Filter turnover rate

[Mark Hewitt]

Is there a general minimum turnover rate for filters i.e. the amount of water they filter per hour compared with the volume of the tank? I've read in places that 4x per hour is a realistic minimum? Would you say this is right?

I ask because in my 135 litre tank I've measured the flow rate at 350 litres per hour. Which gives a turnover rate of approx 2.5x per hour. Does this seem a bit low?

I have a TetraTec EX700 external canister filter. I'll go ahead and buy the EX1200 if I need to, but it would cost me another £100!

 

[BigJim]

You can always add another filter. I like to aim for 4x-10x turnover. I've got an AC30 on an 20H and I'm not comfortable with the lack of water movement yet.

 

[CA_BroncoFan]

I just put an ac50 on my 20 long, granted i scaled back the input/output but im happy now. As for my 90 i have not enough water turn over. IMO the better the filtration or more filtration (so long as the fish are not blown out of the tank) the better.

 

[Mark Hewitt]

Unfortunately I spent all my money on the EX700 thinking, if anything, it would be too powerful for the tank. Turns out to be just the opposite

 

[BigJim]

It happens. Manufacturers like to rate filters for extremely lightly stocked tanks rather than real world tanks. Take the rating and cut it in half.

Here's what I run on my tanks:

20H - AC30 upgraded with an AC50 impeller, max flow setting
20L - AC50 upgraded with an AC70 impeller, max flow setting
29g - AC70, max flow setting
40B - AC110, min flow setting for now

 

[Mark Hewitt]

Yep. Ah well! I'm just wondering how much of a problem it's going to be having a 2.5x turnover rather than a higher number?

At the moment my stocking levels are low so it's probably sufficient, but obviously I intend to increase the number of fish I have!

I guess ultimately I'll need to get a bigger / more powerful external filter, but I just haven't got the money for that right now.

In the meantime I have my old internal filter which I could add in there.

 

[BigJim]

Keep an eye on your water quality. If your parameters are in line, the water is clear, and the fish are healthy, you're ok with your current filter.

 

[Floyd R Turbo]

The only thing I've read is that with a planted tank, you want to keep the turnover rate below 5x/hour. Other than that, it's whatever your bio-load will allow. I would think you would be fine with 2.5x/hour even though that's a little low.

 

[Mark Hewitt]

Alright I'll just keep an eye on things then!

I guess one way I could check if things aren't working is to compare the rest results from the tank vs water coming out of the fitler? i.e. If the water from the filter is ammonia free, and there is ammonia in the tank water, then the turnover is insufficient? Does that sound right?

 

[BigJim]

Just measure the tank parameters. They'll be good if the filter is sufficient.

 

[adeebm]

hmm I have an AC70 and an ecco 2234 on my 46g and I though I was going overboard. I guess that's only 3-4x turnover though :/ I would put my penguin 350 back on but it's noisy and annoying lol.

--Adeeb

 

[Mark Hewitt]

Ah rubbish. Just tested the tank water: 0.5 ammonia. But the water out of the filter is 0 ammonia. So it looks like the filter is working, but not removing the water quickly enough.

 

[BillD]

Water readings will tell you whether you have enough filtration. It doesn't matter what the turnover rate is if the filter is maintaining 0 nitrites and ammonia. Keep in mind that every solid surface in the tank whether it be substrate, rocks and decorations, plants or glass, provide surface area for bacteria to colonize and become part of your filter. The combination of all these factors will determine whther you have sufficient filtration. In addition, regular removal of solids from the filter will also reduce the total bioload on the tank by removing the solids before they can be broken down to become ammonia.
You soon discover, if you frequent forums, that everyone knows more about filtration than the manufacturers.

 

[Mark Hewitt]

Ok cheers. Any comment on the disconnect between my filter output and tank readings?

 

[Floyd R Turbo]

How long has the system been up and running?

 

[Mark Hewitt]

That filter has been running around 2 months, although about 3 weeks of that was on my 64 litre tank before I upgraded to the 135 litre.

Reason for getting that bigger filter was I was getting a constant 0.25-0.5 ammonia reading all the time so wanted to upgrade my filtration.

But since then it's been all over the place, ammonia between 0.25 and 2! Test for nitrites and they come in at 0.5 one week then gone the next week then back the week after!

Just did a test and found that now the ammonia is 0.25 in both tank water and filter output, but the nitirtes are 0.5 in the filter output and 0 in the tank! My head hurts, it really does!

I do wonder if these are all symptoms of the water both not being turned over frequently enough, and secondly there not being sufficient flow through the whole tank, as it's quite narrow being 4ft long but only 1ft front to back.

What I might do is get an internal filter, probably a Fluval U2, to give the external a helping hand and to improve circulation a little.

 

[Floyd R Turbo]

Ok, let me see if I've got this right. So you had an established 64 litre tank, you bought the new filter and put it on that tank, then 3 weeks later you got the new 135 litre tank and transferred everything over, so this new tank has been running now for about 5 weeks. Correct so far?

