stand alone kalk use caused hig ca and low alk

[711reefer]

80 gallon water volume reef
very light bio load
30 gallon ato barrel filled about 20 % of the way with 1/4 tsp per gallon kalk saturation
for about a month I was using a small amount of seachem 2 part daily to keep alk at 8 and ca at 400

I decided to stop dosing 2 part since system was pretty stable. after 5 days of kalk alone my ca went to 510 and my alk dropped to 6. corals are not happy at the moment. I did stop using kalk and started using the alk part of the 2 part to help bring alkalinity back up slowly and hopefully drop the ca

any reason why using kalk alone would cause such a drastic change in my params so quickly ?

 

[Randy Holmes-Farley Verified Community Expert]

Because you are hardly adding any. Even saturated limewater at 2 tsp per freshwater gallon only adds 1.4 dKH of alk (and the balanced amount of calcium) when added to replace evaporation of 1.25% of the tank water volume daily. You might be adding something like 1/8 of that, or only 0.2 dKH per day.

If calcium rose, that was testing error.

 

[711reefer]

thanks for the reply. makes sense if I was using a low saturation kalk for make up water however, I tested the water 4 times to confirm my ca readings. each time I was at the 500 mark. I also mixed up some fresh saltwater and my readings were 405 for it. so weird

 

[Randy Holmes-Farley Verified Community Expert]

thanks for the reply. makes sense if I was using a low saturation kalk for make up water however, I tested the water 4 times to confirm my ca readings. each time I was at the 500 mark. I also mixed up some fresh saltwater and my readings were 405 for it. so weird

I'm not sure where the issue lies, but it wasn't limewater raising calcium a lot in a few days.