Gotta love China. I can get 4" for about 2.50 but 60cents sounds nice!
And yes algae control too. Thats the bitch about rockwool. I just use it as a starting media. But I think I'll try the caps on a 4x4 test site soon.
Yeah that's not a bad price. Managed to get the floralfex 6" caps for the same price off a wholesaler who had more then he could sell