Help! Classic ATO failure but really weird results.

[GoodKat]

I am at a complete loss here. Last night my Innovative Marine ATO controller failed in the one position and pumped roughly half a gallon of almost fully saturated Kalk water into my ten gallon tank. I add 1.5 teaspoons of Kalk to ATO res and the ATO res in only 1 gallon. 

The PH skyrocketed so I quickly did a 50% water change. However! Calcium plummeted from 430 to 390 and my ALK dropped way way down from like 7.5 or 8 to below 6 dKH.

I refill my ATO res once or twice a week, so the solution is never in there long enough to solidify. 

Can some help me understand what is going on? This is the opposite of what I would expect. I am scared 

[MrObscura]

Did you test after the water change? And what levels did your mix water mix to? 

 

Also I think the cal and Alk levels raised by kalk take a little time for the chemical reaction to occur. At least the Alk part, as the hydroxide needs to react with c02 to become Carbonite(alk). 

 

On a side note I highly recommend the ice cap ato. It's a dual optical system with external on/off for 120 bucks. 

[Tamberav]

My guess is precipitation from so much kalk being put in. Be sure to clean your pumps.

[empresto]

+1 to precipitation.  That would be the most likely culprit.