Just read this entire thread. Some great info. I think it's safe to say my tank has a bad case of dino's... at first I thought it was a mini-cycle from some new dry rock that I added to my established system... after several months of it not going away, I realized this likely wasn't the case. So I instinctively tried a few things (before doing proper research)...
1. Aggressively siphoning the sandbed during my weekly water changes... it would come back within a few hours.
2. I increased my flow with better/more powerful powerheads... no success.
3. I thought it was possibly old T-5 bulb's that I had, so I used this as an excuse to upgrade to LEDS... no success.
4. Boosted the hell out of my CUC - no success, except for killing tons of cerith's.
5. Lights out for 3 days. No success.
I am strict about 10% weekly water changes and only use RO/DI water. All of my RO's filters/membrane have been replaced in the last 2 months. TDS reading 0. Nitrates are undetectable but my Phosphates seem really high... possibly due to overfeeding, which I have been a lot more careful about over the last few weeks. Thriving fuge full of Chaeto.
New plan of action:
1. Reduced feeding.
2. No water changing for the time being, but using a filter sock to siphon sandbed/dino's out manually... replacing the water back into the tank. Doing this every other day for a week or so.
3. Running filter sock through my sump, cleaning every 1-2 days.
4. Running skimmer wet, cleaning every 1-2 days.
When done with this process:
5. Lights out for 5 days with blankets over the tank, sump, and even covering my clear hoses to/from the chiller, etc. Perhaps another siphoning after this 5 days is up??
6. Dosing Ultra Algea X... I am normally apprehensive about any kind of chemical dosing but there seems to be a lot of reports of success with this product, and frankly, I am tired of dreading looking at my tank and am willing to go outside of my normal comfort zone: