Help

[Robert D'Amaro]

I have been battling this for months. I have tried 3 day blackout (x3), red slime chemiclean (x3), manual removal (every weekend) added a uv sterilizer. parameters are all normal and as far as I know never got out of whack. Nitrates 1, phosphate. 01, calcium 460, alk 9, mag 1380. Tank is 8 months old. 12 corals all look absolutely fine. 9 fish 2 shrimp snails etc. At this point just wanting to identify. it is a dark brown very fine growth. Some on rock but almost all on gravel. I was reading some Randy Farley articles about phosphate and one says the gravel could be acting like a phosphate sponge so I am thinking about removing it all to see it it helps. Any thoughts or help would be appreciated.

 

[R.Weller]

I'm only in year 3 of reefkeeping, so for what it's worth, I suspect you have dino vs. cyano.

We get this as well, & it happens each time we upgrade. They are likely feeding on silicates that are leaching into the water column. This comes from rock, gravel, top-off water (even some RO) & I read somewhere from the silicon used to seal the glass panels but I was never able to verify this.

In our experience, it goes away in time (6 - 12 months) as they will eventually starve provided they are not being fed from your top-off water. I never tried any chemical agents or black-outs, but there are numerous threads on the topic. We are in month 3 of our upgraded 300gal display, & we added ~100 lbs of mined dry rock so it's part of our struggle right now (around 400 lbs total). We had them in our first 60gal, then in the 220gal & now in the 300gal. We leverage biological filtration heavily (algae scrubber & oversized refugium) along with a skimmer. No GFO, carbon, UV or filter socks so it's something we just live with as the system matures. Every few days I use a spare wavemaker to blow around the sand bed & the skimmer removes most of the suspended particles.

No magic beans here...just patience.