[Lsufan]

From the sounds of it I take it u have a bottom drilled tank. If that is the case then I would go ahead & attach the airline like Nano suggested. To me on a bottom drilled tank u would have to set the open channel standpipe so low that u would have a waterfall entering the overflow box makeing noise. The airline is meant to be just above the emergency & I would set it up this way. It works better with the hieghts & water levels on bottom drilled tanks. On back drilled tanks with interior overflow boxes it can cause startup issues having the hole or airline below the emergency. The only time I might try not to use the airline on the open channel standpipe is on a ghost type overflow box. That is the only type of box that I don’t see a way to have a issue with the hole or airline being below the emergency.

If u just don’t want to use the airline then I suggest placing the standpipe as high as possible to where the hole is actually just above or even with the top of the overflow box. It may work that way & not cause any noise. There are other deciding factors to know for sure if it will work or u will have issues. U could always add the airline later if u do have a issue. It shouldn’t be anything that would cause a flood