Low calcium

[MoshDmM5]

So I’ve recently noticed that my corals haven’t been doing so well and haven’t been as happy as normal. My tank is a 90 gallon mixed reef with just two clowns after a wave of ich that wiped everything. Tested my calcium last night and it came out to 120ppm but my alkalinity was 7. Tested around the same time today a few hours after doing a 10% water change hoping to boost the calcium with fresh saltwater but it came out at 95ppm today and my alk at 7.5. PH was 8.2 and now it is 8.0 and my magnesium is at 1320 so it’s not low enough to be causing the instability of my calcium and alkalinity. Help?

 

[mdb_talon]

It seems highly unlikely that is an accurate number. Especially with alk being in a reasonable range. I would try a different test kit before doing anything else.

 

[SantaMonica]

And if you don't have another test kit right now, you could just dose a little CA to see if the test goes upwards.

 

[MoshDmM5]

It seems highly unlikely that is an accurate number. Especially with alk being in a reasonable range. I would try a different test kit before doing anything else.

I used a salifert calcium test kit. I’ve had no problems with them before. I don’t have another test kit but I did dose some CA last night and it still dropped to 95 today.

 

[mdb_talon]

Another sign that it is an inaccurate number. Test a freshly made batch of salt. If it shows a very low number then your salt mix is bad or your tests are wrong.