Backyard Aquaponics
A place to discuss aquaponics

Frank, I need to address your blatant accusation that I am a liar, and then for the good of this forum I am only too happy to completely ignore you - you will be the first and only member that I have added to my ignore list.

As proof that this accusation is completely false - I have attached the cover page of Reinamann's phD Thesis.

To make such an accusation and then sincerely offer friendly greetings is not something that I believe is acceptable in my culture, perhaps it is in yours Frank?

nice try, Rupert


at the moment I am using centrifugal pumps in my system, each of them located in the bottom (sump) tank, in which I also keep crayfish
the setup is fully in development
for now it is:
1000 liter IBC fish tank standing on the floor, (water level at about 1050 mm from floor thanks to the pallet) -overflow to 6 parallel NFT 7 m long PVC 100 x 100 mm square tube , holes dia 90 mm drilled every 125 mm in the top of the gutters, gutters mounted level at about 900 mm height, DIY automatic float ebb and flow valves (design posted-work perfectly) on the end of each gutter (water height variation between 20 and 60 mm), all six draining into a collector which spills into a growbed made of 1/3d of an IBC tank laid on it's side (I just cut out the middle strip of the IBC that holds all the openings), supported at about 500 mm bottom height (800 mm plant working height) by a table frame (legs shortened) that stands straight in the other 1/3d of the IBC tank which stands on the floor turned 90° so it sticks our from under the growbed (surface 1000 x 1200 mm) and serves as a sump. Growbed drains into the sump below it. Pump in sump (with crayfish) pumps water back to Hozelock pond filter standing on top of the fish tank IBC and overflowing into the IBC.

planned modification:
IBC fish tank standing on the floor, overflow to solids settling tank incorporating floating beads (replaces Hozelock pond filter - see other thread), which overflows to the 6 parallel (100 mm distance) NFT 7 m long gutters at about 900 mm height, DIY automatic float ebb and flow valves on the end of each gutter, all six draining into a collector which spills into a growbed at about 500 mm bottom height. Growbed drains into the sump below it. Pump in sump (with crayfish) pumps water straight up ca 700-800 mm head to level return NFT gutter straight above ca. 8 m long standing on top of the fish tank IBC at ca. 1100 mm height and overflowing into the IBC. Control by level switches on the sump, which will also control a solenoid valve to top off the tank for water consumed by plants or lost by evaporation.
Next expansion: similar setup on the other side of the fish tank. That will double circulation volume and plant surface.
This will be my plant nursery, since the holes in the gutters are very close to each other.

Next (parallel) to that will come 3 more similar systems, but with more growbeds than NFT gutters.
all systems controlled and guarded by PLC (probably Siemens LOGO!) with SMS alarm reporting.
All under a double walled plastic foil greenhouse (realizing that stays a big challenge, a brain buster).

Can you picture it?

And yes, for the moment I have a blower running air stones in the fish tanks for extra security, but I will put that on emergency backup for should a pump break down .

now you have me fully exposed what with centrifugal pumps and a blower and air stones...

But I intend to try and build my own propeller and/or piston pumps because I hate energy waste and would like to take the system on 12 V and off the grid, or at least have a battery backup, so every single watt counts.

friendly greetings

Frank

Gee I'm glad i stayed out of this one:)

You guys seem to be squeezing and battling over wording and such what.

I have added some links , and i willingly stand by my opinion ( formed by facts) that propeller pumps are more efficient that air-lift pumps.

Just think of the things powered by propellor type pumps ,, JET engines come to mind,,Prop planes ,,Boats/ships / sub-marines are another.There must be some form of efficiency in propellors for them to be chosen for so many tasks.

If air-lift style pumps are so wefficient ,, then why are they not seen doing work in everyday life?

Myles ,, i'm not looking for an argument , nor dismissing your opinion ,, I merely ask questions and state facts.

