"lee" wrote in message
...
Thanks for your replies. The filter gets full sun and the flow rate is 500
gallons an hour. The filter is 12 inches deep and this is the second
season
of poor growth.

Drop off the Key Lee, get yourself free
I would say theres to much flow, 500 gallons an hour sounds hefty, any
chance of teeing off your flow so that flow is reduced somwhat?
--
**So long, and thanks for all the fish!**