New tank, green algae

[Che]

I have a new 55 gallon tank (eventually a reef tank) with a 20 gallon sump/refugium, 75 lbs of live rock, and a deep sand bed and chaeto in the refugium. The first fish, a green clown goby and a yellow-tail damsel, have been there for two weeks and look great. There are mushrooms corals that came on the live rock and these look great. I had brown diatom at first, but that went away and now I have tons and tons of green algae. I've been using dechlorinated tap water, but just got my RO/DI unit going today. Is the algae normal for a new tank? Will the RO/DI water help? Suggestions?

[metalhead]

Short answer is yes, RO/DI water will help. More than likely you have an over-abundance of nutrients in your tank due to using unfiltered tap water. If you remove all the algae you can and perform several water changes using RO/DI water things should even out eventually. Of course you'll also want to keep all of your other water parameters in check during this process... The water changes should help with this but keep a close eye on your Ca/Mg/Alk levels.

[Parrothead]

Short answer is yes, RO/DI water will help. More than likely you have an over-abundance of nutrients in your tank due to using unfiltered tap water. If you remove all the algae you can and perform several water changes using RO/DI water things should even out eventually. Of course you'll also want to keep all of your other water parameters in check during this process... The water changes should help with this but keep a close eye on your Ca/Mg/Alk levels.

+1 there is alot more goo than just chlorine in tap water, a biggie is phosphates, green hair algae food, get about 75 gallons of ro/di mixed up to match as close as possible temp and pH wise of the display tank and do some 25 gallon water changes about 4 - 5 days apart.