How big is the return section of your sump

[dzhuo]

I just bought a 40g breeder to mod it as a sump. How big should the return section be to prevent the return pump to run dry? The return pump I am planning to use will either be a Ehiem 1060 or 1062. The overflow will essentially by the BeanAnimal style (one 1.5" full siphon, one open channel and one emergency). Thx for any help.

[pjf]

My return compartment comprises about two-thirds of my 29-gallon sump.

The return compartment holds about 18 gallons when full. The evaporation rate is about 2 gallons a day. It takes about a week to trip the shutoff sensor for the return pump. I try to perform water changes each weekend. The salt is mixed in the return compartment.

Not pictured is a GFO/GAC reactor that resides in the return compartment.

[dzhuo]

What return pump are you using? and what your overflow capacity?

[pjf]

The return pump is an Iwaki MD-20RXT.

If the sump is full with the water level at the top of the 2nd baffle, then the overflow capacity is about 5 gallons. If the return nozzles are placed high to break siphon, that should be enough. The overflow capacity increases as water evaporates.

[Wippjas]

I would suggest you keep the return section on the smaller side. This way you can use it as your evap. top of section as well. The less volume you have there the less often your top off will run, reducing the effects of large additions of fresh or Kalk water depending on which way you go.

Just my $.02

[dzhuo]

You think my 40g breeder is a bit small for my 150g tank? I am planning to divide the sump into 3 sections. One for skimmer, one for fuge and the last one for my return. Obviously, the skimmer section needs to be large enough for the skimmer and the rest of the space will be used by the fuge and return. A 40g breeder is 36"x18"x17". Assuming the skimmer section takes up 18"x11" then it will leave me with 25"x18". How do you think I should divide the return and fuge for this space?

[dzhuo]

Originally posted by Wippjas
I would suggest you keep the return section on the smaller side.

Yes I was thinking about the same thing but I am worry about the return pump running dry if there isn't enough water volume in the return section. Maybe I should just use 2 sections instead of 3. So one section is for skimmer and the fuge and return is merged into a single one. I will then use some sort of screening to prevent the macro algae from suck in by the return pump.

[woz9683]

I've always kept my return section just as small as possible because it's basically wasted space.

My sump is about 70 gallons at normal operating level and the return section is maybe 3 gallons. I rely on my ATO to keep the return pump from running dry.

[ChuckLawson]

I also lean towards small return sections and ATOs. Basically, anything more than enough room to maneuver the return pump around always seems like a waste to me.

Plus the smaller the return, the greater the fluctuation of water level on evaporation, so the ATO runs in more frequent, smaller bursts, minimizing salinity swings.

[scaryperson27]

I wanted to mess around in Sketchup. Here is what I would do. If you did this all with glass, then you would be able to take the top rim off of the tank safely.



chances are, you will see in between 3-4 gallons loss due to evaporation every day. Maybe less depending on your setup. In this model, you would have 6 gallons roughly in the return compartment. If you raised the baffle on the skimmer section then you would have even more.

I would go with an automated top off device as others have recommended.

[woz9683]

Oh, my return pump is external too, so I didn't even leave enough room for that.

[james3370]

Originally posted by dzhuo
Yes I was thinking about the same thing but I am worry about the return pump running dry if there isn't enough water volume in the return section. Maybe I should just use 2 sections instead of 3. So one section is for skimmer and the fuge and return is merged into a single one. I will then use some sort of screening to prevent the macro algae from suck in by the return pump.

or you could get an ato kit from aquahub & flip the float over for a run-dry protection on the return pump....that way if the level got too low, it'd turn the return pump off till the chamber refilled & caused the float to restore the circuit.

same principle as they use for run-dry on the ato pump, only modified for the tank return pump instead

[NeveSSL]

Or do the same thing James said with a controller.

Brandon

[JNye]

mine return section is 9" to the tall middle baffle, 7" to the last baffle, so a working footprint of 9x18...75 gallon sump. I run an external pump and could have went smaller with the section. I use a Tunze osmolator for top off. Running the pump dry is much less of a concern($100-200) than dumping to much kalk into the tank and killing my animals...thousands. Plus I look at my tank daily, and even in the winter it would take 3-4 days before it ran dry.

[dzhuo]

Thx everyone. I will go with an ato and make the return section small. So for a 25"x18" section, I am planning to reserve 20"x18" for the fuge and 5"x18" for the return section, does that sound about right?

What are the typical reasons the pump will run dry? The drain and the return GPH don't match? No ato and forge to manually top off? Overflow block for something reducing the drain capacity?

[burnah]

too small

have to refill often, it holds about 2.5 gallons and i get about one gallon of evaporation a week :/

[pjf]

The most common reason for your pump to run dry is evaporation. With an evaporation rate of at least 2 gallons a day, I have to replace evaporated water frequently. An ATO or pump shut-off sensor is essential.

There are other problems that can cause a pump to run dry but they are usually encountered immediately when restarting a pump after a water change. You have cited most of them.

A large return compartment helps to prevent a dry pump. To prevent the pump from running dry after a water change, I make sure that my return compartment is larger than my overflow. Typically, the overflow is drained during a water change. The overflow must be filled before restarting your pump otherwise a smaller return compartment may be pumped dry.

I also like large return compartments for mixing salt solution and for placing equipment such as GAC/GFO reactors.

[sjm817]

ATO, and smallish return compartment is the best setup and is what most people use. If you manually topoff, make sure the return section is big enough to hold enough capacity for a day.

Dont make it overly small though, especially if you use an internal return pump.

[dzhuo]

So if I make my return section 5"x18"x9", it holds only about 3.5g. I do plan to have an ATO but if even with that, would it be too small?

[JNye]

you'll be fine if you do equipment checks every 24 hours, which most of us do I would think. ATO failure or empty top off reserve would be the most likely cause of a problem. When I leave town my tank still gets checked every 48 hours and I have a few reefers on standby in case of a reef emergency.

[dzhuo]

I will try to increase the section a bit but my plan is to leave the majority of the area for a fuge. Btw, what would be the ideal distance between each baffle for the bubble trap?