I really appreciate everyone that gave me feedback.
Here's some answers to your questions on equipment, maint., water params, etc.
* Alk: 8 / Cal: 450 / Mag: 1300 / Ph 8.1 / Nitrate: 5 / Phosphate: 0.02
* 20-30gal water changes every 2 weeks NOW (never did before which might have started this).
* Running GFO in a nice reactor in the sump. I try to keep it fairly fresh but I might have to start switching it out more frequent now.
* I do Vodka dose. Been dosing for years no issues. Maybe Nick has a good point. I'm going to look into vinegar, Red Sea NO3
O4-X Nitrate & Phosphate Reducer, etc. (thoughts on this?)
* Tank is pretty packed with coral and fish. I do have a starry blenny that munches on the algae, 2 yellow tangs and 1 blue tang....plus other misc. guys.
* I've been running my own RODI unit in the garage and I keep it at 0 TDS... at least that's what the meter is telling me. I need to test it manually though. This could be an issue?
* 40 gallon sump where I use a BM220a skimmer (to me it's a beast rated at 400 gallon). GFO reactor. Running socks. Nothing else in the sump. No chaeto or anything else. No room with the skimmer and sock.
* Running (6) 80w T5s. ON at 2pm / OFF at 10pm. 2 bulbs come on at a time and turn off at a time so all 6 bulbs are on together for 7 hours. Maybe to long?
So what do you guys think about trying Dr. Tims Waste Away, Algae Fix Marine and/or adding a Sea hare? Do you think any of these would really make a big difference? Honestly if i can't get this resolved soon I'm doing something drastic like starting over. The tanks been running pretty good (never perfect) for 5 years plus but now I'm stressing over it everyday lately and it's not much fun anymore.