I just use flocor since it cannot pack down under its own weight unlike alfagrog or ceramic media.
The water needs to trickle down over the media but you can have 10 trickles or 100 trickles which is ten times the flow rate, it simply depends how wide the TT is. I pump 705 gallons an hour through a TT 18 inches wide and it works well.
Alan F
Posted on May 14, 2006, 5:43 PM from IP address 213.120.101.21