Need some serious help with a sump

sternicus · Apr 4, 2017

I'm trying to build a sump for my 90 gallons corner flo that I'm building this summer. I'm confused on what I need for return pumps and baffles and all of that. I'm planning on running a reef octopus classic 150 and that's all I know for the sump. I would like to get a trigger systems emerald 30 gallon for my sump but I'm confused on what return pumps I need and overall how corner flo systems work. Any help would be appreciated and if someone would share their cell phone info in a pm if that's easier it would be very appreciated!!

Greybeard · Apr 4, 2017

Sumps are, if nothing else, flexible. What you want in a sump really depends on what you want _from_ a sump.

At it's simplest, a sump is merely a place to put equipment that you don't want in the display. It also increases the total water volume, may give you a place to grow macro algae, or additional bio filter media, etc.

Flow rate: As with most subjects, there are various schools of thought on this, but many folks, myself included, figure 3-5x tank volume is about right. Personally, I like to stay around the top of that range. Figure, for your 90g tank, you're going to want to push 250 to 450 gph. Note, that's actual flow, not pump rating... you loose quite a bit in head pressure. For instance, an Eheim 1260 has a max flow of 640gph, but add in 3' of head pressure and a few elbows, you're probably under 500gph.

Baffles: The reasons for having baffles are to give you areas with a specific water height, break up the sump into different sections, and perhaps help get rid of micro bubbles from a skimmer. Might help quiet the system, as well. Take that Reef Octopus skimmer you're wanting... It will have a specific range of water depths it wants to operate in. That'd be an important spec in your sump, a space, big enough for that skimmer, with the right water depth.

Marineland's Corner Flo system works fine... in my opinion, they can be a bit loud, but they work. I've got a stock corner flo that I've modified to use a herbie style drain with an external return. Works very well for me.

Trigger makes a good sump, it'd be hard to go wrong there... Did you have specific questions?

sternicus · Apr 4, 2017

I really appreciate your response! Nothing in particular that I couldn't find other than about return pumps and how to match the gph with the flow rate of the water through the overflow. I can't wrap my head around it for the 90g I'm planning

smh254 · Apr 4, 2017

You should get a controllable pump so you can mess a round with it to get the flow you want. I have a Jebao dcp-5000 which is rated up to 1400gph. I keep it set at 75% on my 65g with 26" trigger sump. Nice sumps.

Greybeard · Apr 4, 2017

Hm. I suspect I may have deduced your problem. You can't 'match' flow rates. Don't need to, or want to. Flow rate is dictated by the return pump.

Here, this may help: Think of a standard tank/overflow/sump system as a series of 'full' containers. The tank is 'full'. The level of the tank is set by the physical height of the overflow weir. Any additional water put into the tank doesn't raise the water level, it just flows over the weir, and into the overflow box. The overflow box is 'full'. Any additional water that enters the overflow box doesn't raise the water level, it just flows over the standpipe (Durso, by default, could be set up otherwise). From there it flows into a 'full' splashdown section of the sump, over a baffle to a 'full' skimmer section, possibly through a 'full' refugeum section, etc.

The only section in the system that is not 'full', and overflowing as needed, by gravity, is the return pump compartment. The only exit from this compartment is the pump. Water pumped out of this section is added to the 'full' tank, which flows into the 'full' overflow, then the 'full' sections of the sump, eventually back to the return pump compartment. You don't need, or want, to regulate flow from 'full' section to 'full' section, as long as there is sufficient flow rate to handle your return pump, it'll always, naturally, stay balanced.

This is why your ATO float valve/switch needs to be located in the return pump compartment. It's the only place in the system where water level will vary.

The other safety issue you should consider, is what happens when the pump is turned off. All of the 'full' compartments are going to drop to the very top level of the outlet, the pipe and tubes are going to drain, etc. That water needs someplace to go, which is why most of us set our 'full' sumps at about half of the physical capacity of the sump. Gives it some room, for when the pump is turned off.