LOL.. Reefwars.. too fast for me. 1Big,, I'll leave you to the pros... I'm still a newbie.
Half of the fun of this hobby is the learning curve. You're in the right place coming here.

if the tank is around 4yrs old i imagine the cyano is from you scrubbing the rocks of algae, stuff tends to build up after time in the rocks and that all would have been released and the algae itself then too.


if the flow is too strong in your tank then that too isnt good for softies and they will shrink up and die.

if light is to strong then they will shrivel up and melt.

pretty much everything has melted away within a week, toad stool, xenia, brain, colt. only thing that has survived is a mushroom.

check your temp reguraly?? sounds almost like they cooked.....not surprised the mushroom survived lol :twised::twised:

I keep my tank at 80, I'm leaning forwards phosphates as well. As the saying goes the solution to pollution is dilution. The system wih the skimmer and sump is probably between 90-100 gallons, I was think of doing water changes of 25-30 every couple days for a week.
Any objections, or better ideas?

Ps thanks to all of you for the info.

I'm all for water changes to some extent, but I think you'll have diminishing returns after a while.. and your system is fairly large.
If I were in your shoes, I would do the usual water changes (about 5-10% per week) and find a solution to the phosphates: GFO, biopellets...

even just 2 x 20g water changes in one week will be fine. that ol saying never turns ya wrong. the large water changes of 20g wont hurt its what i do weekly on my 90g with 75g sump so if you do 2 say with a few days apart will be plenty.



to me phosphate is the one thing that i absolutely have to keep in check, i wouldnt dare run a tank without gfo although i have many many times but after doing it on the last few tanks it works and if you start it early it works very well.

still though i dont think high phosphates would melt all your softies in one week...... all of a sudden........ it would take something stronger, maybe from the scrubbing of the algae?? stuff tends to build up in the rocks that can get nasty over time, powerheads miss it and flow cant reach it so untill that day the brush hits it its sitting there rotting and waiting to be disturbed. softies and leathers absorb alot of whats in the water, nitrates they can handle in small amounts but larger amounts and not so much.

Make sure that your salinity is accurate. Best to use a calibrated refractometer to test it. The plastic hydrometers are horribly inaccurate. I have seen them out by .003.

If your Alk is low(< 7.3dKH) it can cause problems.

Phosphates will cause problems for corals if they are too high(typically >0.5mg/l and you will get problems, especially trying to adapt new corals).

As for Phosphate removal I would recommend Foz Down. I make and use Foz Down so I know it works and is safe. It is cheaper and easier to use than GFO or pellets.

Here is a link http://www.oceanfreshaquarium.com/foz-down/

You might want to try adding some Iodine as well.

Water changes are one of the best ways to maintain a healthy environment for your animals.

Cheers,
Tim

also you might want to test for copper. I recently put Kent carbon in my tank and all my xenias (3 varieties) melted in few hours. It's not the carbon because I was using Seachem Matrix carbon before and I had my xenias thriving for the past 2 years until my tank was contaminated by copper.

Problem is, there might still be a lethal level of copper in your tank and that would be lower than what the commercial tests can detect. Anyway it is a good start to test for that anyway.

I know it was mentioned before but i lost a massive colony of xenia and colts just as you described 'melting away' in a very short period of time. Mine was caused by a massive increase of phosphates because of a new container's I started using for ro and salt mixing. I didn't clean them properly before using and poof they dissapeared in less than week.