Sump Filter Question

[monkey_wrench]

Hi,

i was just wondering if the pump in the sump was too powerful and sucked more water
out of the sump at a higher rate than the overflow was taking water in.. would it suck all
the water out of the sump?

I have no idea what the right flow rate pump i need..

thanks for your help

=]

 

[waterdrop]

Post in the hardware section monkey_wrench, there are members over there that know how to design these things. (probably you already found that section )

~~waterdrop~~

 

[JoshH]

It would drain the sump and flood the tank afaik!

 

[OldMan47]

If you could manage to pump water faster than it can drain, then yes it could empty the sump. The real challenge would be finding a sump pump that powerful. The usual situation is that the overflow runs only partially full with the pump running at its maximum flow. If you put a bigger pump in the sump, the overflow runs a little more full. If the flow drops off, the overflow doesn't run as full because there is less water to overflow. Unless the system is badly out of balance, the overflow will easily keep up with your pump.

 

[monkey_wrench]

If you could manage to pump water faster than it can drain, then yes it could empty the sump. The real challenge would be finding a sump pump that powerful. The usual situation is that the overflow runs only partially full with the pump running at its maximum flow. If you put a bigger pump in the sump, the overflow runs a little more full. If the flow drops off, the overflow doesn't run as full because there is less water to overflow. Unless the system is badly out of balance, the overflow will easily keep up with your pump.

oh cool thanks

 

[mike os]

or you reduce the output with a tap.....

 

[waterdrop]

Hi OM47 et. al.,

I've never owned a sump filter but have been fascinated looking at them in shops and pictures of them and the various types of overflow boxes etc. Is it possible you could describe to us in words how the flow works? I'm sure lots of beginners here, not just me, would be interested.

I'm thinking it would be easiest to describe a simple system where there is a simple overflow box hanging on the backside of the tank with I presume a siphon going into it from the tank a and some sort of hose going down to the sump. Then the sump of course has a last chamber where the pump sits and pumps water back up over the tank edge into the tank. I presume the overflow box somehow handles the emergency situation where the pump cuts off. Somehow that keeps the entire tank from then draining to the sump and overflowing into the house, right? So basically, the key part of the question is, what's the trick at the overflow box that accomplishes this safety if that's what it is?

~~waterdrop~~

 

[andywg]

This article explains how an overflow works. The syphon is between two small areas of water, one inside the tank and one outside.as the level of one raises, so does the other causing water to drain.

The above site has the below gif to illustrate:

As you can see, it is certainly possible fo rthat essential syphon to break causing all sorts of problems. This is why all my tanks are drilled.

 

[waterdrop]

Wow, how clever! I did not realize the overflow boxes worked via the dual chambers, I had looked at overflow boxes but just never paid attention.

So why would a system via a drilled tank be better?

~~waterdrop~~
(asking this prior to reading the full link, apologies if its answered in there...)

 

[mike os]

because syphon boxes are not 100% reliable, they sometimes loose syphon & then stop working, also they are very expensive compared to getting a tank drilled.

 

[xxBarneyxx]

If the tank is drilled it is not counting on the syphon to function (it just "overflows" when the water level is high enough). With an overflow box if the syphone breaks it stops working but the pump will carry on pumping water from the sump to the display tank (most likely flooding it in the process and then burning out the pump once the sump is empty).

Drilled tank is a much better solution and I personally would never trust an overflow box (though I have considered them in the past).

 

[waterdrop]

Oh, ok, I'm being a complete idiot here, lol. I was picturing "drilled" to mean holes drilled in the bottom floor of the tank, meaning the whole tank could drain out if something when wrong with the sump system below, but you're obviously describing tank holes that are drilled somehow in the sides(?) after taking into consideration the volume of the sump perhaps so that a bad situation would stop prior to becoming an even worse situation, lol.

Now this would make sense compared with what I've already learned about "weirs" and "overflows" which work in a pretty obvious manner (Whoh!, hold on, perhaps the "drilled" business is making an assumption that the tank has an overflow up in the tank part, is that it?)

~~waterdrop~~

 

[andywg]

Tanks can be drilled in the bottom or the side. I prefer to drill the bottom. To prevent the whole tank draining you utilise a weir so the water level only drops an inch or so once the return pump is turned off.

Below is an image of the first drilled tank I set up where you can see the weir and the standpipe (to reduce noise)

 

[xxBarneyxx]

Good idea using airline on the top of the durso, hadn't seen that done before but it is probably a really good way to control the flow rate.

 

[waterdrop]

O great, lol! I get to feel smart for one minute that I figured out the weir thing before having to be told but then immediately I feel clueless again trying to figure out the clever looking gray pipe. And then Barney comes along mentioning something called a "durso" and now I know I haven't even got the vocabulary

I'm especially intrigued that you mention noise control as that's always been one of the turn-offs about weir/overflows - that you potentially get random waterfall noise, so its not as quiet as a typical external cannister filter.

What is the downward pointing crook opening?... Guess I'm going to need a full explanation of what's going on with the gray thing because I certainly cannot figure it out! And of course the airline and Barney's comment mean there are even more details to hear about! Bring it on, I'm ready!

~~waterdrop~~