Backyard Aquaponics
A place to discuss aquaponics

Sorry if this somewhat on topic.... but advice please..

Have an "Electromagnetic Air pump "... It has a 10mm outlet .... specs as below...

Output: 60L/min
Power: 35W
Pressure: 0.03Mpa

I want to run this through PVC pipe, which will be tapped with adjustable outlets...

Questions....

What sized pipe would I be best using... and why?

What's the maximum length I might be restricted to, and what's the affect of length (if any) on pressure over distance?

Thanks.

For 60 litres per minute - anything over 10mm will be fine. The distance wont make a huge difference - its a very small amount of air, so friction losses are minimal.

Main thing is to eliminate leaks.

Hi Rupe
I have a pump with almost the same specs
25ft of 6mm bore tube with 2.5cfm flow may lose upto 600mm wc. With 0.03mpa being 3000mm and assuming a safe max operating pressure of 2000mm..the pipe just cost you almost 30% of your output pressure with no benefit to the fish
Higher flowrates (regen blowers) will incurr larger losses as do tee`s, elbows and taps.

Get a 100ft hosepipe and blow down it, then do the same thing with 20ft of 4mm airline..make sure someone is there to catch you when you flake out
A ring manifold of 40mm pipe will have minimal loss and the pressure is uniform. Tap off short lengths of smaller bore pipe to the airstones.

40mm is waaaaaaaaaaaaaay over doing it. 6mm from a 35 watt pump is just silly as well.

25mm at the most.

$15 per length instead of $40 or whatever it is.

Thanks guys... was thinking of either 15mm or 25mm pipe... coz that's what I've got lots of...

Outlets are "tapped" in... and can be adjusted for flow... like these...



Air lines run off the taps to air stones...

So Hex... you're suggesting that 25mm would be the better option??

And what exactly do you mean by "A ring manifold"...

T - piece from the pump outlet, pipe runs all around the circuit, and back to the t-piece. Connected at both ends of the pipe to the t-piece.

lol picture here

now that, Ozzie, is what I call interesting first hand information
we should gather forces and try to find out what could be the reason of this as it seems contradictory

do you have pictures of both setups?

frank

Figured that's what was meant... but have to confess a lack of knowledge as to why? ... is that just to maintain pressure ....

Had hoped... just for reasons of layout to tee off to two seperate runs and just end cap them... no good, can't do??

Hi Obo
Your right but if you want as much of the air making it to the tank its not much extra effort. I guess it mainly depends how far the pipe runs have to be and number of airstones.
40mm pipe forming a distribution ring is the way most aquarium shops install central air. The distribution ring itself has virtually no pipe losses so each tap point on the ring is pretty much at the same pressure as the pumps outlet.
The main losses are from the airtaps, the short small bore lines and airstones themselves.
Multiple longish runs of pipe from the (usually naff quality) straight manifolds supplied with airpumps will rob pressure that could be used in the tank.

Oh yes, most definately not the 6mm from the plastic supplied manifold.

If you can join the 2 runs back together rupe, it will be the very most efficient that it can be.

To be honest, two runs of 25mm (for that amount of air flow) will be exactly the same pressure at the pump outlet, as at the end of the run.

personally, I think that the 15mm will be more than enough - especially if ring mained.

Frank, spraybar below: did not get a picture of the aeration from the weeper hose yet.



It runs for the full 6 metre length of the fish tank. I just kept drilling holes in it until there was an even flow rate across the length.

Remember, I was on the airpump hater brigade as well, before I got the new proper air pump. I am now converted.

Rupe
Use the pipe you have on hand to make the ring, theres no sense in buying new stuff if you have some that`ll do the job. Whatever size it is, it`ll definitely be better than fitting seperate longish airlines to the basic 10way straight manifold located at the pump.
Don`t forget to use a check valve or locate the pump above the tank.

Again, thanks guys... no way I was going to run multiple lines from the outlet manifold...

Pump will be above the tank Hex...

I am not an airpump hater, Ozzie
hate blinds and is just a waste of time

I would love to use airpumps if they were efficient as they have a lot of advantages.

to comment on the picture of your spraying bar:
seeing the jets on this bar suggest that some pressure is built up in the pipe (to prove this, just cut off the end of the pipe and no jets will come out of the pipe, only trickles)

it seems controversial, as to the eye, injecting water into another volume of water seems to inject air too
and the bubbles seem to confirm this, but that is limiting aeration more than it is enhancing it (my opinion)

so I question that (which is not the same as contradict): pressure buildup is always detrimental to volume pumped
volume pumped is essential to water/air surface exposure

also in your system there is no room for passive aeration, as the pump exit leads to a closed pipe and no air/water contact is present
leading your pump exit to a wide pressureless gutter instead of a narrow pressurized pipe will easily decuple surface contact area
making the water flow in that gutter turbulent instead of laminar will exponentially raise contact surfaces

all for free, since gravity is your pump once the water is pumped to gutter height
all that is without flowforms or high gain passive oyygenators

give your pump a chance

frank