Reef Saver from BRS
Thanks for answering my questions and confirming my suspicions...
So I have the same exact rock and as mentioned earlier, dealt with the looking growth. It came on when my tank was about 4 months old and didn't go away until when my tank was almost a year old. I also had phosphates and nitrates at 0 and would only have trace amounts after not changing my water for a few weeks. I tried treating it multiple times with Dr Tim's Refresh and Waste Away and did little to nothing. I tried cleaning my tank more frequently and did 15-20% water changes each week and the problem would only seem to get worse.
I googled the heck out of this and went through dozens of threads on multiple sites trying to figure this out. I first started chasing after the "white slime" and bacteria threads... but it didn't match up with what I had in my tank. Eventually figured out that it was chrysophytes, or golden hair algae. As I did homework on chrysophytes, I started noticing three common themes with most people dealing with chrysophytes:
1) Most people had newer tanks (a few had older tanks but mentioned that they recently had done a big cleaning or made big changes to the tank)
2) Everyone said their phosphates and nitrates were at or near 0
3) Almost every single person had dry rock, with BRS/Marco mentioned the most
From what I gathered, it seems that brand new BRS dry rock will absorb phosphates and nitrates... I came across one thread where the OP did an experiment by dosing his tank and it was surprising how much the rocks can absorb. Some explained that this is common with new tanks (some called it "new tank syndrome") and can also happen if you're keeping your tank too clean. All of these explanations are common in that phosphates and nitrates are at or near 0.
So how did I ultimately fix mine? First, I physically removed as much as I could and siphoned out as much as I could while scrubbing them off the rocks and equipment. I then blacked out my tank for 3 days (with corals and fish and everything in it). After the blackout, I ignored my tank maintenance:
- No water changes for about 8 weeks
- Changed filter socks out only when they started clogging up
- Didn't scrub the rocks, but still cleaned all glass
- Fed my fish and corals a bit more
Yes, my tank got pretty ugly for a little while, but it was totally worth it. Over the past 6 months, I've only had a few small patches for a week which went away on its own. If you give this approach a shot, hopefully it'll work for you too.
