My alk is running above 13. The sup I use for Ca is Kent turbo Ca. I don't use a buffer because my alk is so high. I don't understand all the products just want to make it go higher. What can I do to lower alk only??
If your calcium is 420 ppm and the alkalinity is above 13 dKH, then you must have been adding some sort of alkalinity supplement in the past (unless you are using Seachem salt which has artificially high total alkalinity due to excess boron).
Whatever it was that you added, I'd suggest not using any more of it until the alkalinity drops below about 11 dKH.
That said, I don't see any real problem with the alkalinity that you presently have. I'd just monitor it and let it drop on it's own, as it surely will. Keep adding the calcium when it drops below 400 ppm.
I took some test this moring.
PH 8.0
Ca 420
Mag 1170
Po4 0.03
KH 15.7
ALK 5.60
S.G. 1.025
All I add is tropic marin Bio-cal ( It does not say any thing about adding alk) I use a salifert tests for all. I use RO water. Do you think the relationship with the PH and ALK is ok or should I worry? Thanks agian for taking the time.
Well, you've been burned by one of the most poorly described products in this hobby: Bio calcium. It does supply alkalinity, though it is not entirely clear how much. I'd stop using it completely.
I think everything will be OK, and I'd just let the tank alone until the alkalinity drifts low enough to need more of some sort of alkalinity supplement. I usually recommend 2.5-4 meq/L (7-11 dKH) for alkalinity.