liveforphysics
New member
Hi guys!
Eductors are a very neat tool for our reefs. They enable a pump to circulate a small amount of water at a high pressure, and turn this pressure into velocity. This fast moving water stream creates a low pressure area, which draws much more water through the nozzle. Often they operate at a ratio between 4:1 to 15:1 depending on the pressures used. Due to these nozzles being designed around aquarium pump usage, the orifice is larger than a high pressure system would use, and this lowers the ratio, but reduces head pressure against the pump. This enables a wider range of pumps to be used than normal eductors.
These are some pictures of the eductors that I used in my home reef tank. They cost me around $25 each (just for the nozzle, not including the loc-line), and they are only available in 2 sizes, both of which to large for small tanks and too small for giant tanks.
So, after looking at some other DIY eductor designs, I decided that my design would need to meet a few requirements.
First, the materials cost must be under $1.
Second, it must be compact.
Third, it must be able to be scaled up or down to work with any flow needs from nano to 1000 gallon monster.
Fourth, must require no special tools and only take a few minutes to build.
And most importantly, it must actually be functional! Many designs that I've seen will not be functional, and/or will be worse than no nozzle at all.
So, here we go.
The only materials are 3/4" sch40 PVC and 1" sch20 PVC. I bought a couple of 10ft sticks at home depot for about $4 for both 10' sticks. This makes the cost per eductor about $0.15 each.
Tools are a hacksaw, a burns-o-matic torch, a screwdriver handle, and an old lightbulb. Gloves will also be nice
To make the convergence nozzle, heat a 1" section of the 3/4" PVC pipe, pull to stretch it as far as possible without tearing it. If you are wanting to make very small orifices for higher pressure pumps, you can snug a zip-tie down on it while it's still hot.
To make the outer nozzle, I cut off a couple inch piece of the 1" PVC, heated it softly with the torch, jammed a screw driver handle in 1 end, and forced a light bulb in the other. After a little practice, this gave me just the shape I was looking for.
So, here we have some finished pieces for examples.
I tried a couple of designs for a part to hold the secondary apature. This was what I settled on because it was very quick, easy, required no additional materials, and blocks very little flow.
Here are bunch of finished nozzles. Notice that I'm making lots of different shapes and designs to try out what works best.
Here is how I made the holders. The pics explain it pretty well. Very simple to make.
Eductors are a very neat tool for our reefs. They enable a pump to circulate a small amount of water at a high pressure, and turn this pressure into velocity. This fast moving water stream creates a low pressure area, which draws much more water through the nozzle. Often they operate at a ratio between 4:1 to 15:1 depending on the pressures used. Due to these nozzles being designed around aquarium pump usage, the orifice is larger than a high pressure system would use, and this lowers the ratio, but reduces head pressure against the pump. This enables a wider range of pumps to be used than normal eductors.
These are some pictures of the eductors that I used in my home reef tank. They cost me around $25 each (just for the nozzle, not including the loc-line), and they are only available in 2 sizes, both of which to large for small tanks and too small for giant tanks.
So, after looking at some other DIY eductor designs, I decided that my design would need to meet a few requirements.
First, the materials cost must be under $1.
Second, it must be compact.
Third, it must be able to be scaled up or down to work with any flow needs from nano to 1000 gallon monster.
Fourth, must require no special tools and only take a few minutes to build.
And most importantly, it must actually be functional! Many designs that I've seen will not be functional, and/or will be worse than no nozzle at all.
So, here we go.
The only materials are 3/4" sch40 PVC and 1" sch20 PVC. I bought a couple of 10ft sticks at home depot for about $4 for both 10' sticks. This makes the cost per eductor about $0.15 each.
Tools are a hacksaw, a burns-o-matic torch, a screwdriver handle, and an old lightbulb. Gloves will also be nice
To make the convergence nozzle, heat a 1" section of the 3/4" PVC pipe, pull to stretch it as far as possible without tearing it. If you are wanting to make very small orifices for higher pressure pumps, you can snug a zip-tie down on it while it's still hot.
To make the outer nozzle, I cut off a couple inch piece of the 1" PVC, heated it softly with the torch, jammed a screw driver handle in 1 end, and forced a light bulb in the other. After a little practice, this gave me just the shape I was looking for.
So, here we have some finished pieces for examples.
I tried a couple of designs for a part to hold the secondary apature. This was what I settled on because it was very quick, easy, required no additional materials, and blocks very little flow.
Here are bunch of finished nozzles. Notice that I'm making lots of different shapes and designs to try out what works best.
Here is how I made the holders. The pics explain it pretty well. Very simple to make.
