powerheads...

[thedirtboys]

I just got a 24g nano cube. It has a Rio 1100 for the return pump but I'm going to get another powerhead to help move stuff around. How many GPH should I be looking at?

Thanks

 

[Whys]

Recommendations for total flow are 20x display tank volume or higher. That would put you pretty close to 500gph total, so subtract the Rio gph to find the right powerhead.

 

[der_wille_zur_macht]

What are you going to be keeping in the tank?

 

[Chago09]

yes 20x is the recomended, personally I never had success with only 20x. I seemed to always get dead spots or slow areas which would then turn into huge detritus build up or algae prone areas. My tank is at 28x now and I'm still not satisfied. Try to aim for atleast 25x. Don't be afraid though of to much flow, people on here have above 40x.

 

[der_wille_zur_macht]

<a href=showthread.php?s=&postid=14791613#post14791613 target=_blank>Originally posted</a> by Chago09
Don't be afraid though of to much flow, people on here have above 40x.

There are plenty of people who have more like 100 x tank volume.

As with many other rules of thumb, I'm not a big fan of recommending flow based on tank volume turnover. Livestock requirements aside, there are a TON of variables:

1) Live rock configuration. A tank with more live rock/less open space will require more energy to keep the water moving.

2) Type of flow. Do you have powerful jets blasting out into open space, or a more gentle spread of water movement?

3) Distribution of flow. Are there dead spots in your tank? Using tank volume turnover rules of thumb basically gets you at a certain average flow, but tells nothing about distribution of that flow.

That said, the first goal is to not have dead spots where detritus can build up, or nuisance algae can gain a foothold. The second goal is to meet the needs of your corals or other sessile inhabitants. You can be off in both directions here- many species thrive in lower flows, wheras others (think: small polyp corals) really need a pretty high velocity.

 

[thedirtboys]

Thanks for the advice. I'm looking to keep a little of everything in it. My tank has the 28g metal halide system from nanotuners so lighting won't be an issue. I've been looking at the Hydor Koralia pumps. Any opinion on those?

 

[Whys]

Many will tell you Koralia are not good quality. Many of these same people have one and use it. I am one of these people.

I use a Koralia 1 for circulation in my mixing buckets. It's gph is about half what it says on the box. I don't know if the same is true of the other Koralias, but they are popular either way.

 

[Chago09]

<a href=showthread.php?s=&postid=14795594#post14795594 target=_blank>Originally posted</a> by Whys
Many will tell you Koralia are not good quality. Many of these same people have one and use it. I am one of these people.

I use a Koralia 1 for circulation in my mixing buckets. It's gph is about half what it says on the box. I don't know if the same is true of the other Koralias, but they are popular either way.

wow I love by koralias and swear by them. Like der_wille said, there is a lot of variables to look at like dead spots etc. Thats basically what I did. I fiddled with adding more powerheads and changing their path until I was happy. I don't really care what the gph rating is on the box

 

[der_wille_zur_macht]

<a href=showthread.php?s=&postid=14795594#post14795594 target=_blank>Originally posted</a> by Whys
It's gph is about half what it says on the box.

The advantage of a Koralia or similar powerhead (i.e. a prop-style powerhead) is that the flow it produces is diffused over a large area, as opposed to a narrow jet of water as produced by a traditional centrifugal powerhead. Since the flow is so spread out, it typically feels much weaker than it actually is. This is a good thing, though.