kalkreactor low alk

[sheepdawg]

I've been running a new reefgeek kalk reactor for about a month in my mixed sps/lps 75 gallon. I've noticed that the CA has been consistent at about 420 but the alk will drop significantly. I've raised it from 7 to 10dkh with baking soda and in about 2 days it will drop back down to 8dkh. It is my understanding that kalk should keep the CA and Alk balanced. Anybody know what I'm doing wrong. by the way PH has been around 8.2-8.37.

[Randy Holmes-Farley]

If the alkalinity drops, then the reactor is not adding enough calcium and alkalinity to meet the demand. Alkalinity always responds first to under dosing.

The reactor may not be dissolving enough lime to saturate the effluent, or it may just not be enough even when saturated.

How often do you stir it?

Do you have a conductivity probe to measure the conductivity (potency) of the effluent?

You might just need something like a two part in addition to the limewater.

[sheepdawg]

Randy, I have it set on a timer to stir every 4 hours. I've checked the solution with my PH monitor and it was reading at 12. Perhaps I need to turn up the canopy fan to increase the evap rate.

[Randy Holmes-Farley]

pH is very crude, and not a good way to judge, but if accurate, pH 12 suggests it is far from saturated. Saturated limewater has a pH around 12.5, and a difference of 0.3 pH units is a difference in potency of a factor of 2.