Low flow sump

Hey Fish Lore community,

I just had an idea and I'm wondering what your opinions might be.

Let's say you have an aquarium with a sump. Usually you pump a lot of water from the end of the sump into the display tank, say 100gph, and this water goes back to the beginning of the sump through overflow.

Now would it work if you only pumped about 4gph into the display tank, but 96gph from the end of the sump back to the beginning of the sump? Theoretically, the little water pumped back into the display tank would be much much cleaner, so it probably wouldn't be as efficient as the usual way of doing things, but it seems to me that it would work quite well still.

The use for this? Having a much smaller overflow "box" installed on a tank, so it could be much prettier (see ), having much much less flow inside the display tank (useful for some species).

 

You could do that but the sump would have to be able to handle the flow ntm it will be a pain to get the flow right. Once accomplished you would be fine with regular maintenance. I read a thread here where somone use drip system by taping into their can filter. Ill have to look for it.
Lol nvm that was you... did it work out for you?

 

Yep, drip system works perfect, but now I'm thinking that if I do what I'm explaining here, I could get rid of one more piece of equipment in my display tank: the inlet for the filter. My small glass overflow could handle 4gph, and then the sump would just overfiltrate that 4gph by passing it over and over inside the sump.

I don't know if I make myself clear so I made a little drawing:

 

How would you get it to do 96 GPH inside the sump?

 

With a pump. It doesn't have to be precisely 96gph, just the highest flow it can handle without emptying the last chamber.

And likewise, it doesn't have to be 4gph going to the display tank, just the highest flow the miniaturized overflow can handle.

Look at how this guy tests his sump: his return pump just returns the water to the beginning of the sump. I'd use the same principle, but a second smaller pump would handle the 4gph to the display tank.

 

I think the best wy to achieve this is with one pump. Two would be complicated. Id put a ball valve on DT return and sump return leaveing both open. This waythe majority of the water would go to the sump, easiest path for water. Then adjust how much makes it to the top with DT return valve. I would be grabbing an insane gph pump though. If you want low flow get a smaller pump.

 

What would you accomplish by running the same water through your sump over and over?

 

What would you accomplish by running the same water through your sump over and over?

Cleaner water. It doesn't get cleaned in one go.

 

It's also not going back to your tank.

 

The water is constantly re-run through sump after going through your tank anyway. With such a low GPH to and from the tank, it seems that the tank wouldn't be cleaned very well.

 

This is why in theory we filter our water 5 to 10 times per hour to achieve maximum filtration. The main reason for sump returns are to feed differnt eqipment in salt water tanks. The second reason is to reduce amount of water flowing to the display tank if there's to much current. Some also do this to keep the flow over live rock and corals kept in sump as well. Its not really meant to re filter the water.

I have one on my freshwater tank but because I knew when I increased my turnover I would most likely not be able to handle that flow in my drain pipes. With my new pump 2400 gph I had to dial down the amount of water going up. That's what I use it for. Even though I replaced that pump with 1800 gph, I still have just incase. But I'm not using it atm.

 

I see your doubts, but I still think this could work.

I know water is a fluid but try and imagine 1 gallon as an entity. Say this 1G contains 50ppm of whatever that needs to be removed. After 1 go through the sump, it now contains 25ppm of it, second go, 12.5ppm, and so on and so on until at some point it is pumped into the display tank with very very low ppm of that thing we wanted to remove.

With a regular sump setup, this 1G is returned to the tank after the 1st pass, so with 25ppm remaining. But then sure, it's going to go back to the sump much quicker than with my setup.

I feel like the solution I'm proposing is not as efficient than the regular sump setup but is still totally workable.

 

Ideally we should have a high flow filter for mechanical filtration and a low flow filter for bacterial filtration. In most set-ups for flow is to high for the bb to have their maximum effect.

 

I see your doubts, but I still think this could work.

I know water is a fluid but try and imagine 1 gallon as an entity. Say this 1G contains 50ppm of whatever that needs to be removed. After 1 go through the sump, it now contains 25ppm of it, second go, 12.5ppm, and so on and so on until at some point it is pumped into the display tank with very very low ppm of that thing we wanted to remove.

