Ideal turnover or flow for an powerhead operated undergravel filter?

[bela]

This thing is making me nuts.

I have a 40 gallon breeder tank with undergravel filter. Two uplifts. On each uplift I have got a 132 gph powerhead.

Those are the smallest I could find. They have ajdustable power/flow.

My question is if you would run the powerheads at 100% power, 50% or 25% or if it does not really matter that much.

Please chime in

[Zenzo]

On 2/23/2022 at 8:27 AM, bela said:

This thing is making me nuts.

I have a 40 gallon breeder tank with undergravel filter. Two uplifts. On each uplift I have got a 132 gph powerhead.

Those are the smallest I could find. They have ajdustable power/flow.

My question is if you would run the powerheads at 100% power, 50% or 25% or if it does not really matter that much.

Please chime in

My opinion is that flow rate for filtration is overrated. It is my belief through my fish keeping experience, that the amount of surface area water passes through is more important than the rate in which water is moved. For example, if I have a sump that is packed with media, and water passes through at 200 gph for a 75 gallon tank, many people would say that it is not enough. But, the water is actually touching more surface area and beneficial bacteria than a much smaller filter that is moving 600gph. 

With your under gravel filter, you essentially have the entire floor of the tank and the substrate as the surface area, so I don't think that the rate in which the water passes through is critical for biological filtration. 

I would set the flow to what is best for the movement in the aquarium as far as the fish, surface agitation, etc.

[lefty o]

with 2 of them, i would try at the 25% setting. i like water flow, and lots of filtration, but you must meet the needs of the fish. if the filters are blowing the fish all over the tank, and they cant find a space to rest, thats a problem. id start 25% on each, and if that doesnt seem to be enough, turn one up to 50, if still not enough turn the other up to 50 too, repeat as needed.

[bela]

On 2/23/2022 at 6:52 PM, lefty o said:

with 2 of them, i would try at the 25% setting. i like water flow, and lots of filtration, but you must meet the needs of the fish. if the filters are blowing the fish all over the tank, and they cant find a space to rest, thats a problem. id start 25% on each, and if that doesnt seem to be enough, turn one up to 50, if still not enough turn the other up to 50 too, repeat as needed.

Do you think it would be fine with just one uplift?

[lefty o]

it would probably be fine with 1. my own thinking though is if there are two up tubes, i would try and get flow from both so as to draw more evenly across the bottom thru the under gravel filter.

[Wrencher_Scott]

On 2/23/2022 at 11:11 AM, bela said:

Do you think it would be fine with just one uplift?

Yes, one power head is plenty for the UG. Just plug the other one of course.

Have you thought about just using air instead? You get flow and aeration, a win-win if you ask me.

[Widgets]

On 2/23/2022 at 11:27 AM, bela said:

I have a 40 gallon breeder tank with undergravel filter. Two uplifts. On each uplift I have got a 132 gph powerhead.

My question is if you would run the powerheads at 100% power, 50% or 25% or if it does not really matter that much.

I have a 37 gallon tall. It has the same footprint as a 20 gallon long. I have an undergravel filter with dual power heads rated at 127 gph each and running at 100%. I also have an aquaclear 110 HOB full of 15 ppi sponge also running at 100%. I currently have harlequin rasboras, zebra danios, a siamese algae eater, and some red cherry shrimp. They do not seem to have any problems with the flow.

I can understand the thought that a lower flow rate will give the water more contact time with the beneficial bacteria on each pass, but also note that the higher flow rate will bring more oxygen to the beneficial bacteria. If you have a decently planted tank, the roots of the plants will also provide oxygen.

I don't think anyone fully understands the science of what is happening in our tanks. Each tank is its own little ecosystem, and no two tanks are exactly identical. You can research and ask questions to get a starting point, but you have to experiment and observe to find what works best for you for this tank. That is part of the fun of the hobby for me.

Edited February 24, 2022 by Widgets
Typo

[Tanked]

I am pro powerhead for UGFs for the simple reason that I can see them working.   The 132 gph rating is a best case scenario.  Unless stated otherwise, the rating doesn't account for lift or substrate depth or type.  Watching the fish is the best way to determine the flow rate in my opinion.  If the fish are avoiding one area of the tank, hiding, or must constantly swim upstream than the flow is too much.  The powerhead I used for years in my 29 was too much when I switched to nano fish.

One powerhead is probably adequate.  The 40 breeder footprint is not significantly larger than the 29.  Because your flow rate is adjustable, I would continue to use two for the additional turnover through the entire substrate. 

[jasper5150]

This sounds like the place to ask this. I have a 20 gallon high with a sponge filter running. The flow in the tank seems to be pretty low. Lots of mulm on plants. How can I increase flow without using a HOB or power head?  Maybe add an additional air stone/sponge filter to the opposite side of the tank?

[Widgets]

@jasper5150 I would try to optimize the sponge filter that you have first. If you don't want to use a HOB or power head or canister, you will probably need to use a second sponge filter. There are benefits to running two sponge filters, such as having an extra cycled sponge filter to use in an emergency quarantine or hospital tank.

 

 

[jasper5150]

@Widgetsafter I asked, I remembered I hadn’t cleaned my sponge filter in quite some time. Able to squish quite a bit of debris out of it and adjust the Ziss air stone inside. The flow is very good now. I will be adding an additional sponge filter soon just for the reason you mentioned. I have watched the video you tagged. So many good tips and advice. Thank you for taking the time to answer!

[Andy's Fish Den]

If it was my tank, I would use both powerheads. If the UG filter was designed with two uplift tubes,, I would use them to get equal flow across the tank, especially of the filter has two plates that sit next to one another or connect. If you think about it, if you have one uplift tube in one of the back corners, how much flow is it going to pull from the corner diagonally from it? I would want to get as much flow through the gravel as possible, otherwise it would be like in a canister or HOB filter that has water channeling and not going through the filter media the best.