Quick Sump

[WolfieCA]

I have a 42 X 13 X 15 which I am using for a sump. 18" is being taken up for the overflow/skimmer/filtration chamber. This leaves me 24". How much space should I devote for the return chamber?

Rich

[Hawkdl2]

Rich,

IT depends on the size of your main tank. If this is supporting a 5 gal nano, then not much. If it's supporting a 300, then as much as possible. I just built a sump for my 150 gal and made the mistake of being more interested in cleaver engineering than the size of the sump portion with the return outlet. Consider that this portion of the sump is the portion that will respond to evaporation and drop in water level. The rest of the system will stay constant (until the return pump stops circulating water). I am losing 2.5 gallons per day and this portion of my sump holds maybe 4 gallons. Although I now have a larger holding tank and top off valves to automate refilling, I wish I had made this section a minimum of 10-15 gallons. If my return pump fails while I am out, my return pump will stop circulating water less than 2 days. Not good.

So, calculate how much evaporation you expect and plan for as many multiples of that as you feel comfortable with. JMO, but I would plan for at least 3x your evaporation rate., maybe more.

[edwardlmarshall]

Good answer. Make sure that the return is roomy enough for your pump (if submersible). 24" is a lot more room than you need for the return, IMO, so why not plan for the future and leave an extra chamber/chambers for a calcium reactor, ozonator, or any other cool gadgets you might think of down the road.

[WolfieCA]

Thanks for the tips.

This sump is being setup for a 125G fish and inverts w/LR and DSB. I am trying to save some space for exactly what you're mentioning Ed.

How high should the baffles be. I was thinking of 8 to 9 inches. Is this too high for a 13" high tank.

Right now I am thinging 18" for the overflow/skimmer/filtration chamber, 10 inches free, and the 14" for ther return chamber with 2 baffles (over/under) before it.

Sound about right?

Thanks again for the advice.

Rich

[Hawkdl2]

Rich, I strongly suggest you "calculate" the appropriate volumes and heights of the various compartments of your sump, rather than simply build what "sounds good". In addition to my first caution, consider calculating how much water will flow back to the sump when you turn off the main pump (or more importantly when it decides to turn itself off). Make sure that the room left in your sump above your partitions is sufficient to hold the flow-back volume of the tank. This is often more than people anticipate.

Also consider that some in-sump skimmers are water depth sensitive. You should inquire with the manufacturer before you build your sump, although what you propose seems reasonable.

[WolfieCA]

At the risk of sounding ignorant, how might I calculate that amount?

Thanks again,
Rich

[Hawkdl2]

There are "calculators" at the top of this web site that will let you calculate tank volumes. Instead of using the actual height of your tank, use the distance from the top water level to the middle of your highest return outlet. This distance should be a couple of inches or less. Do the same for you sump, only measure from the top of your dividers to the top of the sump. The tank number tells you how much water may siphon back to the sump and the second will tell you if you need to invest in a big mop. You don't really need to know the cubic inches to gallon conversion, so alternatively, just multiply W X D x H of each "space" and insure that your sump is equal to or greater than that of the top couple inches of your tank.



Also, for this very reason it is very wise to drill a small vacuum break hole in a return flex line (or any underwater return line) near the surface to break the vacuum and minimize the amount of water that gets sucked back to the sump.

[WolfieCA]

Yo a know, it's amazing how sometimes the obvious eludes. Thanks for the information.

Checked out the levels, and it looks like I have the potential for 11-12 gallons of backlow to the sump in case of a power outage. With using 8" baffles, that will give me about 18.9 gallons of reserve in my sump. Is this a safe area?

Thanks again for the explanations.

Rich

[Hawkdl2]

Rich, sounds like your safe. It wouldn't hurt to test your calculation, though. ONce your tank and sump are hooked up, turn off the pump and let it back flow. That way you'll now for certain that you are OK.

Larry