creating good circulation?

[blaze422]

I am trying to figure correct placement of power heads for optimum circulation for a 120 gallon tank. I have 3 power heads, and was thinking of placing one on each side facing each other , and one in the back middle. Is there a strategy? How high up the tank should I place them? thanks,

[Maxxumless]

My strategy is to accomplish three things; 1. No dead spots, 2. Keep things in water column as long as possible, and 3. Plenty of surface agitation. It is often much better to go with 3-4 smaller PHs than 1-2 larger ones. The key is volume not velocity.

You can always just face them toward each other in some manner, but LR makes every tank different.

[fishermike]

It really depends on the needs of your tank's inhabitants. Research is showing that many sps require high velocity to really flourish. I think that turn over is important but equally important is velocity. It is easy to create turnover but if you fail to address velocity your tank will not live up to it's potential.
Try placing two of your ph's on the back wall at opposite sides of the tank. Alter the height and point them towards the center of the front glass. Take the last ph and place it on the back wall mid tank pointing at the front glass. The three streams will converge and create a good turbulent flow of water.

[blaze422]

thanks, but please address height off the bottom....(27" deep tank)

[Maxxumless]

What are the PHs rated at?

[blaze422]

I was afraid some-one would ask...I'm on the way to my office and will get back to you on that...

[blaze422]

in line pump is 6.4 GPM....power heads don't say....

[Maxxumless]

Hummm, a pump you say? So, are you going to use the pump for a sump? Well, I would dump the pump but surly use a sump…. Grrr, damn you Dr. Seuss.

Seriously though, that pump is not strong enough for most sump designs and you would have to do some plumbing to use it well anyway. As for the PHs if they have a brand and a number on them then it will be pretty easy find out what they are. And you say its 27 inches deep? Is this a custom tank? Or could it be 24�?

You might want to back up just a tad and give use some numbers like tank dimensions. Getting good water flow is more often than not a trial and error endeavor that changes as you purchase corals (who particularly are affected by water movement). Two or three PHs/pumps could create good flow depending on there rating, placement, nozzles and the rock work; however, if this is going to be a fish only or fish only with live rock tank then it becomes less critical as how they are placed. Personally, for your size tank I would not have less than four water flow inlets whether they be from PHs, pumps or from returns (from sump, filters, etc…). The key is to keep from having dead spots in your tank – places where detritus builds up. And you really do not want this to happen in areas where you cannot siphon or blow it away with something like a turkey baster.

[blaze422]

ouch...this is getting too complicated! I bought a couple of cheap ( $22) powerheads, and a submersible pump and thought I would have a "cool" propeller on the submersible and position the two PH's on either end and ipso, facto, I would have circulating current.... I also read about one reefer who put a perforated PVC tube in the back and had connect to the sump return... My tank is 60X18X27...has a wet dry trickle with a sump...in the sump is a protein skimmer..