Sump size?

[Mike7744]

I just bought a new 125 gal tank. What size sump do I need for this size aquarium?

 

[Fish Fan]

Congrats on the new tank. I think this is one of those, there's no right answer here. I'm sure someone has a 125 with a 10 gallon sump, and someone else is running a 125 with a 125 sump lol!

But I think a 40 breeder would be a good place to start. Maybe a 60 breeder if you want some more sump room.

The Aqueon tanks are on sale at PetCo currently, and if you're looking for a sump baffle kit I think these are the best value hands down:
https://www.ebay.com/str/marinebiosystems?_trksid=p4429486.m3561.l170197
Good luck!

 

[slingfox]

For reference, the RedSea 525 is a 110gallon display with a 30 gallon sump. You primarily need a sump that is large enough to fit all the equipment you plan to use. I don’t run a lighted refugium anymore and the 30 gallon has more than enough room to fit a Reefmat 1500, fairly large protein skimmer, small extra protein skimmer I use for ozone, two return pumps, and a small/medium size chamber which houses a bunch of biomedia / cryptic refugium (used to be a lighted refugium).

 

[mboley]

As large as possible for your stand. There is no downside to more water volume.

 

[PotatoPig]

My 2c:

60 breeder

A 40 breeder would probably fit all the equipment, but the extra area from a 60B will give you much better ability to accommodate back-siphon while still being a lot shorter than the DT so should be easy to accommodate under the stand.

The Breeder tanks are also a nice option because they’re a bit shallower, so access into the tank for maintenance is easier with limited clearance available under most stands.

 

[Mike7744]

I have a 20 gallon sump. Could I use that on this tank? Without a problem

 

[Fish Fan]

I have a 20 gallon sump. Could I use that on this tank? Without a problem

You could, but I expect tht you'd want more room for equipment than a 20 gallon would hold.

 

[Mike7744]

You could, but I expect tht you'd want more room for equipment than a 20 gallon would hold.

I would have to use it temporarily until I buy a 40 breeder.

 

[Fish Fan]

I would have to use it temporarily until I buy a 40 breeder.

That's fine. If you're looking, PetCo has the 40B 50% off currently.

 

[Mike7744]

That's fine. If you're looking, PetCo has the 40B 50% off currently.

Yeah, I know, I just bought my 125 gallon there at Petco. It was half off.

 

[Science/G]

30 - 40 gallons

 

[PotatoPig]

I have a 20 gallon sump. Could I use that on this tank? Without a problem

I’d strongly recommend against it.

The 125 has a much larger area than the 20 so even a nominal back siphon from the Display Tank when you turn off the pump will cause a large rise in water level in the sump.

A quick calculation, assuming. A 20Long sump, for every inch siphoned out of the 125 you’ll get 3.6” of water rise in the sump. Then you also have the elevated water level in the DT while the pump is running - probably about 1/2” ish before flow into the drain equalizes, that will drain into the sump.

Even with the return nozzle barely below the surface you’re risking a flood if you have more than about 6” of water depth in the sump, and at that point your return pump is going to start to have issues sucking in air.

 

[Mike7744]

I’d strongly recommend against it.

The 125 has a much larger area than the 20 so even a nominal back siphon from the Display Tank when you turn off the pump will cause a large rise in water level in the sump.

A quick calculation, assuming. A 20Long sump, for every inch siphoned out of the 125 you’ll get 3.6” of water rise in the sump. Then you also have the elevated water level in the DT while the pump is running - probably about 1/2” ish before flow into the drain equalizes, that will drain into the sump.

Even with the return nozzle barely below the surface you’re risking a flood if you have more than about 6” of water depth in the sump, and at that point your return pump is going to start to have issues sucking in air.

Okay.
Good to know, thanks.

 

[Fish Fan]

I think most would vote for the 40 breeder here (60B a close second). It fits your stand AND allows room under the stand for other gear, like ATO res, dosing res, electronics panel, etc. It should hold all your "wet" equipment, and if designed correctly should easily accommodate the backflow if/when the power is turned off to the system.

 

[mjszos]

Ultimately there's a few considerations for a sump, but no hard and fast rules behind it:

• Make sure it has the capacity to store your desired filtration equipment.
• Make sure it has the capacity to store the siphoned water from your display without overflowing

For context, I have a 100G DT with a 50G sump. It's massively oversized, but more water volume is almost always a better thing.

 

[Fish Fan]

Around 2009 ish, I had a 125 with a DIY 55 gallon sump, worked great. I still have the sump, if anyone wants it, please let me know lol!

Currently, I'm looking to build a 150 gallon 60"x24"x24" and I'm deciding between a 40B and a 60B. I absolutely want the 60 if I can figure out how to fit everything I need under the stand.