when i get home i will do a barrage of tests on my water... i get water from marine scene. i would asume that is R/O the whole 9 yards.. i have a very cool salinity checker.. it looks like a colidescope.. but it has a display screen to show light refraction i guess... i change water about every 4 weeks or so.. 15% (i know it should be every 2 weeks) I have bad habits in maintaining my tank similar to that of the bad habits many people have w/ their teeth.. when i say minimal flow i mean.. a very small waterfall (1") back into the tank into the corner.. but its not like the tank is stagnant, i can see that when i stur up dirt.. i do not have algea breakouts, but i need to get some margaritas. as i believe i only have 1 left. i always found those tests lack-luster, as I don't have much in the way of supplement, should i discover i have odd values. my lights are about a year old.. they are 4 tubes of ~6" (two white, two blue). they are compact flourescents. all of this lack of the ability to midify my begginer level tank is really making me think that i should get one that doesn't have a pre-made hood.