I am concerned about the intank sump in my aio. I have 3 chambers. The first chamber where the tank water comes in the back chamber has stagnant water. I even see a little film forming. I had to turn the return pump down because I keep getting microbubbles. Im not sure if me slowing down the return pump is causing this issue but I would like advice. I have a pre-seeded filter, another sponge filter, satchel of purigen and a carbon satchel in the first chamber. The 2nd chamber i have a satchel of bio balls, a small piece of pre-seeded filter and more carbon. In the third chamber I just have the return pump. The water gets terribly low in the return pump chamber if i turn the pump on higher and creates microbubbles. I top off the water in the tank often but I'm not sure if my water level is too low or if I have too many sponges in the chambers. Any advice please