Mag 18?

[Devaji108]

Hello everyone
one of my return pumps is not pushing the amont of h20 as it should and the over flow is not working right.
it's a mag 18 with only 4 feet of head and the h2o barrly makes it out the return??
it is on a 240 gal 96 x 24 x 24 with anthor external blue line pump rated for 1105 GPH and that side of the tank is working great.
there is big air bubles in the return line from the mag. 18 like 3-5 inch air bubles??
what wrong here?
Deva

 

[bmwardo]

How many overflows/drains do you have? Is your tank Reef Ready? If each pump is "fed" by a separate overflow one drain might be higher than the other or your tank might not be level causing one to take in more air. Do you have durso standpipes? If you have dursos you may want to make sure the air hole in the top is not clogged up with salt.

If your pumps are coming from a sump then you have to figure out where bubbles are getting sucked into the mag.

 

[roguemonk]

If the pump is pulling air because it's sump is low you won't get nearly as much flow out of it. I don't know about a Mag 18 off the top of my head but I'd worry that it might burn out if it runs dry. I think Brandon hit on the most likely scenario based on the information we have so far.

If you're plumbing from two separate overflows I would put them into the same sump because otherwise you're always at risk of an imbalance that can quickly become catastrophic.

Brad