What's going on?

Hello,
I just signed up to this site because I'm having trouble with my tank and I do not know what to do, so I'm hoping someone can help me!
I'm new at this hobby and really want my tank looking nice!
I have a 20 gallon tank that has been running for a month (used to be 10 gallon that was running for 2 months until I went bigger) with a Corallife Aqualight HO t5. As of tonight I only have a blue damsel, pulsing xenia, an sabae anemone (that looks like its gonna be a goner) and two zooanthids. This morning I used to have a clown and goby but sadly both of them did not make it. My rocks are covered by dark brown slime (i think) and my glass is constantly covered by green dust no matter how many times I clean it. I checked my water and the ammonia was the only one just a tad higher than where it should be. pH was good, temp was fine, nitrate and nitrite was ok as well as the phosphates.. Help!

 

well first things first dont get too stressed these things happen to everyone. It looks like Dinoflagellates to me. i dont know much about it but im sure the good people on this site will fill you in on how it is caused and how to get ride of it.

 

Welcome to 3reef.

What is your water source?

Is that regular rock commonly used for SW tanks?

Looks like 1st off you need more flow in the tank, increase surface movement.

What type of filtration do you have?

How much are you feeding and what?

After increasing flow I would take a turkey baster and clean as much algae off as you can. Once it begins to settle I would do a water change with fresh SW made up of RO/DI only. I would repeat doing 5 gallon water changes every couple days.

I would not expect the corals or anemone to make it and I would not buy any more fish or corals until either the algae problem resolves or the diatoms fade away.

You can run some phosban as well.

This probably will not resolve over night or few weeks. If you do not get a handle on the brown algae in a week or 2 re-post.

 

Thanks for the input!
Water source : premixed salt water from petco, for topoff I use distilled water
Rock: Live rock from lfs and base dry rock from petsmart
Powerhead: 1 Koralia 240gph
Filtration: hang-on back Tetra 30-45 gallon
Feeding: daily (1/4 of a cube) brine shrimp

Do you have any ideas on what this could be?

 

I suspect it's Diatoms that will fade as the silicates are used up. A mixture of Cyanobacteria as well, increased flow should help as well as water changes.

Consider buying your own salt mix like Instant Ocean, you can get that at Petco and bottled RO/DI or distilled if that is all you can get. Mix the SW over night and check the SG prior to water changes.

I would also buy some more base dry rock and add a couple more pounds to assist with increasing your biological filter, the HOB tetra will not cut it, adding more rock will help in the long run.

If it does not get better in the coming week consider a complete black out for 4 days with the cleaning mentioned in the previous post.

Get a dry pellet food, a decent brand try that, and feed less for awhile

If you have the values for Nitrates and Phosphates that would also help.