With a regular sump setup, this 1G is returned to the tank after the 1st pass, so with 25ppm remaining. But then sure, it's going to go back to the sump much quicker than with my setup.

I feel like the solution I'm proposing is not as efficient than the regular sump setup but is still totally workable.

Using your numbers for filtration at 50% efficiency in the sump...

Assume, to make the math easier, that your options are 100 gph through the whole system, or 4 gph to the tank, and 96 gph back through the sump (again, your numbers). And let's call the tank+sump 25 gallons.

So you have 25 gallons of water with "50ppm" impurity in it.

Traditional system will turn over all this water (25 gallons) in 15 minutes (based on 100 gph). So at 15 minutes you now have 25ppm impurity in your tank based on your 50% efficiency number.

In the low flow sump, in 15 minutes you have 1 gallon super clean, call it 0ppm. You still have 24 gallons virtually untouched in your tank. So your system will be closer to 48ppm impurity.

What am I missing that makes this a good idea?


EDIT:

To put it another way. In your system, you are removing 4% of the impurities from the tank in the same time that a regular system would remove 50% of them. Right?

 

Ideally we should have a high flow filter for mechanical filtration and a low flow filter for bacterial filtration. In most set-ups for flow is to high for the bb to have their maximum effect.

Which is why I have as much surface area for bb to grow as possible. Another reason sumps are good means of filtration.

 

Surface area has little effect if the water moves over it too fast. Contact time is the most important thing with bb.

 

Using your numbers for filtration at 50% efficiency in the sump...

Assume, to make the math easier, that your options are 100 gph through the whole system, or 4 gph to the tank, and 96 gph back through the sump (again, your numbers). And let's call the tank+sump 25 gallons.

So you have 25 gallons of water with "50ppm" impurity in it.

Traditional system will turn over all this water (25 gallons) in 15 minutes (based on 100 gph). So at 15 minutes you now have 25ppm impurity in your tank based on your 50% efficiency number.

In the low flow sump, in 15 minutes you have 1 gallon super clean, call it 0ppm. You still have 24 gallons virtually untouched in your tank. So your system will be closer to 48ppm impurity.

What am I missing that makes this a good idea?


EDIT:

To put it another way. In your system, you are removing 4% of the impurities from the tank in the same time that a regular system would remove 50% of them. Right?

Yeah I ended up doing the same math. The only way this could still work is if allows for more contact time with the BB somehow. Thus in the case or regular 100gph you would have a less ratio of cleaning than in the split gph case.

I still feel like this is an idea worth digging into but it needs something more to make it work.

Like maybe pump a lot through mechanical filtration to remove impurities (polyester does a great job of polishing your water) and this is where the 96gph pump is at work, and then let it sit a long time with your biological media (long contact time) before pumping it back into the tank (at only 4gph, thus the long contact time). Wouldn't that increase this setup's efficiency?

 

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EDIT: forgot to edit before --- but I have nothing to add anymore. I don't know enough. there is information out there in the reef community for flow rates in a sump. maybe they have more guidance

 

High flow rate in sump isn't going to increase contact time with bacteria... Water will swish by. Low flow in to main tank defeats the purpose... Sounds like you are trying to replicate an AquaClear design using a sump. Totally unnecessary. There is no "by pass" in a sump... Or canister.. In an AquaClear water by passes the media, you need high flow rate you ensure all the water actually makes it through the filter at some point. You don't need as high flow rate for sump or canister because there is no by pass.

Might be a fun experiment, but I can think of more useful uses of time...

 

There are bypasses in sumps, there purpose is not for extra filtration though. Its normally used for reducing flow to main tank. Its used commonly on large tanks, when the pumps are strong enough to create to much current in tank or overflow cannot handle the flow. Its a safe way to reduce flow without adding extra wear to pump. Some pumps don't come with flow adjusters so reducing flow directly with valve can cause unnecessary wear. That's their purpose. In this case it would not be functional. It can be and is useful When used properly.