Hi All, After having very little success with carbon dosing, I decided to give scrubbers a go. I haven't really followed any guides, only looked at a few pictures and picked up the general gist of what was required. For this reason i'm interested to hear feedback from all you professionals on my implementation. I used 20mm PVC pipe for the entire build, and roughed up all joins before using PVC cement on them. I decided to build my ATS as a loop, so it could free-stand in my sump. The pump sits at the bottom of the loop in the centre and pumps water up both sides of the loop up to the slot I cut in the top using a Dremel. This seems to be giving me quite an even and high flow rate down my screen. The whole system is 55cm high, 35cm wide and has a screen which is 30cm wide and 35cm high. For lighting I just searched eBay for grow lights, and came across these '40w' units in weatherproof spotlight casings. I doubt they are anything like 40w, so I purchased 2 just to be sure and run them 18hrs a day.