Need help with the math!

[batman3n1]

Hi Guys,

I have a couple questions about water volume. I know the formula for figuring a tanks size in gallons, but wanted to know how to figure how much water will be drain from the tank when the pumps are stopped. Also how much additional water the sump can accept before an overflow occurs. For the sump, I was thinking the shorter the dividers, the more volume it will hold. Is that true?

Thanks in advance, guys.

 

[cmaxwell39]

You would use the same formula. For the sump, use the empty space it has when the tank is running, and add that up with the lxwxh/231 formula.
If you have multiple chambers, add up the empty space that exists in all the different chambers.

For figuring out how much water would drain out of the display, figure out how far the water is going to fall when your return pump shuts off and use the same formula (use the distance the water will fall as the height measurement.)

 

[Reefing Madness]

The water returning to the sump form the DT would all depend on PVC size and wether or not your using a Drilled Tank or and Overflow, and if your using drilled holes in the pvc to break the syphon. Lots of variables in this equation. Useually its only a couple of gallons that gets back.
Why would the baffles have any difference on how much water the sump would hold? They are basically there to keep a consant water level in one portion of the sump/fuge and to act as bubble diffuser and to throw in media.

 

[TrialandError]

If the tank is drilled just fill the display tank till water starts draining down into the sump. Then fill the sump to capacity. Turn on pumps then when at full operation take a permanent marker and mark the water level. I mark the level on the return pump side so I know how much water needs to be added from eveporation. Then if power goes out there is no possible way for it to overflow.


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[bct15]

To calculate water that will leave the tank with pumps off use the same formula you used to calculate tank volume, except the height will be from the bottom of your drain holes on your overflow to your water line (assuming your using a filled tank).

As long as your baffles don't go all the way to the top of your sump, you'll use the same formula to calculate extra space in your sump. The height will be from the water line in your sump under normal operation to the top of your sump.


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[Reefing Madness]

Melevsreef.com | Acrylic Sumps & Refugiums

 

[AZDesertRat]

L x W x depth of submergence of the return and overflow box teeth / 231.

So say it a 75 or 90 G standard 48" long by 18" front top back tank and your return nozzle is 3/4" below the surface. 48x18x.75/231 = 2.8 gallons. You would always maintain that 2.8 galllons of freeboard or empty space in your sump at all times plus a little extra for a "fudge factor". My 100G drains a maximum of 3.5 gallons back to my 30G sump when the power goes off, 60'x18'x.75" = 3.5 gallons. The overflow teeth are not quite the 3/4" depth of submergence but the returns are so the overflow stops siphoning first followed by the returns.


Forget the drilled holes and check valves, they are a waste of time and a false sense of security. Stick with an air gap where the return is exposed to atmosphere with a slight backflow, its the most foolproof form of backflow prevention known to mane period and zero maintenance or cleaning is ever required.