Backyard Aquaponics
A place to discuss aquaponics

25mm PVC ball valves vs 25 mm LD Poly valve

I was looking at the two of these in a 'plumbing shop' the other day and noticed that the valve ID due to the valve construction was almost identical in size (poly valve may have been 1mm larger).

Given that the poly valves are under half the price of the pvc ones, are there any obvious reasons NOT to use poly valves (or poly pipe as well for that mater) in a system?

Advantages of poly:
1. cheaper,
2. UV resistant (pvc ball valve specs I looked at specifically said non UV stabilized)
3. easily re-usable (though so are pvc ones if get threaded type)
4. if using poly piping can use gentle curves rather than PVC elbows that reduce efficiency

Disadvantages:
1. potential failure if using plastic clips to secure, though I am using them with 'wire twists' in my system at present and they will not budge - even with the wire removed I have to cut the poly to get the valve off if its been installed for a while.

What am I missing? It seems most people use 25mm PVC pressure on the supply side

Nothing wrong with using poly.... just don't go smaller than 25mm...

another fail point of poly is if you have it running in the sun on a F&D cycle, watch out it doesnt get hot enough to burst when your pump turns back on, on those 42 degree days.
This happens easily.