I test my water parameters every 5 days,my tank is SPS and Chalice's.There are 4 things I test for and thats it,so Im wondering if there is something else others test for that maybe I should.My routine is every 5 days I test P04,MAG,CA,and DKH.All the test are done with Salifert test kits except for the p04 which is done with a Hanna Checker.I don't worry about ammonia,nitrites,and nitrates as I can usually tell if algae pops up that it is time to check for those three.I do a 15g WC every 2 weeks on my 50g cube so water quality is as good as it can gets:wink:I also run these 4 test on my mixed water before the WC and also do a TDS check with a digital TDS meter before mixing the RO/DI water with salt:wink:so if there is anything that is being left out that you test for and think I should, or it just makes you feel better about your tank I would love to hear it:bigsmile: