I want to use MP40's, but...
 

Please refer to the following awesome MSPaint drawing for reference.

The back of my tank is 30" by 18". The overflow in the middle takes up a bunch of room, and the returns on the sides have bulky elbows which basically prevents putting an MP40 anywhere on the top half of the tank.
I orignally wanted to run two MP40's on this, but it looks like the area available consists of a small 8.5" by 9" window in the bottom corners. Is this really feasable, or am I destined for a sandstorm? I'm under the impression it would just make a mess and not provide much useful flow.

Alternatively I could go with some Tunze 6105's, or some good old Koralia's.

I forgot to mention up top, this tank is a 40" long 3 sided tank, so the powerheads are hopefully moving a good chunk of water a fair distance.




http://i48.tinypic.com/i73at2.jpg

I dunno if my post will help as my tank is a half circle. I have two mp40s and an mp10 all on the back glass. All are run at 100% with sugar sand and no sand storms what so ever and I have a sand sifting goby to boot. I'm thinking it's the placement of my rocks. Are you planning on placing the 40's on the sides of your tank or the back glass? Waves are cool but I prefer the random flow in which the Vortechs offer. You might want to research the pros and cons of both of your choices. Thats a whole different subject alone. Have fun with that.

I would honestly go with 3-4 mp 10's. It will give you more options with placement and the mp40's would probably be running at 75% at most.

This looks very similar to Riceboys tank setup with two MP40s on the back wall and center overflow.

On my tank, having the MP10 4 inches from the top frequently causes vortechs of microbubbles on reef crest mode. Also, I'm using Oolite sand which causes sand storms often. Maybe try a heavier aragonite.

Having them at the bottom isn't the end of the world. In fact it can be benefitial. I can't find the paper at the moment but here was a study showing that to oxygenate the water and have a good turn-over powerheads should be placed at the bottom to push low-oxygen water to the surface rather than having the pumps try to push high-oxygen water down. After reading that I actually moved one of my powerheads down to the bottom corner and have it pointing forward and up at the front glass. This got rid of a big dead zone in my tank.

I'm partial to the Vortech's for a number of reasons (though I'm still too poor to buy one), so I'm inclined to think it'd be nice to get those over the others you mentioned. Personally, I'd go the easy route and place them on the sides of the tank but there is also the option to put them on the overflow. Make two waterproof boxes out of thin plastic and put the dry side in there. The magnets in the Vortech will hold both the box and dryside in place without issue. I've seen this done with square-sided juice containers that had the tops cut off them. Worked like a charm. If you were closer I'd make you a completely sealed box with a heat sink so that you could put the dryside anywhere and not have it overheat.

have you considered un-bulking the bulky elbows? Is it possible to replumb the returns to give yourself more room in those areas?

Thanks for the suggestions guys.
I could unbulk the returns, and I may have been a little pessimistic about them as I could probably squeeze 10-11" up from the bottom as is (flexible return lines).
I think my biggest concern was having vortechs so close to the sand, I figured that would just push it all out of the way, but I'm using special reef grade anyways which is a little heavier than oolite.
I should consider the overflow waterproof box also. That could keep more options open.

Are you sure you want the mp40s? I have them and the noise drives me crazy. I've replaced the parts on them a couple times too already. I use Tropic Eden sand and found it to be much better than any CaribSea brand. It is more uniform, clean, white, and I find it heavier by not getting blown around, even on the smaller particles. You'd have to turn down the power on the pump that close to the sand though - maybe not if you used a bigger size, such as ReefFlakes.

I don't hear any noise out of mine. I don't use the pulse mode to create the wave though, which you do hear a little bit of a hum as it does its pulses. Have you made sure your spacer is set according to your glass thickness and you can also move the wetside around a bit if it's a vibration noise.

Either way, I love my Vortechs!

if you use caribsea seaflor you've got zero to worry about.

not ideal for wrasses that like buying themselves though.