How to choose pump size for circulation/wavemaker?

[smlacy]

Hey,

I've had my 30g set up for about 6 weeks now, and am realizing that the 3 powerheads I'm using for in-tank circulation (hooked up through a WaveMaster) might be too strong. (Or, to put it more correctly, they might be stronger than they need to be)

They're Maxi-Jet 600's. I'm sure that anything I put in there would be fine with big currents, but if I can get away with smaller pumps, that would be nice (less power, less noise, less size)

Any thoughts on how to choose the size of circulation pumps in this situation?

Steve

 

[ChrisRD]

I'm not sure I understand the question. Are you saying you think that 3 MJ600s are too much flow for a 30 gallon reef?

As for size of the powerheads, you won't find stuff much smaller than the MJs that will provide strong flow. Mini-Jets and Micro-Jets (both made by the same company that makes the MJs) are the only powerheads I know of that are a little smaller.

As for power consumption - again, I don't think you can do much better than a small MJ. They only use something like 6-7 watts each.

 

[smlacy]

Yeah, they seem a bit strong, and I was just curious as to what criteria people use to choose circulation pumps.

I'm looking for something to give the tank some movement, but not to really make it look too chatic and turbulent (like it is now) I've tried repositioning, but that doesn't really seem to help much.

I've also thought about making a pseudo-spraybar using some vinyl tubing with holes drilled in it, but I'm not sure of the asthetics of that. It might look really ghetto.

Steve

 

[ChrisRD]

Yeah, one of the disadvantages for many powerheads is the high velocity out of the small nozzle. Ideally you want to have lots of flow, but not overbearing velocities. The key to that is the outlet diameter to your pipes/powerheads. Larger outlet diameters = lower velocities.

In a larger tank, the Tunze Stream pumps are a nice alternative (wide flow) to powerheads. For a 30 gallon, Tunze does make some wide-bore, adjustable powerheads that would work, but they're not cheap (you have to buy their controller too).

A spraybar, or splitting/enlarging the outlet with fittings works well to reduce the discharge velocity, but as you mentioned - aesthetically it's not always the nicest thing.

At this point you've probably already tried deflecting the streams off of the glass or rockwork too.

Another option - as mentioned above would be something like the Mini-Jet or Micro-Jet pumps (also made by Aquarium Systems) which have adjustable flow rates. There won't be a significant power consumption difference from the Maxi-Jets, but they are smaller pumps. Not sure about their longevity on a wavemaker.

One thing I don't like about those small pumps is (IIRC) they don't come with a mounting bracket - only suction cups. If you have sandbed I wouldn't trust a powerhead mounted with suction cups - I'd use a zip tie or something similar to secure it for when the cups fail.

HTH

 

[ChrisRD]

Of course there are other circulation options that eliminate powerheads all together - like having a large return pump with multiple outlets, closed-loops, SCWDs, Sea-Swirls, surge devices, etc...

 

[Anonymous]

Can't go wrong with a surge device if you have the space. 3 MJ 600s doesn't seem like too much to me. What are they, 160 gph? I know the 400 is 106 gph. That would only be 480 gph, or 16 X tank volume. Not really overkill. What kind of corals are you keeping?

 

[smlacy]

Yeah, surge devices are nice, but too much noise & hassle for my little 30g, especially since I don't have a sump.

Anyway, yes, the MJ's are 160GPH. I guess what you guys are saying is that maybe its just fine...

Right now the tank is still "settling in" so it doesn't have any corals in it, just snails, hermits, and some macros, and some vastly receeding hair algae.

I plan on having a fairly sparse combo of corals. Eventually, a small SPS, a Blastomussa, a hammer, some "daisy polyps" (not Goni) and filling it out with some buttons and misc shrooms or softies.

I'm going to try to make the main focus of the tank a Rose Bubble Tip and a mated pair of Perc's.

I think the SPSs are the only things that are really going to need the flow, and the others might be somewhat purturbed by it.

Steve