I even tried using 3rd pipe by removing 5 inch long pvc pipe. I’m using 1” pipes. When I had 1-1/4 in my previous setup didn’t have this issue. Also my water returns right next to overflow. That can’t be good. So I’m thinking I should either silicone a 3 inch piece of glass next to pipes since that’s where it erupts every 5 seconds or so. I decided not to rinse the old sand and now I’m getting ammonia over 3 my Hannah won’t show more. Also didn’t use RODI water originally but did condition it. Now RODI fixed and filters replaced back to single digits down to 9 now. When I tested it with water tester it was showing 200-300. I was using old filters and discharged water. I was thinking it was better then tap water but after I got water tester I realized I screwed up once again. Waiting on new salt to arrive along with dr Tim’s one and only. Oh my old tank was a few years old. Old one was over 200 gallons this one is 2x2x6 so about 150 plus about 20 in sump. Been cycling about 10 days. Please advise me on flow and how to set up my filter sucks, where to best place skimmer, bubbles Magnus auto paper roller filter and Cato. Eventually wanna dump sand in sump and grow corals on bottom as well. Forgot to say I had a difficult rushed move couldnt make new aquarium in time… started over after about 3 months. Sand was in a plastic container in basement. I was trying to save some bacteria( Thanks for your help