Bottom Entry Fill Valve sizing?

[hoopster1975]

Our cistern is taking ages to fill, and we had a new syphon filter installed only a few months ago but I noticed since then that the plastic sheath (see-through thing) that hangs down the side of our bottom entry fill valve is leaking in several places and only a trickle of water comes out the top of the valve unless I push the float down a little and then the flow increases a little.
I have been looking at Fluidmaster but noticed that they either come in 1/2" or 3/4" and I dont know what one to get, please can you help in any way?

 

[kevplumb]

1/2""

 

[hoopster1975]

Thanks kevplumb for your prompt reply, I hope that the Fluidmaster valve is relatively hassle-free to fit, but at least I won't get the wrong one, thx again!

 

[muggles]

Get the Fluidmaster Pro, it's not much more money and has a brass shank (the threaded bit on the bottom you connect the water to). You'll find there's much less risk of stripping the thread and it'll be easier to attach successfully than one with a plastic shank.

Incidentally I've never seen a 3/4" one, they do 3/8" ones but they're rarely used in the UK, 1/2" is standard here

 

[hoopster1975]

Cheers Muggles, the Fluidmaster Pro was the one I had been looking at as it received pretty good reviews on Screwfix, just hoped that it would be ok for me to replace rather than our plumber as he is currently in the Dominican Republic ( I think we partly funded that for the last botched job that he did with our boiler and syphon in our toilet, he flooded the bathroom and had to re-fit the cistern twice with my help!) so I think I will do this one on my own.
Thx again.

 

[kevplumb]

well you know where to come if you get stuck