Brass is it safe ??
 

is brass safe for use in a salt water system I hate how stiff the plastic ball valves are to trun it is hard on the plumbing the brass ones turn nice and smooth make fine adjustments easy but is it safe for the fish and corals

Nope,
The only metal you might even want to risk would be stainless steel.
Even then you'd want surgical grade.

Yeah, definitely NOT reef safe. Brass usually contains copper, to my knowledge.

Definitely not. And it wouldn't last long anyhow.

If it's adjustments you're looking for, try looking at a gate valve. If you find you need to close the valve often (but are just opening and closing it) then try looking at a knife valve.

Some ball valves turn easier than others.. maybe try a different supplier if the ones you're using are really bad.