Algea and snails

Question
Our 29 gal tank has been running for 5 weeks and we currently have 4 hermit crabs (thanks for the advice on them) cleaning the substrate and we added a clown fish a couple weeks ago and now we're seeing green algae, furry looking stuff.I read about getting margarita snails, somewhere I read that with a tank my size I should need about 40 cleaners -- is that true??  That seems like a lot.  Thanks in advance for your help.  Merry Christmas!!

Answer
Hi Terry. Merry Christmas to you too! Margarita snails are a bad idea. They come from rocky intertidal areas of the northern pacific coast in north America. While they can withstand short periods of warm water in the summer in nature, they will only survive a few weeks or maybe months in a tropical marine tank. When snails die in a tank they can pollute it pretty bad and this pollution will only add to the algae problem in the long run. The problem you may be having is one with your phosphate and nitrate. These two levels will feed an algae growth. The hair algae will utilize much of these for its growth so when you test your water for nitrate and phosphate you may be getting low levels but that is only because the algae is taking them up. Try cutting back on feeding a little and doing more frequent partial water changes. To help control this algae you may also want to get some turbo snails or nerite snails. These will do a much better job and will live indefinitely in a warm tank. You do not want forty of them for your size tank. Start off with a few of each to ensure there is enough algae to support them. If they do not seem to be keeping the algae in check then add a few more at a time until they do the job. Some other good algae grazers are your sea hares, urchins(long spine and short spine, stay away from pencil urchins), conchs(although some of these get rather large),emerald crabs( primarily herbivores but there have been a few reports of one eating small polyps)and quite a few fish(foxface, dwarf angels, tangs and algae blennies.