Beating sand dwelling(amphidinium ) Dinos. . . I think this did the trick.

[a.t.t.r]

I Have triend black outs , UV, silica and po4, copepods, phyto. It comes back next day.

This time I Installed my small UV. I gently brushed any large patches of the algae on the rocks and sand (amphidinium). Turned out the lights for 48 hour.
I do small daily waterchanges (20 gallon tank 1/2 gallon a day) with the new water having massive ammounts of po4 and silica added.
I set my led lights to slowly ramp up from 0 percent to 80 percent over a total of twenty days with the theory that this will hopefully allow better competition of desirable surface algae.

We are about a week in and so far so good. I hope I didn't speak to soon but I think this is doing the trick.

 

[a.t.t.r]

I turned off the UV sterilizer Two days ago due to some hatching seaslugs in the tank. Lights at back up to about 50 percent power. Still no visible signs of Dino’s except a couple under microscope samples.