Backyard Aquaponics
A place to discuss aquaponics

G'day guys, new to this and looking for some advice please.
I'm building an in ground pond (4500 litres) with IBC's as gbd's and was wondering if 25mm pvc inlet pipe (19mm outlet hose) was too big or not ? also can anyone tell me what a reliable pump will cost in perth?
Cheers

Peter

By inlet pipe do you mean drain from the gbs? Outlet hose being hose from the pump?
I assume the cubes will be cut in half, so you'll have about 8 x 1/2cube beds? Pipe size depends on the amount of flow required. So if you're doing a slow drain, then small pipes may be ok. But if you want to do fast drain, then go with bigger pipes. I'd allow for both, so go with 32mm or 40mm. Bigger pipes also means less potential for blockage.

The outlet pipe, from the pump, will probably need to be bigger. But again it depends on the flow you require. Small pipes will put a lot of back pressure on the pump, and slow down your flow rate. If you plan on filling the beds slowly then use 25mm. If you plan on filling the beds fast, then use the 32mm pipe for the pump outlet, to give you maximum flow. Obviously filling fast will also require a larger pump

not sure of the price of pumps in Perth.

Base you pipe size coming from your pump, on the pump. If the pump has 25 mm fittings then the piping from your pump should be at least 25 mm or bigger because you don't want to hurt your pump.

You should size your pump to move at least the volume of your fish tank (a bit extra is usually a good idea) per hour at the height you require. (That is if your pump will be on all the time. If you will be using a timer, then figure the appropriate size pump to move the volume of your fish tank in the amount of time you plan to have the pump on.)

Gravity drain piping should always be larger than the pressurized pipe in your system. Exact sizes needed will depend on layout and design (like is only one bed draining to each drain line or are several beds feeding one drain line.) I have a 1 1/2" pipe from a pump feeding my fish tank which overflows by a 3" pipe out to my grow beds, the 3" pipe is only just big enough.

The size of stand pipes or siphons is going to depend on the flow rate into each individual bed. For timer operated systems with stand pipes, the actual stand pipe can be quite large, the flow rate out is controlled by the size/# of the holes near the bottom of the pipe. The actual stand pipe being fairly large is a good thing so it can act as an overflow when the water level in the bed reaches the desired flood height.

thanks guys, great advice
it's given me more to think about

i'll let you know how things turn out in due course (with photos attached)

cheers

peter

Always go bigger than needed, you can throttle back the pressure line with gate valves and there is no point in limiting your system with such a small cost saving!

+1 on bigger is better.
Always over-engineer your pipe diameters.