By Request - green tank pics

[DJ88]

Alan,

I have probably missed this somewhere in all the posts but what about your top off water? is it RO/DI? What may have happened is that you have slowly built up enough "stuff" from your water that it is feeding itself now.

Personally I'd suggest getting all livestock out in another tank and do a 100% water change with RO/DI.. wait a week or two. and do another. only with RO/DI.

I know how it has been said how clean the water is there but I am sorry. Tap water is not THAT clean. I don't want to sound condescending but you will get impurities that will vary from week to week in a city water system. It's a fact.

By the looks of it your tank has bult up the nutrients that it needed in cunjunction with your feeding of DT's to become a self sufficient DT grow out tank.

Your only recourse is get it all out.. basically "wash" the tank.