Hello! Wow, am I excited to be here and actually running an ATS! I have a 20 gal tank with a 10 gal sump currently. I'm running it as an experiment with an ATS and as a proving ground for how I will set up my larger tank later this summer. I have two juvenile Northern Diamondback Terrapins that are rapidly growing and will need a bigger tank soon. Since Terrapins are brackish turtles, I keep the water between 1.016 and 1.020 specific gravity. I allow this to fluctuate with the evaporation in the sump to better mimic the estuarine environment they come from. The turtles also have some fish for company as well as some inverts for clean up. The new tank this summer will be a 160 gal 3' x 4' tank with 20" water depth with a large sump, and I want to get this all right before I make the investment in the tank in time and materials. So... I'm into week 3 with the scrubber. After about a week I had a quick bit of brown algae then almost immediately started growing nice emerald green hair algae. I made my first screen scrape of the mesh and rinse in the sink on week 2. During the 1st week I still ran my regular in-tank filter (just simple mesh with some activated carbon). Then I turned that off and pulled the carbon out as the green algae started growing. Since then the water has been getting more and more cloudy each day. I know the ATS should produce DOC. I just seem to have an awful lot. My water has gone from pretty clear to very yellow. My sump has now has some algae now clinging to the walls, though there seems to be none in the display tank. Will this greenish yellow water clear up as the hair algae starts growing faster? Is the system just a little too new? Should I start running the activated carbon again? If I understand correctly, the carbon will pull out a lot of DOC. If I also understand correctly, those DOC are beneficial to the tank and to the algae. Thanks in advance for your thoughts and advice!