Ok...I feel pretty stupid asking this, but I can't figure it

[alphadog808]

Hey guys,
I was thinking about getting a wet/dry filter with a sump under my tank. I've looked online, but I still don't think I've found a satisfactory answer that answers my question...

I understand that the water intake from tank to sump is done with suction...no problem there. However, when there is a power outage, I realize the overflow box will only "feed" the sump a certain amount of water(so the sump doesn't overflow). Now, here's my question...

When the power comes back on, how does the tank to sump suction start up again? Or can it? I would think when the power goes out, the suction would grab all the water in the overflow box and then suck air till the suction is broken. When the power comes back on, the filter in the sump will push the water back to the tank, and subsequently the overflow box will start filling up again...but with the suction broken, the sump won't get any more water....right??

 

[chase33]

It doesn't work by suction, it works by gravity. The water in the overflow will drain downward into the sump. It stops when there is no water in the overflow to drain or the standpipe is above the water level. You can only drain what is in the overflow. When the power is out water is not pumping into the tank so it is not going into the overflow so it cannot go into the sump. When the power comes back on the water is pumped from the sump into the tank eventually filling the overflow and by the forces of gravity, flowing downward into the sump.

 

[alphadog808]

chase, thanks for the reply.

I guess I should be more clear...the tank to sump is done by gravity, not suction. I've done this in the past when draining my tank or doing some cleaning, etc...however, I noticed that when I got near the bottom of the tank(almost no water left), the hose would start grabbing air along with water...once I got enough air in there(due to lack of water left), I wasn't able to get any more water to go through...

As in the above, what I'm wondering is when the power goes out, the overflow box gets emptied by the gravity "suction" in the "candy cane"(haha) tube. I assume the overflow box will get emptied(till like the above example, too much air gets in) and the water will not restart till the "candy cane" is primed again...

Maybe my confusion lies in how the water gets from the overflow box to the sump...but from what I've read, it's similar to like what I mentioned above...like how you'd start sucking on the hose to start the water...(ugh, I remember getting a mouthful of water more than once!)

 

[Hara]

actually the J tube sits below where the water level drops in the box and does not lose its prime if it is set up correctly.

 

[ccCapt]

The overflow box doesn't empty completely. There will still be some water in it and the u-tube will still be filled with water. When the pump restarts and the tank starts refilling, the higher water level will push more water into the overflow and it will start draining back into the sump.
Just make sure your sump is big enough and you keep the water level in it lower enough so if the power does go out, your sump can handle the extra water from the tank and not overflow.

 

[alphadog808]

Hara, which side of the J tube is below the water? Also, thanks for the help guys...I think maybe I'll just buy one and assume this works..

 

[Hara]

The tube sits inside a box, which sits inside the tank...the box has slits into it to let water in. The water level is adjusted by moving the box up and down. The tube hangs into the box.

Trust me, they work

 

[melosu58]

I use to have one and they work. They wont lose their prime unless you pull it out and air gets back in there. Many a time the power went out and restarted with no problem.