need help

[bb21375]

i have white film or maybe its foam covering the top of my water. does anyone know what it may be i did a 20 percent water change but it's still there. how do i get rid of it. i want it to be clear.

 

[nero]

give us some descriptions first...
water quality?
how long has the tank been set up for?
what are the inhabitants?
sand or crushed coral?
did you just stir up, or add new sand?
i think all of these will help get some good answers

 

[viper_930]

Just dissolved organic material gathering at the top. You can aim a powerhead towards the top to move it around and get it down into the water, or get a prefilter/surface skimmer for your HOB protien skimmer (if you have one).

 

[bb21375]

no i didn't stir it up but my tank has been up for several months now and the cyle is complete. although i did change the substrate form crushed coral to live sand maybe a month ago. could that be the reason. the crushed coral could have done it when i remove it. the water looks cloudy only on the top floating.