Possible tank crash

[scooterscooter]

First some background information. I have a 15g with two clowns and a bicolor blenny. Also, a duncan, zoas, palys, hammer, and xenia. A sand bed with fine sand that is about 3-4 inches deep.

 

So last week I decided to do my 2.5g water change and decided that it would be a good idea to mix up the sand to see if it would solve the cyano problem that is covering bottom. The next afternoon I noticed everything had closed up slightly and the palys had a ring of something growing around the mouths. It was the same color as what was growing on the sand.

 

I did a couple more water changes and tested for ammonia, nitrite, nitrate, pH, and started running phosguard. Today I have also started running carbon. All the params came back testing close to 0. pH of 8.

 

Everything I have read has said that crashes happen overnight or in the span of three days. I have gotten some of my zoas to open up and the duncan has started to show some life. The palys are closed completely, but no signs of strange growth on them.

 

Does it seem that my coral is coming back and my tank isn't crashing?

 

Also I am thinking about totally cleaning my tank/sand and dipping all my coral in iodine in the process. Good idea?

 

Thanks!

[rengb6]

Let everything settle. Stirring up the sand can irritate zoas. I used to stir my entire sand bed during every water change and the zoas wouldn't open up until five or six days later when the water was no longer cloudy. You might try stiring just sections of your sand bed from now on to avoid that. I ended up removing the sand all together and my zoas opened up fully and stayed open during lights on.