Noisy Overflow

I just received a new pump to transfer from sump to tank (500gal. hr) I have a overflow box with a 1" return to sump, with this new pump the noise from overflow is tremendous

So the water is coming *out* of the overflow via 1" pipe?

It sounds like the pipe isn't large enough and you're getting air trapped in the pipe which is inhibiting the increased flow. Couple of things to try

Increase the pipe size or

Correct the position of the pipe and add a breather tube.

The breather tube would be placed inline and would then go upward above the water line.

This breather/vent will allow water to flow better. See http://www.simplifiedreefkeeping.com/sumpdiag.gif

Although the diagram is for a larger pipe the principal is the same. Although you'll probably find the vent to be a bit noisy as well.

I would check the way the 1" pipe is setup and redo it so its either close to vertical or if its angled to have the angle in as straight of a line as possible.

You can see a *muffler* for one of these vents in my book pg 191

I have a prefilter sponge in overflow, but doesn't help. I have tried everything, nothing works except to restrict flow which inturn defeats purpose of new/larger pump.

I know I read in your book about suppressing the noise, but for the life of me I can't find it in the book again, any suggestions? I tried a standpipe and reducing returnline to no avail. I would hate to spend the $ on larger pump if I have to reduce back to the flow of old pump. As far as the overflow I tamed the noise quite a bit by suspending 2 standard size airline tubings into drain line from overflow, each about 15" long, 10-12" into drainline and the rest hanging out the box, now all you hear is the water without all the air gulping I had before.

(same principal as your breather tube) The water falling I can handle, the air gulping was just way to noisy. as it pumps now I am getting 445gals.hr @ a7-8'head./