DWC- ecoplus ecoair 8... any1 use this???

k so i picked up an ecoplus ecoair 8 pump... it has 8 airlines... i know the more air in the tub the better but im wondering if it will do 4 18gal tubs fine, 2 outlets per tub??? i figuerd if it wouldnt, i can always "T" a couple lines together... the box says 2.2psi per outlet... it also says 5.2gal per min (312gph)... im presuming thats the whole pump and not 1 line??? if so that breaks down to 39gph per outlet making it 78gph with 2 lines in a tub... so will this do 4 18gal tubs??? any1 else run this pump???
http://www.horticulturesource.com/ecoplus-ecoplus-eco-air-8-8-outlet-p924/

Air movement is all about surface area and water temperature too. Get the water temps down below 70 degrees and you will dramatically increase O2 saturation levels in your H2O. You can pump it up until your blue in the face, but if your nutrients are over 75 degrees it will not even matter how much you huff and puff you will have blown your wad for nothing. You should be fine with these numbers singled or doubled if your nutrient temps are around 65 to 68 degrees, so keep it cool, think about a water chiller as an upgrade at some point. I run a small single line fish tank air pump on a twenty gallon res, but my little single res also has 1/10 hp water chiller and fine mist high quality stone.

Tip: To clean your air stone and keep them working like new soak in weak solution of hydrocloric acid over night. Then rinse with water and h202 pushing air through it on the rinse. Soak after cleaning in pH adjusted water if you really want to ensure no left over pH issues might come about, but you should be fine. That is how you clean an air stone. No need for fancy stone cleaning solutions, but you can do it if you wan to.

I would run two pumps that way if one should fail you still have one pumping just 1/2 the bubbles that you would normally have.

I have a similar model but 4 outlet