I set up my 30 gallon cube yesterday and need to know how many GPH I want in an aquarium that small. I will likely use 2 though only have one on at a time to simulate tide changes.

bump

i think for a reef tank you want a power head that is something like 4x(# of gallons in the tank). So you would want something along the lines of 120gph at the minimum per powerhead. Best PWHs to get would be ones you can aim or that have rotating nozels.

I'm no expert just what i've read. I know I saw somewhere there was a breakdown of what powerheads should be used for the various tanks.

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100G->African Cichlids:Kribensis-2,Bumblebee-2,Red Zebra-2,Elec. Yel. Labi.-2, Acei-2, Elec. Blu. Johanni-2,Peacocks-2 / Community: Australian Rainbow-3,Turquoise Rainbow-4,Dalmatian Mollies-2,white molly-1,Dojo Loaches-1/Cleaners:Chinese Algea Eaters-5/Murderers: Dinosaur Bichir-1And lots of other tanks,2-Gourims,6-Rams,1-Arrowanna,6-FW Flounder,1-Farlowella CF, 1-Spiney Eel

Hmm that doesn't seem very strong. I am using a 140 gph in my 10 gallon right now and even that seems a little tame. My clowns get right in front of the stream and swim against it once in a while. Looks fun lol... I do have another equal powerhead. They're penguine 550's maybe I'll just use both of those. You can turn them etc.

You're right it should be more powerful, I just found one of the site that gives a good breakdown on the GPH for fresh and saltwater tanks.

Aquarium Circulation

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100G->African Cichlids:Kribensis-2,Bumblebee-2,Red Zebra-2,Elec. Yel. Labi.-2, Acei-2, Elec. Blu. Johanni-2,Peacocks-2 / Community: Australian Rainbow-3,Turquoise Rainbow-4,Dalmatian Mollies-2,white molly-1,Dojo Loaches-1/Cleaners:Chinese Algea Eaters-5/Murderers: Dinosaur Bichir-1And lots of other tanks,2-Gourims,6-Rams,1-Arrowanna,6-FW Flounder,1-Farlowella CF, 1-Spiney Eel

Hydor Koralia Evolutions would be a good choice. Thye have a nice wide dispersed flow pattern so move lots of water but in such a way it is not like a jet stream.
I keep my reef tanks with between 30 and 40x turnover using multiple powerheads.

wow nice I looked up those Hydor Koralia Evolutions. They sound great and they don't even cost a lot. I paid the same for my last 135gph ph... annoying but I'm grateful for the suggestion. Ordering it now.

you need at least 20x for a reef. The koralia do work well. i have two on my 20 gallon.

The Evolutions are also controllable meaning a timer or a Reefkeeper Lite controller can turn them on and off for wave action or random flows. Most powerheads fail if started and stopped frequently. I have been running two Evolutions 1400's for over a year now on my RKL controller switch on and off every 30 seconds and they are still dead silent and working great.

hmm well I was about to order one that does 750, should I go with 2 lesser ones? 20x30 = 600

two lesser ones will give you a better random flow..

agreed

Well I ended up getting one since it was cheaper. I turned it on and my clowns are swimming hard now. They have places to rest but I am wondering if its too much now. I ordered it online so I may end up plugging up some of the ribs so not so much water jets through since I can't just drive to a shop and return it. Would it even help? It's doing 750gph and its a 30 gallon cube

That miiiight be too much flow directed at them all at once. a few things to try would be to point it at the surface from the bottom back left to center front, at the back of the live rock, from the back center towards a side wall or from the front to the back on a side. It'll take a bit of positioning to get everything right so just move it and point it around until you find something that looks like it works for your tank.

one other thing to try is to get a piece of plastic in a triangular shape and put it on the front of the powerhead to direct flow into two places instead of one. Not exactly sure how you can do it but possibly three equally shaped rectangular pieces of plastic super glued together using aquarium safe glue and hooked to the powerhead.

For example, i have a 550 and 425 gph that i tried from the bottom and sides and a few other places. Finally found that if i used them high in the tank, pointed them up, forward and toward center which gave a good flow over all the coral, high flow for those corals that needed it and good high flow/low flow spots around the tank for the fish to both swim quickly and rest.

One thing for your fish though, its good to have some spots for them to hide in and rest during the night. So be sure to have some caves or overhangs.

Good luck!

I ended up buying a maxijet 400. This has a circulation pump mod in box that does 500gph. I hooked it up and the thing is crazy loud... The impeller spindle is longer then the parts and there's a good quarter inch maybe a wee bit less but a good amount of space for the parts to slide around, hence all the racket. I should have just stuck with my two tiny powerheads...

You can do just the 400gph setup with it and get a smaller powerhead to put in there somwhere else... possibly?

yeah but if that noise doesn't stop I may take this back too. I can hear it 2 rooms away with the door shut. I might try to crazy glue the impeller parts

I'd take it back before you try messing with it with glue. Probably be best anyhow if its that freakin loud! wow! the ones i have dont make any noise from what i can tell.

Possible it has air trapped in it, I know mine will make noise if I don't move it around some in the tank to remove the trapped air.

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100G->African Cichlids:Kribensis-2,Bumblebee-2,Red Zebra-2,Elec. Yel. Labi.-2, Acei-2, Elec. Blu. Johanni-2,Peacocks-2 / Community: Australian Rainbow-3,Turquoise Rainbow-4,Dalmatian Mollies-2,white molly-1,Dojo Loaches-1/Cleaners:Chinese Algea Eaters-5/Murderers: Dinosaur Bichir-1And lots of other tanks,2-Gourims,6-Rams,1-Arrowanna,6-FW Flounder,1-Farlowella CF, 1-Spiney Eel

Well the shop was closed yesterday so I tried the glue. The glue worked like a charm! It dried in a few seconds and the noise is gone.