I've only been keeping discus for 5 months. My tanks current set up is 4 months old.
Tank is L100cm x H50cm x D40cm. 200 Litres, 52 US Gallons.
Stocking: 6 juvenile discus, 30 cadinal tetra, 2 rummy nose, 4 oto cats, 5 cory, 1 electrc blue ram, 1 bristlenose, 4 amano shrimp (soon to be 20!!)
Water changing routine - basically, i have two other tanks. A 5 gallon planted low tech nano and a shallow 7 gallon blackwater. I take out about 5 litres of these a day and refill with water from the discus tank. I then refill the Discus tank. This means that i basically get a 5% change per day, and then on a sunday, i do a big 5% water change with water conditioner.
Filtration - i have a 1000l/hr canister filter with modified trays from manufacturer recommendations (my way has all foam in the bottom tray going from course to fine and two trays of crushed lava rock). Also, a 1800l/hr internal filter for flow and water polishing. I have this facing the glass to obstruct the flow speed but still get the faster filtration.
Soil/substrate - Under the sand capping (1 inch) is a mix of gravel and oliver knot aquasoil and tropica plant growth substrate on the base.
Dosing method: 30ml chelated trace elements.
co2 - I use a diy yeast/sugar method that fills two in tank reactors and lets the co2 slowly dissolve throughout the water over the photo period.
Lights - I have 2x T8 tubes and fitted a diy LED 20watt floodlight to the centre of the canopy. the T8's are on for about 17 hours and the LED floodlight for 10 hours. Some say thats way too much light...i have my fish to view them and enjoy them so i like the lights on. Fish seem absolutely fine with it as you can see and are never shy.
Tank progression in the photos, Pic 1 is day 1. 2 is 1 month, 3 is 2 months, 4 is 3 months, and 5 is now.