Floating Pond Filter

[readingj]

My "filter" is a 6" ABS pipe with half-inch holes drilled in it, wrapped in window screen. This is all attached to the input of the pump. It is really meant just to keep the fish from getting sucked into the pump (1800 gph). This is a new filter, the old one was a 2" ABS, and would get clogged too easily, so I wanted more surface area so it wouldn't clog.

However... Somehow the filter fills with air to the point where it floats to the top of the pond and the pump, although still 2' under water, is just sucking air. I have weighted the filter with a brick, but it still floats up. If the filter is completely under water, how does it fill with air in the first place? Any ideas?

The pump goes into a 1 1/2" line up to the water fall, and when the filter fills with air it pivots on that pipe so that the filter is able to rise out of the water. As soon as I unplug the pump the air leaks out and the filter pivots back down to the bottom of the pond. It has been running about 6 hours today without floating to the top, so I unplugged the pump to see if any air bubbled out of the filter (the water is extremely cloudy, so I cannot see the filter nor pump directly). I got no bubbles, which suggests to me there was no air in the filter, so apparently it is not filling a little at a time.

I repeat the question, any ideas on how air might be getting into the filter?

Thanks,

John

 

[Mmathis]

I’m having a hard time picturing the filter. If you could post a few pics, it would be very helpful.

 

[JRS]

I have had the same issue with different small foam pre filters and also filter boxes with the pump in them. More weight solves the problem for me, not sure why it happens, assumed it was microbubbles getting trapped and accumulating.