Water movement due to an airlift and center bottom drains:

Preview directly after some pond and filter changes 2018:

## Franks pond 2018

### Re: Franks pond 2018

Hey Frank,

Looks very impressive! Could you share some more details on your filter? What techniques have you used exactly?

Looks very impressive! Could you share some more details on your filter? What techniques have you used exactly?

### Re: Franks pond 2018

It's an custum made endless belt filter,

Inlet: 3x 160mm for bottom drains, 1x 110mm for skimmer

Outlet: 1x 315mm

Belt: 100µm Sefar mesh

Max.: 100.000 l/h

I use the filter for 60-65.000 l/h therefore I have 2-3 cm difference only before the next cleaning.

Besr regards,

Frank

Inlet: 3x 160mm for bottom drains, 1x 110mm for skimmer

Outlet: 1x 315mm

Belt: 100µm Sefar mesh

Max.: 100.000 l/h

I use the filter for 60-65.000 l/h therefore I have 2-3 cm difference only before the next cleaning.

Besr regards,

Frank

### Re: Franks pond 2018

My result is 65m³/h with 90 Watts. Is it okay?

Frank

Frank

### Re: Franks pond 2018

Hey Frank,

In absolute perfect conditions you could get up to 20.000 litres an hour with one Airlift running at 12W.

So that would mean 65000 / 20000 = 3,25

3,25 x 12W would give a theoretical maximum efficiency of 39W for that output, however, you can't run 3,25 Airlifts of course, so this is very theoretical.

I would say the best possible real life result you could achieve which is close to what you are getting, would be 3 Airlifts running at 12W pumping 20.000 liters an hour, so 60.000 liters at 36W.

In the real world you have to calculate for filter drag though, and these values are measured with the Secoh-SLL20 pump. I don't think you are running 3 Airlifts on the Secoh-SLL20 pumps.

Before I can say much about your values, I must know how you measured your flow? Did you measure it with the filter fully stocked with material or not? Do you think that all of your transits are big enough?

Greetings!

In absolute perfect conditions you could get up to 20.000 litres an hour with one Airlift running at 12W.

So that would mean 65000 / 20000 = 3,25

3,25 x 12W would give a theoretical maximum efficiency of 39W for that output, however, you can't run 3,25 Airlifts of course, so this is very theoretical.

I would say the best possible real life result you could achieve which is close to what you are getting, would be 3 Airlifts running at 12W pumping 20.000 liters an hour, so 60.000 liters at 36W.

In the real world you have to calculate for filter drag though, and these values are measured with the Secoh-SLL20 pump. I don't think you are running 3 Airlifts on the Secoh-SLL20 pumps.

Before I can say much about your values, I must know how you measured your flow? Did you measure it with the filter fully stocked with material or not? Do you think that all of your transits are big enough?

Greetings!

### Re: Franks pond 2018

Hello,

12 Watt for 20000 l/h is without any filter activity possible! As soon as you have bottom drains you loose 2-3 cm, additionally 2 cm at the mesh of the filter and 2 cm on the bio chamber. That means my head is 6cm and therefore the result should be fine.

I use three THOMAS AP 60N, which is the most effective air pump in my large serie of measurements since SLL 20 is not available any more and also not that effective.

The airlift is 250mm in diameter and 170cm long with 300mm air disc of Supratec.

Best regards,

Frank

12 Watt for 20000 l/h is without any filter activity possible! As soon as you have bottom drains you loose 2-3 cm, additionally 2 cm at the mesh of the filter and 2 cm on the bio chamber. That means my head is 6cm and therefore the result should be fine.

I use three THOMAS AP 60N, which is the most effective air pump in my large serie of measurements since SLL 20 is not available any more and also not that effective.

The airlift is 250mm in diameter and 170cm long with 300mm air disc of Supratec.

Best regards,

Frank

### Re: Franks pond 2018

Thanks for sharing!Frank wrote: ↑06 Jun 2019, 12:49Hello,

12 Watt for 20000 l/h is without any filter activity possible!

Yes that's what I meant. In real life you will always have losses. The trick is to minimise your losses.

