Here's a 10-day update after starting the 'dirty tank method' a second time. Short story: lots of good progress. (Knock on wood)Thanks I am giving it a go. And my big CUC and my 5 herbivorous fish should all be pretty fat in a month! Just installed the temporary UV setup in my DT on low flow (~250 gph). Fingers crossed
Starting a couple months ago, I developed a bad prorocentrum-dominant dino problem (microscope confirmed) in my 300G mixed reef. First time in 10 years that I've had noticeable dinos. After trying a few different remedies, I resorted to the dirty tank method. Although this didn't eradicate the dinos, I believe it at least stopped the infestation from getting any worse. During the first couple weeks of this experiment, I couldn't get my NO3/PO4 above 3 ppm and 0.02 ppm respectively (Hanna)---so I started modest dosing of Seachem Nitrogen and Phosphorus Flourish. Unfortunately, all this led to a huge algae/cyano outbreak which itself was bothering my corals and my mental health. (However, my measured nutrient levels never rose---the algae and cyano sucked them out of the water.) Therefore, I abandoned the dirty tank method and started doing an aggressive series of water changes, started using GFO again, dosed Vibrant and Microbacter7 (not at same time), and did a big refresh of my CUC. Algae/cyano started receding after a week or so.
Then I had a very bad ostreopsis-dominant dino outbreak on Wednesday 5/26 a day after a big water change. Brown stringy goop covering everything. Corals were really suffering. On Thursday 5/27, I re-plumbed my UV to be on an independent closed loop in/out of my DT and put it on low flow (~250-300GPH). No more water changes and removed GFO, but still using carbon. Regular feeding (2 cubes spirulina brine shrimp, 1 tablespoon Omega One Veggle Kelp flakes, 1 teaspoon reef roids, 1/3 nori sheet, and nighttime dosing of red sea reef energy AB+). No supplemental nutrient or Vibrant dosing. One dose of Microbacter7. PLENTY of daily turkey basting of the and rocks---but intentionally not the Loc-Line returns or overflows so I could use growth there to monitor progress. Regular skimming and regular changing of felt filter socks.
The outbreak got worse over the first couple days, then stabilized for a couple days. Five days in, I thought I could see an improvement but I figured I was imagining it. Eight days in, the brown goop was largely gone from Loc-Line and overflows. Yesterday, just about all the brown goop was gone. I still have prorocentrum dinos in numerous spots (lots of bubbles, but little goop), but the ostreopsis has largely vanished.
My NO3 hasn't risen above 5 ppm and my PO4 hasn't gone above 0.05 ppm. I do have a cyano outbreak now and plenty of film algae on the glass, etc., but no other troubling algae as of yet. I'm going to stick to this hands-off approach for now and carefully monitor my nutrients and watch algae/cyano. If the latter gets bad, I'll do a 5% water change and see what happens after a couple days. Despite my doubts as to the increased efficacy of having the UV closed-looped in the DT, that really seems to have made a difference---at least with the ostreopsis. I'm also wondering if the previous Vibrant use was one of the culprits behind my dino problems. Jury is still out on Vibrant though.
Sorry for the long posts on my dino battles. However, I hope these chronicles will be helpful to someone someday.