Thread: 110mm ball valve V slide valve?

I take the view that if you have a valve closed and only occasionally need to open it slide valves are good, if a valve is normally open and only occasionally closed go for a ball valve

The only time I have used slide valves is on my grow on tank. One (before a sieve filter) remains open all the time and one (on the waste exit of the sieve) remains closed all the time.

Both leak like a sieve when closed, excuse the pun :-).

Whereas I have used only ball valves on my pond and also a ball valve on the bottom drain purge line on my grow on tank. None of them leak.

So personally I think your right to opt for ball valves over slide valves. From dealing with two leaky slide valves, if I ever build another pond I don't think I'd even consider slide valves as in my experience, they are pants!



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In terms of valves, I've tended to get them from coastal koi.

I did buy a cheap 2" ball valve off eBay once for my grow on tank purge line. But, although it doesn't leak, it sticks in place and is really hard to open. So I personally think it's best to fork out for a decent one.

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I hate my slide valves, they leak if you use them. I would swap them for ball valves if I could fit them in
I just can't.

Originally Posted by deeper blue

Thanks for the replies, Benjamin I live in Guernsey but thank you very much for you kind offer.
I have not done a huge amount of research but another factor seems to be…. ball valves have unions each end so can be removed, or one section of pipe can be removed with the valve in place.
It is a difficult call because both valves have their merits.
I have been asked to sort out a large pond of approx 7,0000 gal, it has an existing filter system that was fitted around 7 years go but not maintained.
Unfortunately the builder did not fit and isolation valves to the filter so I have to drain the pond to fit some valves.
IMG_0446.jpg

This true and, in 30+ years in the swimming pool trade, I've done it more times than I can remember but be careful if you remove the outlet side of the valve, (the pointy end of the flow arrow), because that's the side that holds the ball in place so the water pressure on the inlet side of the valve could push the ball out.

The kind of pressures used in pond installations aren't very great so this isn't very likely but I always have a strong rubber band ready to slip over the exposed side and wrap around the handle ready to prevent that happening anyway.