Kalkwasser RTN

[SMG91]

3 days ago I added fans above my 75g tank to combat high temperatures. The tank was maintaining 8.35-8.40 diurnal pH swing with 4000ml of fully saturated kalk dosed through a kalk stirrer. With the fans added over the tank, temperature was now in check and I used the opportunity of the increased evaporation to increase my kalk dosing. I ended up increasing to about 7500ml and my diurnal pH swing was now 8.58-8.61. Per my Trident Alk, Cal, and Mag stayed very stable through the increase of kalk dosing.

I came home yesterday afternoon to my tank full of acropora RTNing.

I am trying to pinpoint what happened. I sent out an ICP, but my question is could the increase of hydroxide added to the tank play a role in the RTN event or the .2 increase of pH over 2 days add too much stress?

Thanks!

 

[Randy Holmes-Farley Verified Community Expert]

I would not be convinced the pH caused the RTN when you went from 8.35-8.4 up to 8.6, but I also cannot claim it wasn't related.