carbonate alkalinity now measures around 11 (with the other kit). I seem to have been going around in circles for the past week for nothing.

Sometimes people read the Salifert kit backwards or sometimes use the wrong volume. You might check with Habib in the Salifert forum if you suspect a problem.

It does take a lot of claicum chloride to raise calcium significantly. I'd dissolve it in fresh water and add it all at once to a high flow area away from corals.