My tank has been up and running for roughly 4 weeks, as of yesterday Amonia / Nitrites are at 0 and Nitrates at about 20... I havn't really seen much if any of an algae bloom. I set up my tank initially with tap water but soon after got a RODI unit and have been using an ATO with RODI water since... Is this a problem that I have not had an algae bloom? Also, I havnt been running my lights at all during this time. Is it safe for me to consider the tank cycled and add my first fish on Saturday?