Why is Nitrate different in tanks????

some places sell cleaner clams that are supposed to help reduce nitrates as they feed. i have a freind that has them in his refugium that has a regular light on the top.
 
A refugium sounds great! I don't really want to put macroalgae in my 60 gallon. I have a tough time pulling it out of the nano tank because it grows so fast. A refugium would be just the thing to experiment with to see if the algae and sand would help reduce the nitrates. Thanks everyone! I appreciate all the responses.
 
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