Ostreopsis - Looking for (natural?) real solutions

[Aqua Splendor]

Hello,
I have Ostreopsis in my tank(s).
One system is linked like so: Display 120, sump 60, Frag tank 120.

I had success with my 35L nano in the past to remove them but in my other system, I'm unable to get rid of them.
I've been through a list of thing that wasn't successful so I'm here to get maybe a new idea and some scientific information (eh never know).

One major problem is it affects my corals, once they reach a certain population they are on top of them and can suffocate them.
Second major problem: Once they reach a certain population everyone is ticked, they release a toxin.

My 2 best solutions so far are these:
-High temperatures (29°C) for 3-day work great but affect the coral too
- Syphonning surface (ricochet making a water change).
- Blackout light work ish but just need 1 to be alive and it restarts, with my system of 3 aquarium it's hard to do a full blackout and/or they seem to be dormant

There's others solution but ineffective:
- UV doesn't matter, Ostreopsis are not floating in the water columns, they mainly stay on surfaces.
- Tried Dino X from FM, never worked and almost killed my entire reef tanks (tried multiple times, and had to stop each time), this product is bad and not reef safe.
- Chemiclean doesn't work (interesting since it affects dinoflagellate in general), but it seems to affect my microbiome.
- Light, using only blue, works but .. doesn't really work, they simply have less energy.
- The parameter of the aquarium doesn't matter, Nitrate High/low, phosphate High/low, they don't care.
- I was hoping for copepods/isopods/etc... but haven't found the real predator yet.. ish
That being said I notice my population of diatom went down and Ostreopsis went up... So I might have read wrong information in the past about this.
I have my eyes on Ciliates
- Carbon, renew... idk what to think about it anymore, doesn't seem to irritate them in my system, but might be due to volume use and flow efficiency
- H2O2 ( Hydrogen Peroxide ) Work ... just not in a reef tank to make a difference (affect too many other life forms)
- Bacteria, idk what to think about it anymore, I can't correlate the effect it does, I think I was wrong in the past about that. Perhaps via side effect...
- My sea Urchin is not a predator, quite the opposite I would say.
- Flow: high or low doesn't matter
- pH: High or low, doesn't matter

I noticed they seem to love a certain mucus on coral. Once I removed one particular coral they disappear from my nano. But in my current system, they are just everywhere.
What I haven't tried because I can't buy them: Mussels, I'm thinking they might be a natural predator, but judging from past experience I don't think they make a difference, at least from my experience, (might be related to the toxin).

So I'm kinda lost on what to do to get rid of them once and for all.

 

[taricha]

- UV doesn't matter, Ostreopsis are not floating in the water columns, they mainly stay on surfaces.

this is generally not true. This type is the most sensitive to UV, and if yours are staying more attached to sand, then you can pair it with a short blackout to force them to swim to seek new habitat.
If these aren't effective (against this type), it's probably because your UV is not functioning correctly.

 

[Relled]

Maybe your flow is too fast on the UV? I ran UV 24/7 for a few months with large daily doses of microbacter clean(not sure if this did anything tbh) then weaned the system off of the microbacter over a few weeks and changed the UV to be on at night only. Cleared up all my nasties but was not an overnight process. Also no water changes.
Ran carbon at a couple of points

 

[Aqua Splendor]

Let's presume my UV is 100% effective and perfectly setup, it doesn't matter, if they don't float and stay on surface UV or not, it doesn't matter. The information about Ostreopsis working with UV is partially wrong, there's misinformation being spread about this, we have to keep in mind there are many genus of them, so in some cases yes it can work but in other cases, it might not. We (collectively) should be careful about spreading generalizing messages like this.

In my case as stated in the first post, it doesn't work for the reason mentioned, unfortunately.

Maybe your flow is too fast on the UV? I ran UV 24/7 for a few months with large daily doses of microbacter clean(not sure if this did anything tbh) then weaned the system off of the microbacter over a few weeks and changed the UV to be on at night only. Cleared up all my nasties but was not an overnight process. Also no water changes.
Ran carbon at a couple of points

Sorry forgot to add to the list and R2R as removed the option to edit first post, but yeah, I used the Microbacter 7 (in combination with other solution) and it didn't work. They come back anyway. So that means whatever is inside is not a predator nor absorbs the same resources. I'm victim of this placebo effect I will admit.
I haven't seen/read the effectiveness of bacteria vs Ostreopsis, documentation is slime and often on the same species of Ostreopsis (ovata).

As for the water change (good point) I haven't noticed the effectiveness of it. There's few of them but that's because I syphon them just before. I can't tell if it's good or bad.

I have the issue of ostreopsis since 3 years so I did a lot of experimentation with different systems, It's the only bad thing I have in my reef tanks so my focus always been on them, the only solution that worked is when I removed one gorgonian, after this, they dissipated and didn't come back. So I assume they had a source of food on with that (mucus?).

I put that gorgonian in other aquariums, at first I thought they were not there, gone but after months they indeed populated with that coral and sure enough, had the same problem in different tank. Proceed to removed that gorgonian, same thing again 1 month later it was gone.

I do have that Gorgonian present in my primary system but its just tiny piece left, a few cm. What I've noticed is after a blackout, one of my acropora bleached on the tips and Ostreopsis goes there and they are killing it slowly. It feel like they feed upon a mucus by stressing the coral. At least it's my impression, could be wrong.