HIGH dkH

[JSB5776]

Hi everyone,

I appologize for not searching as I imagine this topic has been discussed frequently, but the search has been blocked all day.

My dKH is about 18-20 and I need to get it down. I have read of dosing with seltzer at a rate of 1 Oz per 20 gallons per hour to reduce it. Is this the best method or should I try to raise Mg levels?

Is a dKH this high harmful? I'm feeling it is a some of my hard corals are now bleaching rapidly.

What would cause it to get so hi? I have been dosing kalkwasser at the concentration of 1 tsp per gallon every other day in the top off water for a couple weeks.

pH has been a little low, so I have been rasing it occasionally with Seachem reef buffer. Its about 8.1-8.2 now.

Should I do a large water change tomorrow?

Thanks for your help,
Jeff

[Randy Holmes-Farley]

but the search has been blocked all day.

Not if you are a Premium Member.


My dKH is about 18-20 and I need to get it down. I have read of dosing with seltzer at a rate of 1 Oz per 20 gallons per hour to reduce it. Is this the best method or should I try to raise Mg levels?

Neither of those will help. Adding carbon dioxide (seltzer) has no impact on alkalinity, and normal magnesium levels allow it to remain in solution as opposed to precipitating as calcium carbonate.

It is the addition of the reef buffer that is pushing up the alkalinity. It is not a suitable way to raise pH, and ends in excessive alkalinity. So do not add any buffers.

pH is best raised by aeration with fresh air, and limewater:

Low pH: Causes and Cures
http://reefkeeping.com/issues/2004-09/rhf/index.htm


The alkalinity will come down on its own as long as you maintain normal calcium levels. This article has more:

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