What size pump do I need?

[TheReefGeek]

I would go with a mag 7, especially with having just a 25g sump.

1. I don't like to max out the drains, asking for trouble
2. Too much flow through the sump can cause microbubble problems

If you haven't got the tank yet, I would get another 1.5" drain line installed for redundancy purposes, in case one drain line plugs. (even a partial blockage will cause trouble if you are pushing the drain close to its max.

Make sure your return section of the sump is small enough that your display tank can accomodate the extra water volume in case your overflows fail, then you wont flood at all. Installing a low-water shut off float switch for your return pump will keep it from burning out if this were to happen, but if you are using a cheap pump then no biggie.

Use durso's or similar to cut down on noise

Install egg-crate or similar over your overflow box to prevent unwanted visitors