Well I started dosing i-herb vitamin C this week, and have noticed a couple of unwelcome changes. I cannot be positive that these are from the vitamin C, but I want to post them here in case others have input on the situation. Not saying they are definitely due to VC, but the only other change that happened this week was a ~15% water change, and changing the halide bulb over my sump from 10k to 20k.
1. Increased cyano growth. I had one small spot of cyano in my display tank, and none in my 150g stock tank (sump/prop tank). After a week of dosing the cyano spread to cover roughly 3x the area it previously had and showed up in several spots on frag rubble on the rack in my sump.
2. Completely retracted polyps in 2 digitatas, partial retraction in 1 other digitata and 2 encrusting corals. All of these corals had been growing well for the past 1+ years with no problems. Now I'm seriously concerned I may lose the pink (nicest) digitata and I'm going to transfer it to another reefer's tank tonight. Its polyps have been in for 4-5 days now and the coenosteum is looking poor.
I have 40+ different montipora in the system, and it is only a handful that are showing these symptoms. Stylos, acros, seriatopora, and zoas all seem fine. Could just certain varieties be ultra sensitive to the increased carbon in the system? What are everyone's thoughts? I stopped dosing VC 2 days ago and siphoned out most of the cyano and some of the corals with poor extension seem to be improving. It could be that the water change was a shock to the system, and it's just stabilizing now too.
What are everyone's thoughts? The dosing level was 1/4tsp/1x per day in roughly 210 gallon system (accounting for dsb in sump, and LR). It doesn't seem to me like such a tiny amount should have an effect though. All other parameters are normal.
-Tim