anyone used these knife style gate valves
 

heres the gate valves i picked up today... im trying to find something to replace my ball valves because they are very stiff in and inacurate.

http://www.pondparts.com/images/categories/C251.jpg

i got a great deal on these today and i think they will be allot easyer to use, just wondering if anyone has experience with them

thanks
craig

Had them on my hot tub...worked fine.....

Metal parts? Just noticing the screws on the outside of the valve. Are there any metal parts inside the valve? If so I wouldnt use them in a salty application.

I use one as a gate valve mod on a Euroreef (not submerged), it works fine but the rod to the handle will rust a bit.

You make two points here...one is that your ball valves are stiff (lack of use...? or lower in quality...) and the other is that they are inaccurate.

Ball valves are Not really chosen to be accurate in terms of their ability to control flow. They are best for on/off application. If you have a need adjust flow with some accuracy, then a gate valve is the best option. You want a gate valve like these:

http://www.customaquatic.com/customa...dexid=pf-gv-so

I don't know what the best application for a knife valve is supposed to be. They are not commonly used in aquariums for sure. They certainly don't look like they would be particularly accurate to adjust.

knife gate valves are for on off only not to restrict flow, its hard on the valve and it wont stay in place for very long the increased pressure on the valve will cause it to open more

They rust in saltwater application. I speak from personal experience.