Rupert ,, i run one air-lift on one of my Lakes in Thailand ,, this was before I made a U-tube air reactor,,,The u-tube , even using a realatively inneficient pump wins hands down

Guys please keep it friendly ..... I'm suppose to be the bad guy here ,, your ruining my rep..

Did you ever post a diagram of that U-Tube reactor Chappo... can't find it....

what is a u-tube (air???) reactor?

excuse my ignorance

frank

Frank

Its a counter flow device. Water with oxygen/air is pumped downwards (to be effective it has to be over 30ft depth) then it rises back to the surface on the other leg of the utube. Normally just a pipe inside a larger pipe, down the centre pipe and up between the inner and outer pipe.
There's a description in one of the SRAC papers.

Just skiped some pages, what did I miss.

Anyway I have an inground pool and have a 1000lph pumb that I put on the bottom and a 15$ small air pump running an air stone. After a couple of minutes I noticed that I could only tell that one was moving water to the surface. So I'm going to put in a air blower with a long soaker hose to kill two birds with the one stone. It will add air to the system and moved a lot of water in my 55kl system. Even my 3hp pool pump will not move the same amount of water. And the air blower is cheaper to run.

myles - Hit the button, it saves a lot of grief!
...oh and a shirt load of unneccesary reading!

Did you put a standpipe on the 1000 lph pump exit right to water level, Dufflight?
The airlift pump has a standpipe right to water level, I would think
You must compare similar situations before you can draw conclusions

frank

You can see the water displacment. it is the size of a dinner plate.

If you didn't put a standpipe on the centrifugal pump, you will see very little movement on the surface if the pump is at a depth: all it's flow will be spread at depth
you really do need to put that standpipe.

frank

Moved it onto the top step and it still does not displace the same volume of water. Also I think the pump uses more power than one air pump so that would make a difference in favor of the air pump.

On another topic has any one used there air pumps to add heat to the fish tank. Eg air blower to a sealed heater then to the air stones. Warm air bubbles rising in the tank allowing the heat to move into the water. Any heat not passed into the water goes into the room the tank is in. If its a greenhouse it could be used in heating that area. Or if you heat your glass house it could be combined to help with winter water temps and growing enviroment.

It is virtually impossible to judge or compare two such different pumps on eyesight, Dufflight.
To begin with, the impression of the flow of an airlift pump can be very fooling as it is much more turbulent and irregular (due to the air mixed in it, bubbles joining which increases their speed) than that of the centrifugal which will give a more lamina, regular flow. And the impression of flow is also increased by the air bubbles which expand on their way up and explode on the surface.
The flow of the centrifugal pump stays the same on whatever depth it is placed.
the only really conclusive test you can do is to have a pump exit of both pumps to an empty recipient either inside or outside the tank or pond and then time the flow.

Concerning your question on heating the air to heat up the water, it would most certainly be more efficient to heat the water directly as air is a much worse conductor and as you add another conversion. Each conversion means losses and diminishes efficiency. Add to that the heat not passed to the water which as you state is not really lost but still is not converted into warmer water.
Another issue might be that it would probably increase air moisture in the greenhouse which I believe not to be necessary in AP with all the water already moving around. This could lead to extra mould and condensation problems.

greetings

Frank

Thermodynamics will have the heat move across to the water okay. Had a spa mat that worked the same way. Hot air in the bubbles heated up the water. Having to heat the water directly may be a bit more difficult eg pumps elements. The air moving after the air pump could be directed through a heat exchange on just about any heat source. Hell you could run hose in the roof of your house to get any heat lost through your ceiling. Or through pipe around the chimney. Most of the time the water only needs a little help in the winter.

Still it might be fun to play around with.

My 1000 litre tank in the glass house gained heat from 14.5 deg to 15.9 deg and the top temp in the glasshouse was 45 deg and the air pump is pumping from the top shelf the tank was just cycling on its own [tomorrow i will change 200 litres of water]