As Logen32 said, it is usually a long process involving several factors. The causes of this stuff are primarily, low flow, overfeeding, lights out of spectrum, high phosphates etc... In other words there can be a lot of causes. The tap water you used may have been loaded with high phosphates. Water changes along with sucking out as much of the stuff as you can, should get you back on track, if that was the cause. In my case it was caused by several different factors, but I just about have it beaten now. Everyone says the red slime remover works great. I ordered some online, but it was back ordered and I haven't received it yet. I think the problem will be solved before it gets here. If the slime comes back though, I'm going to try the remover. Good luck with yours! :happyfish