The easiest way to avoid getting algae is to not use tap water. Find a good RO/DI unit and make your own water.

thanks guys for help!!!

my tank is 29G w/ HOB CPR BAK PAK 2 protein skimmer , T5 4bulbs, 40pound sand, around 15 to 20 lbs liverock, two clown fish, 2 yellow damsel, 4 hermit crab, 1 cleaner shrimp and 2 snails my is tank is 4 weeks right now!!!

how to prevent a algae in salt fish tanK?
 

here my picture!!

Was the liverock cured or uncured when you added it? You may need to check ammonia. If any is detectable you will want to do small water changes.

the amonia was ok and liverock is ok too!!! no water change yet!!!
thanks!!

IMO from your tank picture there isn't very much "bad" algae or very much algae at all with the exception of the regular diatoms, but do definitely get in a habit of doing water changes, either once a month or once every two weeks. I've been using tap water with prime for several years with little problems but it was for my seagrass which helped absorb most of the excess nutrients in the tap water, Using RO/DI will definitely help control the algae. How often do you feed, and what do you feed?

hi jeff
 

i feed them twice a week a frozen food!!!

thanks

I feed daily. Twice a week is barely enough for most fish. Some fish such as Anthias have very short intestinal tracts and need to be fed two or three times a day. Smaller portions once a day would probably suffice for you, just be sure you are feeding the fish instead of the tank.

same here most of my fish are fed very small amounts everyday and i always try to give them a variety in food.if you want your fish to be healthy and have all the colour they can you need to feed them a variety of all the things they can get in the wild:)

krill ,mysis , brine, nori, flake and blood worms are my regular food and every now and then ill feed fresh seafood like shrimp or crab:)