As soon as you have bottom drains you loose 2-3 cm,

How many bottom drains do you have connected to the Airlift?

additionally 2 cm at the mesh of the filter and 2 cm on the bio chamber.

That means my head is 6cm and therefore the result should be fine.

I agree, it's not a bad result!

I use three THOMAS AP 60N, which is the most effective air pump in my large serie of measurements since SLL 20 is not available any more and also not that effective.

So you think the Thomas AP 60N is a better performer than the Secoh SLL-20? Interesting, would like to test one.

The airlift is 250mm in diameter and 170cm long with 300mm air disc of Supratec.

So, your Airlift is a membrane design then. Good to know.

And I can see in your video that you use those three pumps in conjunction to run this single Airlift. Do you think this works better than a single more powerful pump? I don't think I've seen this setup before but it makes sense.

Best regards,

Frank

### Re: Franks pond 2018

Good morning,

I have three bottom drains 160mm each and one 110mm skimmer. One bottom drain delivers approx. 18.000 l/h with 2 cm level loss only. If you go deeper (e.g. 15.000 l/h) to reduce the loss, the flow rate might be too less and the pipe could clog. A 160mm bottom drain equals to 2 x 110mm.

The THOMAS AP 60N makes 47 l/min with 31 Watt at 200 mbar (< 0,7 W per l/min) and this the best result at 200 bar in my tests. Similar effecient is the Aquaforte AP 60 with 35 l/min at 24 Watt (< 0,7 W per l/min). By the way the Secoh SLL 20 brings at 200 mbar no air at all, good results I see at 150 mbar. Why do I measure at 200 mbar? That is quite easy, 170 cm (170 mbar) due to the airlift pipe plus 30 mbar air membrane resistance. For your 110mm air lifts these two air pumps might be too strong, I don't know exactly. For my application these pumps fit very well because I use them in parallel. In general air pumps become more

Now back to my pond. I "loose" approx. 2 cm at the bottom drains and 2 cm at the sieve. That is less and I could not reduce anymore. Additionally I loose 2 cm at the bio chamber, because the airlift blasts into the bio and from there the water goes back to the pond. The advantage is, that the air could escape easily and the bio media is moving by the power of the air lift. That's the reason why I build it in this way. The disadvantage is the loss of another 2 cm discharge head. Maybe I will change this in future to come done to 4 cm all over discharge head.

Best regards,

Frank

I have three bottom drains 160mm each and one 110mm skimmer. One bottom drain delivers approx. 18.000 l/h with 2 cm level loss only. If you go deeper (e.g. 15.000 l/h) to reduce the loss, the flow rate might be too less and the pipe could clog. A 160mm bottom drain equals to 2 x 110mm.

The THOMAS AP 60N makes 47 l/min with 31 Watt at 200 mbar (< 0,7 W per l/min) and this the best result at 200 bar in my tests. Similar effecient is the Aquaforte AP 60 with 35 l/min at 24 Watt (< 0,7 W per l/min). By the way the Secoh SLL 20 brings at 200 mbar no air at all, good results I see at 150 mbar. Why do I measure at 200 mbar? That is quite easy, 170 cm (170 mbar) due to the airlift pipe plus 30 mbar air membrane resistance. For your 110mm air lifts these two air pumps might be too strong, I don't know exactly. For my application these pumps fit very well because I use them in parallel. In general air pumps become more

**in**effective the bigger they are, but smaller than the mentioned ones are also not possible for me because they bring no or less air at 200 mbar.Now back to my pond. I "loose" approx. 2 cm at the bottom drains and 2 cm at the sieve. That is less and I could not reduce anymore. Additionally I loose 2 cm at the bio chamber, because the airlift blasts into the bio and from there the water goes back to the pond. The advantage is, that the air could escape easily and the bio media is moving by the power of the air lift. That's the reason why I build it in this way. The disadvantage is the loss of another 2 cm discharge head. Maybe I will change this in future to come done to 4 cm all over discharge head.

Best regards,

Frank