kcarmartinez

I am now almost positive the holes are to adjust to your aquarium size. But what goes in them I am not sure. It does have a turn nob to adjust the flow, and it did come with a lid (just didn't show it because then you couldn't see the sections). Aquaclear sounds like a pretty good answer. I think it may be missing one section insert, but I may just do my own inserts anyway.

Toddnbecka

Aquaclears have an adjustable leveling device on the bottom of the case. I suspect someone made the holes for some reason after they got the filter.

kcarmartinez

Very Sadly I must report I think I may have killed Mr. Filter. He was happily running with a VERY used cartridge from my 75G Malawi tank to get the cycle going... But we had an issue with the electric line it was on and it took us a day to figure out it was just a tripped GFCI on another outlet. We hit the reset button and Yeah, it was on again. That was Yesterday. Today I went down and noticed it was on but no water was coming out and it was mostly drained. I hear it, but it is not strong enough to pull the water up the intake. I tried filling it up with water, but I think we may have burned the motor out running it dry. :-(

Fish Guy

I have a filter that has the a similar design.

Wowzergsd

Hi - looks identical to one i had about 20 years ago! that was made / marketed by (in the UK anyway) by Interpet. I think the 4 holes might be for a peg, to adjust for different thicknesses of tank glass.