Formula for Sump Size?

[Jon M]

Hey guys. Got a simple question. Is there a specific formula for what size sump you should use for a specific tank?

I'm currently working on a project 125 gallon acrylic tank and I started creating a 10 gallon W/D this weekend and I'm being told I should consider bigger. I know bigger is better for a sump but as long as a sufficient amount of water is filtered (in this case 250GPH) I don't see an issue...

 

[Juxtaroberto]

A ten gallon has a pretty small footprint, and won't hold much media. Contact time is also important in biological filtration. If the water is almost instantly leaving the sump, not much ammonia or nitrites will be consumed by the bacteria in the same amount of time. A bigger sump lets you put more media in horizontally, so that the water touches it for a longer period of time.

If you're worried about paying more for a bigger tank that's just gonna hold media, you can get big plastic rubbermaids at K-mart, Wal-mart, etc.

 

[Zander_The_RBP]

250 gph is nowhere near enough flow for a 125 gallon tank you need to be looking at atleast a 3-5 turnover rate.

A small sump like a 10 gallon really limits you on what you can do with it. Personaly i would hate working on any sump smaller than 20 gallons.

to put in to perspective my 150 gallon has a sump that is 40 gallons with a pump that is pushinng 750 gph (after head restriction)



you'd have very little room for mechanical filtration media in a 10 gallon sump. My sump is 40 gallons and over 25 gallons of that is bio-media.

 

[juneblood3]

Unless you build a tall bio tower for it. a ten wouldnt do much. Id say just wait and look for a used 40 gallon on here and use that. Or like ^^^ said just use a rubbermaid. there have been some nice onces on here.

 

[Jon M]

Understandable. With the design I have I don't see the water instantly leaving the sump. As far as media I'm goin' to be cramming a lot of Seachem Matrix, pot scrubbers. Here's a pretty much basic layout. Changes have been made since this diagram as well. So as far as the formula for sump sizes, does it not exist? That wouldn't surprise me because I when it comes to sumps there are so many factors that comes into play that depends on your individual setup.

 

[juneblood3]

Thats a good design for a bigger sump but with a ten your water levels in the sump would be all thrown off. If its not running im pretty sure it would overflow.

 

[Jon M]

Jeez. Two responses while I was responding...

250 gph is nowhere near enough flow for a 125 gallon tank you need to be looking at atleast a 3-5 turnover rate.

A small sump like a 10 gallon really limits you on what you can do with it. Personaly i would hate working on any sump smaller than 20 gallons.

to put in to perspective my 150 gallon has a sump that is 40 gallons with a pump that is pushinng 750 gph (after head restriction)



you'd have very little room for mechanical filtration media in a 10 gallon sump. My sump is 40 gallons and over 25 gallons of that is bio-media.

Well I could add another pump side and run them side by side giving me about 500gph. Would that be sufficient?

Thats a good design for a bigger sump but with a ten your water levels in the sump would be all thrown off. If its not running im pretty sure it would overflow.

As far as overflowing, with my setup that's not a possibility. I have a custom in tank overflow constructed. Water level in tank below the overflow level. Sump half full. When powered the sump pushes tank water above overflow creating a cycle. With this turned off the water level in tank would stop below the in tank overflow and the sump would be half full. In any case of a freak accident or BOTH my overflow pipes or the sump clogged I also have a built in emergency overflow inside the overflow chamber.

I've already obtained everything for this sump setup. If it's not filtering the water sufficiently I can do one of two things.

a. Construct a bigger sump. With the stand I'm building I'm not going to be able to fit something HUGE underneath.

b. I have no problem with purchasing a decent canister and running that WITH the sump.

 

[Juxtaroberto]

With that design, you've got about 3 gallons of biological media supporting a 125 gallon volume of water, with a turnover of 500gph (meaning a reduced contact time). I'd say add the canister.

 

[gt1009]

I would go with a bigger sump tank. A 10 gallon sump will be like putting an AC50 on it and saying ok I'm done. Get a 29 or a 40 breeder or something and use that instead.

 

[FSM]

When the pump is off, it will siphon water into the sump. Have you accounted for that? We all know how an overflow works, that isn't the problem here.