Backyard Aquaponics
A place to discuss aquaponics

Despite using 25mm poly for my overflow, the 19mm inflow into my tub is still too fast for it to cope. I've thought about maybe using 40mm or 50mm PVC instead for the overflow (surely this would cope!).

Currently I'm using 25mm taps to control the flow to each grow bed. The thing is, I don't know how to connect these taps to the PVC (without using a drill and silicon like OBO has done in the past). Does anyone know if connectors for 40mm or 50mm PVC to 25mm poly exist?

Kinda. 40mm pvc-to-threaded male end, then poly female thread-to-what ever they call that bit you push the poly over. There might be one fitting but to find it, and if the local hardware stocks it. I'd just use 2 fittings.

+1
I have seen a 25mm barb to 50mm PVC in bunnings, but the barb is of crap quality and doesn't hang on unless hose clamped (metal screw hose clamp, not plastic clip lock)
Have a look, they use them for diverting drain water into 25mm hose for dumping on the garden.

Thanks guys - I'll check it out tomorrow.

Oh yeah, and the fittings you need are:
1x 50mm PVC to 2" BSP female ~ $2
1x 50mm to 25mm threaded adapter (2" BSP male to 1" BSP Female) ~ $2
1x 25mm directer (1" BSP male to 25mm hose barb) ~ $0.90

or

1x crappy bunnings fitting = $7.00

They priced it so it was about the same cost. I'd get the three fittings. Make sure they don't charge you regular retail.
Stay away from Reece, Bunnings, and other big places, as they will sting you full retail every time.
Go in to a small store knowing what you want (names as above) and sounding like you know your business, then ask for the best price.

And having an ABN and 2 business names helps.

I only have 2 Christian names, no business names, yet get trade discounts at 3 local industrial stores.

Do you get your GST back.

Pay cash... don't pay GST (Sometimes)

I'm confused. It seems to me you were saying the drain plumbing was not able to keep up with your inflow plumbing. But then you seem to be asking how to make the taps fit if you replace the inflow plumbing with larger pvc?

Seems to me you would leave the inflow plumbing with the taps alone and install larger pvc drain plumbing.
I must be missing something here. Are the taps on the drain side of the set up?

Now that I read the thread correctly I agree.
25mm taps to control flow suggests you have them on the inflow, but you say your inflow is 19mm.
Your overflow is 25mm, if you want this to be bigger, then remove the 25mm altogether.
any 25 mm in your overflow will restrict it, 50mm all the way for drains. This is how I build it now.
Sometimes 50mm is not enough.

Apologies for the confusion. I'll try and be clearer.

I have a tub on the back deck that I plan to use as a water feature. I'm currently pumping directly into this tub from the sump downstairs using 19mm poly, and the tub overflows into the 4 GBs on the back deck via 25mm poly. There is a tap for each GB to regulate flow. These GBs then drain back to the downstairs FT then back into the original sump. Then the cycle starts again...

The 25mm poly overflow from the tub currently can't cope, so I plan to change this to bigger PVC, but I would like to keep using the 25mm poly taps.

So, in summary, I need to connect 25mm poly taps to 40mm or 50mm PVC.

I use 40mil for supply and use 40mil tees at each grow bed. (Some pictures on page one in the link below. No closeups but you should get the idea).

If your 25 mil taps are unthreaded you can use a 40/25 reducer and a small piece of 25 mil pipe to step down.

If the taps are threaded then you can still use the reducer and small length of pipe but you will also need a female to male threaded joiner.

Take you taps along to the B store or local plumber and you should sort it out.

Well, I arrived home tonight to find the tub overflowing (even though I thought I had temporarily fixed it by slowing the flow).

In a state of half-panic, I'm not proud to say I went to B to find a solution. In the end, I went home with:

• 1 x 3m length of 50mm PVC
• 3 x 50mm Tees
• 3 x 50mm 90 degree bends
• 1 x 1.5" BSP adapter to 40mm adapter
• 1 x 50mm to 40mm reducer
• 4 x those 50mm to 25mm barb reducers.

This allowed me to use my existing 25mm poly taps.

Even though I know I paid too much, the end result sees the tub no longer able to overflow (even at maximum pressure). It actually looks quite neat also, even if I do say so myself. All I need to do it give it a coat of paint when I replace my dodgy railings.

I'll post some photos on the weekend to my system thread.

Now, I'm open to constructive criticism... so let me have it!

You'd be suprised at the mix of fittings I've used. Connecting lowpressure to high pressure to extender pipes for pop up sprinklers. Just sux that you guys have big hardware stores so close.