Ok...here it is. I guess Waaaaay up close in macro, it does have a color - kind of brownish black.
And like I said, I don't measure phosphates, but everything is....
pH: 7.6
Ammonia: 0
Nitrite: 0
Nitrate: Ranges from 0 to not quite 20ppm
I did have it (the 150) way overstocked with babies for a while, but it's back to a decent level now.
The more I think of it..probably is phosphates, huh? I know phosphate pads can help prevent - but what do you do after the fact? Short of getting an algae eater that will be nasty to the fish?
Any advice would be VERY much appreciated!