have a pump problem

[cartoonbear]

right now I am having trouble with my current pump. It is external and is pumping bubbles into the tank like crazy. It is nothing in the sump and it is def. coming from the pump. Everything with the plumbing is fine, so I've decided to change to an internal pump.

Do you think this will fix the problem?

The tank is a 125, what pump should I use? What gph? What tubing to return?

Thanks :)

[sjj80]

I've only used submersible pumps and have had no probs w/ bubbles coming from the return, if you do go this route make sure that you rotate the pump a few times underwater before attaching it to rid of all trapped air. But surely there's gotta be a way to fix your external pump so that you don't have to buy another one unecissarily, Sorry I can't help with this. Hopefully someone else can.

Good Luck

[michaeldaly]

The only way a pump can be pumping bubble is if air is leaking into it.

Either it is sucking air in from the sump or their is a small leak in your plumbing.

[AZDesertRat]

That's not entirely accurate. It can have a starved suction which would cause cavitation inside the pump volute leading to bubbles. The sump could be 100% bubble free but if you restrict the pumps intake in any way, that can be a sponge filter, small fittings, long pipe run, valves, vertical lift, up and over type arrangement or any number of things, it can cause cavitation.
Always plumb the suction with as large of pipe as feasible, short straight distances, no vertical runs such as over the side of a sump and with as few fittings as possible for best results. Centrifugal pumps are designed to have positive suction head, or a flooded suction with water higher than the pumps centerline.