Modded skimmer

[lth03]

I modded about 3 or 4 ASM skimmer to run recirculated with direct feed from drain and boost up the performance of my skimmer quite bit,currently I ran a G1 with sedra 5000 and very happy with it.
I look on the net and see some skimmer have the pump right underneath the chamber like ATI,Tunze... instead of on the side like most skimmer have.What is the benefit of it?Shoot the water straight up will benefit better than from the side for the skimming purpose?
Anyone have any experience with it please sharing with us.
Thanks in advance.

[FishBulb]

In the case of the MSX skimmers, the pump underneath allows for a much smaller footprint. That's the only advantage I can think of.

[lth03]

Those underneath pump is very small rate about 250 to 350 gph,how can they compare to sedra 5000 or aquabee 2000.1 rate 500gph?
I though if you let the fine bubble contact with the water longer it will skim better,shoot up pump will shorten the contact time.
I am a little confuse about that.

[FishBulb]

The only one I really have experience with is the MSX160 because a friend has one so I've gotten to see it. In this case it uses the Sicce pump which is the same as the bubblemasters use. The pump moves little water but a ton of air thanks to a really oversized volute. It moves nearly 15-20 LPM of air on about 15-20 watts I believe. So very little water but lots of air. Both of my sedra 3500s move about 4 LPM of air on about 30 watts. So that is really no comparison. The Sedra 5000 will suck more air than the 3500 but will also use even more watts. And I highly doubt the sedra 5000 will come close to 15 LPM. I thought the aquabee 2000 was about 7 LPM.
In terms of contact time, the MSX has an elbow that comes off of the outflow tube inside the skimmer to direct the air/water mixture sideways. This does cause a bit of restriction and decreases air draw but it's not a big deal. Frankly, I think all popular commercial skimmers are too short and don't really allow for enough contact time. The more I think about it, the better a really tall air driven skimmer sounds to me. Too bad you just can't fit them underneath your stand.

FB