When you upgraded the filter on the 64 litre, did you take the old filter media and put it in the new one to 'seed' it, or were you just running both side-by-side? What about when you started up the 135?

Did you transfer anything else from the 64 to the 135, like gravel, decorations, etc?

I suspect what is happening here is that you are seeing a bunch of mini-cycles. I don't think additional circulation will make a whole lot of difference, just time.

Ok, I just took a few minutes (I should have done this before) and looked up the TetraTec EX700. Is this what you have?

https://www.tetra-service.net/tetra/go/EB6E4F6D15C55F9A8D229E4E478584FF/?lang_id=2

These filters are identical to the Marineland C-series filters that are sold here in the states, which is what I use on my 55 gallon tank. I even watched the video, the only difference is the color of the tubing to and from the canister.

Our Products

This is a very good filter design, I've been happy with it. That being said, I am trying to figure out the comparable unit between the C series and the EX700, but I think it's the C-360. The Marineland version has models 160, 200, 360, and 530. The Tetratec models are 400, 600, 700, and 1200.

What are the dimensions of the filter media that you use? I'm talking about the black coarse pads for the bottom tray or the white polish pad in the top tray. I'll compare them to mine.

If it's the same size, I use that model on my 55 gallon planted tank, and I figured (on paper, at least) that I get about 3-4 turns per hour. So something isn't adding up...somewhere...

PS here's what my C-360 looks like

Is yours about the same size?

 

[Mark Hewitt]

Ok, let me see if I've got this right. So you had an established 64 litre tank, you bought the new filter and put it on that tank, then 3 weeks later you got the new 135 litre tank and transferred everything over, so this new tank has been running now for about 5 weeks. Correct so far?

Right!

When you upgraded the filter on the 64 litre, did you take the old filter media and put it in the new one to 'seed' it, or were you just running both side-by-side? What about when you started up the 135?

Ran the cansiter alongside the internal on the 64 for three weeks then when I transferred everything to the 135 the external transferred to but the internal did not.

Did you transfer anything else from the 64 to the 135, like gravel, decorations, etc?

No gravel, but decorations, and of course fish.

I suspect what is happening here is that you are seeing a bunch of mini-cycles. I don't think additional circulation will make a whole lot of difference, just time.

OK, you might be right, but my main question is, is 2.5x hr sufficient in the longer term?

Ok, I just took a few minutes (I should have done this before) and looked up the TetraTec EX700. Is this what you have?

https://www.tetra-service.net/tetra/go/EB6E4F6D15C55F9A8D229E4E478584FF/?lang_id=2

That's the ones , yes.

What are the dimensions of the filter media that you use? I'm talking about the black coarse pads for the bottom tray or the white polish pad in the top tray. I'll compare them to mine.

If it's the same size, I use that model on my 55 gallon planted tank, and I figured (on paper, at least) that I get about 3-4 turns per hour. So something isn't adding up...somewhere...

Not sure what the pad sizes are (at work) but the external dimensions are 420H 205W 210D

PS here's what my C-360 looks like

Is yours about the same size?

Impossible to tell from that picture. Here's mine

http://www.flickr.com/photos/markhewitt/5279900820/in/set-72157624968569563/

 

[Floyd R Turbo]

That actually looks a little smaller. It might be the version comparable to the C-220. That wouldn't make much sense though, because there are 4 sizes of each different brand and the 700 is the 3rd size, as is the C-360.

Still, I would think that the comparable size to the C-220 should be plenty of filtration capacity for a 35 gallon system.

I think your issue is that your filter did not run long enough on the other tank to establish a good enough bacterial colony. What you should have done when you transferred the tank is put the filter media from the old tank into the 700. Since your system was running an established filter, that one was handling all of the current bio-load, so the new 700 filter probably didn't have enough of a 'food source' to sustain a bacterial colony to support the full load of the system when the older filter was removed as you switched tanks. You might have had something like 20% of the bio-filtration taking place in the 700, and 80% was taking place in the old filter. Putting that 20% filter on the new system by itself will cause a cycle that is more than a mini-cycle, but less than a full-blown cycle.

Variations in the output of waste and in input of food into the system could explain variations in the ammonia level in the tank and the ammonia level at the output of the filter. It doesn't explain an ammonia-free tank and 0.5ppm ammonia out of the filter, however. That could be an error in the test, or something else like waste trapped first stage of the filter that is breaking down and not getting consumed by the last 2 stages (balls and rings).

Eventually, I think the filter will catch up. You will just have to watch the Ammonia and NitrIte levels, and do a PWC if you see anything over 0.5ppm Ammonia or any NitrIte whatsoever (NitrIte in a FW tank inhibits oxygen exchange and burns gills, so you don't want it at all)

 

[Mark Hewitt]

Cheers for that. I think we're sorted now anyway. My first 0 ammonia 0 nitrite reading since October!

All the same I've installed a U3 internal filter to help things along. Hopefully all will be well from now on and I won't have to spend time whinging on Internet forums