15 to 30 cm. per second for optimal bottom cleaning.
Measured where?
We are talking about a radius here dealing with velocity?
I mean, where do you pinpoint this at?
Come on, this is a DIY thread and those numbers don't mean anything without nailing down specifics like at least where you measure this velocity at, and doubt many would buy a book that has crazy math in it.
This will all change quite a bit depending on tank diameter and water depth, so some insight would be nice on a DIY rig.
I mentioned that I may have a few questions.
