Lime with lava rock

[Mrmilbourn1980]

I use lava rock and I love it. I have been doing a little more research and I seen that people use slow-release dolomite lime. My question is how much to use. A big portion my orchid collection stays outside in the summer time and gets fertilize weakly once or twice a week. They receive a lot of rain. I pretty much flush every time I water that I don't fertilize. I just recently started giving them Epsom salts for magnesium. Should I give them lime.