[RichE]

I picked up a 90 gallon tank yesterday and it was a s/w tank. the sump was designed to have the return pump in the middle and the fuge in the last section, and it overflows into the first section where all the media is and also into the last section which was a fuge section (the drain tees off into the first section where all the filter media is and then into the last section.

So my question since this is going to be a low tech community tank, I am curious about the return rate I need on this tank.

Its a 90 gallon display with a 40 breeder sump ( i would guess around 115 total gallons.

With that being said what is a good ratio for return on a tank like this?

I know on tanks with bigger bio load's the rule is 8-10x's turn over

Also in the last section of the sump where it was a fuge for s/w i was thinking of adding some crayfish in there to eat anything that gets int here since the drain is going into there along with it going in the first section.

I will have low maintenance plants in the tank but is there any good plants to put in the "fuge area" I will skip the crayfish if needed and put some coreys or some other bottom feeders int here that wont eat plants

Thanks

 

[aja31]

The amount of water that flows through the sump is limited by the hole size of the overflow, and the type of overflow.

For instance, a tank I am currently building has a single 1" drain that will use a durso style drain, which is capable of ~300-500 gph. That is what sets the return pump size.

 

[Bobbybills]

5-6x is fine, so 500-600gph.

 

[Bratmanxj]

Like Aja31 said, details on your overflow will help us better answer your flow question; size & number of bulkheads with location (back or bottom), overflow box size & style. Considering it was a saltwater tank I'd assume there is plenty of headroom available on the flow rate, but rather be safe than sorry.

 

[PhysicsDude55]

Depends on what you're going for...

If you want a heavily planted tank, then don't put any plants in the sump. With the sump, you can essentially have "115 gallons worth of plants" in the 90 gallon tank. Any plants you put in the refugium means that many less plants your main tank can support.

If you're going for a heavy bioload with not a lot of plants then lots of plants in the refugium is the way to go.

4-6x turnover is fine for a planted setup, but if you want more flow you can have more flow.

 

[klibs]

If you want a heavily planted tank, then don't put any plants in the sump. With the sump, you can essentially have "115 gallons worth of plants" in the 90 gallon tank. Any plants you put in the refugium means that many less plants your main tank can support.

This is not necessarily true

More plants will consume more nutrients. If you want to have 'nitrate sponge' type floater plants in the sump (obviously with a light in there too) it does not mean your main tank will suffer unless your nutrients bottom out. Totally depends on the density of plants in your main tank, how much you are dosing, light levels, CO2 levels, rate of plant growth / nutrient consumption, etc... You can make any combination work here. I always say the more plants the better. Makes everything easier. More fast-growing healthy plants in your setup usually mean less algae / overall issues.

Like others said the rate of your return pump will entirely depend on the flow rate that your bulkheads on the tank can handle. I also agree with you that more turnover is better.