Dying Coarals...?

[tinhorse]

I just came home 2 days ago from an 8 day vacation to find all my corals are closed, along with my green button polyps and xenia and star polyps and my one big hammer looking rather sad... I did a large 50% water change yesterday as nothing was improving and today did another 20%. Fish and bta's look better than ever and only my one small Kenya tree and some of my smaller brown buttons looks to be happy. Mushrooms are also looking terrible. Here are my water tests.
Phos- 0.1 lower than it usually is...
Nitrate - 0.12
Nitrite - 0
Ammonia 0
Salt - 1.025 on my refract and 1.024 on my plastic instant ocean checker
Alkalinity.....? Apparently needs to get another test kit asap.

I'm using reef Crystal's and just the last 20% water change I did yesterday now have ro/di water. All water in the tank including the big 50% change has just been tap with prime and salt added to it.
I plan on leaving the tank now for a week and will see if there is any improvements. Any advice would be much appreciated. I will add pics as soon as I can. Thanks

 

[tinhorse]

Here are pics before I left.

 

[tinhorse]

Here are the corals now....

 

[tinhorse]

A few more of the today pics. A couple green polyps have now opened...majority stilled closed

 

[tinhorse]

It is a 75 gallon with led strip and 2 t5 ho bulbs. Hob aqua c remora skimmer, aqua clear on back with sponge and floss which is cleaned weekly and a few power heads on a 30 second wave cycle. I've had the tank 6 months now and many tanks in the past but not one for 10 years. Previously it had been set up for 5 years and I bought it and moved it in july. Had trouble with PO4 and Nitrates for the first 2 months but everything had settled except for some hair algea which I plan on using fluconazole on when I get everything back looking like it should....

 

[carguy4471]

I am a pretty new reefer so please take the following with that in mind.

If this were my tank, since you now have ro/di, I would be mixing new saltwater with ro/di and continuing water changes. I would want to do 3 more 20% changes a few days apart. Depending on the tap water you were using there could be some less than ideal things in the water you do not want in your tank. I nearly killed my fist tank doing this same thing.

As long as your water is good ro/di, and you've mixing your salt up thoroughly, and the water is up to temp, you can't hurt anything with water changes. If something is off that you aren't testing for you are only going to get it out or dilute it. If something is missing you aren't testing for you are only going to add it back in. There's really no down side.

Be sure you are heating your water change water completely up to temp before water changes though. Dropping unheated water into the tank shocks everything pretty good. I heat mine to 82 so that as I transfer it to a bucket and then to the tank it's cooling to around my tank temp at 78. The tank temp has never varied more than .5 deg F with that method.