I'm pretty sure the cyano chokes the tissue. I'll try adding more flow. And ok I will!!! ;)

You don't necessarily need to add more flow (though I'm not sure what kind of flow you have), just tweak it. Move the power heads around around until you get a good flow pattern. Toss some food in the tank to see how the flow is moving around (your fish will love it!). I spent an hour doing the same last night and this morning one of my colonies that had been looking blah for months had crazy polyp extension! Just gotta find that sweet spot.

I have the Mag 6 return and 2 koralia 550gph. One is essentially stuck on the back glass... Can't take the backing off, actually bent a scrapper trying.

The valonia algae can be taken care of from emerald crabs as I had the same issues as you about a few years ago, the cyano is abit of a battle, do more waterchanges and try to reduce feeding, you can also add bright wells (slowly) mb7 to help start another bacteria culture to out compete the cyano. I tried numerous approaches to rid cyano from sugar dosing which is a carbon source to manual removal. I finally caved and used medicine the cyano disappeared but the clams didn't like it and in turn lost all the clams as a result the tank turned into clam chowder and I lost 90% of my sps. $6000 in livestock down the drain.

Not trying to scare you but from experience will never use any Meds on my tank ever again. Try the filter sock and turkey baster technique to alleviate cyano or even adding mb7 which should out compete the bacteria.

Good luck!

Every emerald crab died within a day for about a year, the LFS switched supplier and we now have 4 alive and well and chowing down the past month :) so the Valonia isn't really worrying me especially since I decided that scrapping the stuff off would probably not make things any worse than they already were. The cyano is better but I'll be doing another 3 days lights out in about 2 weeks to bring it down more. I'm doing about 15-20 gal wc weekly right now and that"s after blasting all the cyano off so I can siphon it out as well as as many bubble spores as I can get.
Thanks!

Parameters: last night
Specific Grav 1.025
PH: 8.2
Ammonia:0
Nitrite:0
Nitrate:0
Phosphate:0
*DKH:7* lowered from 9 in a day
Calcium:420
Mag: 1200

Are these the ideal parameters for these?
Calcium 380-450
Alkalinity 7-11 dKH
sg = 1.026
pH 8.1-8.3
Magnesium 1250-1350 ppm

Calc seems low but I've always kept mine high for all the sps...
Never had a problem with using chemiclean for cyano.
Although in your case the nutrients released would require heavy skimming and water changes. Do you grow chaeto or run pellets to help with extra nutrients?

I was debating using chemiclean but I just got a Mandy and I heard that it will essentially wipe out my copepod population so that will really be a last resort. A few months ago chaeto was running rampant in my DT which I'm thinking might have to do with my issues now since I ripped it all out. I don't seem to have much extra nutrients though. I feed once a day either pellets or half cube of mysis.

cheminclean don't do a thing to the pod population. It does not do a thing to anything else but cyano.

I used it from time to time to make my water crystal clear. It just make your skimmer go nuts so be carefull with this and sometime you have to remove the skimmer cup and let it run like that just to keep the water oxygenated.

It is not good to stop the skimmer if you don't have to so removing the cup often is enough to be able to still run it.

If you have that much problem with cyano, I don't beleive that you have 0 nitrates and phosphates....pretty much doubtfull.

Use the Redsea nitrates and phosphates test kit and see the result...you probably have a lot more than you think.

the cyano don't stick on healty coral. If it stick on your birdnest it is because the flesh on it is already dead and gone, maybe from something out of wack with your parameters? could be copper if you keep loosing your crabs?