My tank is a 5ft 470 ltr heavily planted tank running pressurised Co2. It has a plant medium under natural river sand and I'm using EI Ferts, I think you will agree the plants are looking fine. There isnt a single spore of algae anywhere in the tank.
You can get a better idea from the video taken just over a month ago.....
http://www.youtube.com/watch?v=LnD0HuY_K9c
It has 3x 1500lph external filters, (2 are linked together) with an intake at each end of the tank and one long spraybar for the return. There is an inline Co2 diffuser in the outflow hose from the double externals and UV Steriliser running from the other external. there is also a Juwel Internal filter which I ripped from a Juwel Trigon tank and siliconed it in the this one, it has a 1000lph power head on it. It helps with a circulation flow and a small power head at the opposite end of the tank ensures the Co2 is well circulated round the tank.
Contrary to what some thing the Discus are absolutely fine with the flow. They are all large Discus, between 7 and 9 inches tall. There is now 12 in the tank.