only 1 u-tube will keep siphon on eshopps-pf-1000

so i set up my over flow but only 1 u-tube will maintain the siphon, and some how little air-bubbles are getting into both until the one loses siphon.

im using a magdrive 7 pump

the overflow is rated 900gph and the pump is 700 gph minus head which is a foot to my SCWD then another 2 feet on either side of the SCWD so would be around 460gph or so could that be the problem should i be looking to upgrade my mag drive or would 1 u-tube be ok
or should i have made the SCWD go higher then ran more tubing to the 2 returns

 

My initial thought was along the same lines. Under powered return.

 

i went with the mag 7 cause thats what a few other said to go with but i guess i should have spent the extra 30 to get teh 9.5 that would be at 750 at 3 foot

 

I had a bubble problem until I opened up my return valve more. Flow issue is my guess too.

 

ok so got of the phone with the ppl at DRfostersmith.com (never thought i would have a true person pick up on the get go) i told them the problem and when i ordered it which was 4/22 and they said it would be fine to exchange it.

so im spending $60 more for a mag 12 which at 3 feet has a flow of 880 so i think that should be perfect if not i will go with the mag 9.5 which is 740, i would feel better with the 880 tho and i mean the return is more of 3-4 feet hard to measure truly.

 

Just glad I caught this during the setup stage instead of down the road