I have had my 13 gal tank since Jan/Feb. Over that time the alkalinity has slowly increased to 7.9-8.0. Ten days ago it was 7.9. I just measured twice with my Salifert test and it appears to have dropped to 6.7. Why would this happen and will having it this low cause immediate problems? pH has remained at 7.9 - 8.0 since the beginning. Soft corals only. No fish. The only thing that has changed is that I began dosing Nitrate a little over a month ago and a turbo snail may have died recently. I was also out of town for a week last month, so my corals did not get fed as usual.
Amm - 0
Ph - 8.0
nitrate - 15
Phos - .015
Alk - 6.7
Amm - 0
Ph - 8.0
nitrate - 15
Phos - .015
Alk - 6.7