I use a really cheap sub....you might try it. I make a 50:50 blend of 300 grit sand and fast orange....add 1/4 cup of water and blend. Some people add ice when it's warm out or sub Coca Cola for the water...but I don't know if I'd go that far.

I comes up to about $12/gallon. It's like SLICK50 for your Optimax.

That baby will pur like never before.