I run a separate air pump for stones. I bought pump (100 gal. model) and stones at Pets Depot. Pump - $29.99, Stones - $4.99 ea.

Yup, after I cut and treat clones I place in Rapid rooters and into coco. I built my own cloner w/2 bus pans 4 & 6 in depths, w/small pond pump in bottom of 6 in w/nutes, bought 1/2 in. pvc to bring water to top, more pvc to build square (ring) w/holes and timer is set for 15 min every 6 hours.

Hope this helps

Peace, PIF