The Fluvals I have heard are very good filters but I would encourage you to also check out the Eheim 2250 and 2260 models and compare prices/quality etc...I would also recommend you buy two external canister filters and run 2 x 300 watt Hydor ETH Heaters and a CO2 reactor inline. The reason for two is for ease of care of the tank and it's good to have a back up. Also when your cleaning out one filter you can leave the other running for your sensitive discus. I know you mentioned low tech so CO2 might not be necessary, but if it is there's another list of equipment to get. Your also going to want to buy dry fertilizers and not the liquid form because on a tank of that size liquid form will cost a lot. Also, what are your lights? Your going to need timers, testing supplies, and as far as your substrate is concerned, it depends on how much your willing to spend and your plant needs. It also depends on how much your willing to work in order to save money for example you could make Mineralized Topsoil and cap it with about an inch and a half of sand. Or you could buy ADA amazonia which will soften your water and is generally considered to be among the best substrates money can buy. A 9 liter bag is $28 which is actually not bad IMO. There's some other decisions you could make about how badly you want an equipment free look. You can get glass ware to replace the stock plastic outflow and inflows of your filters. You build a light hanging setup so that your lights aren't sitting on the rim of the tank. Also, looking around for some good pieces of hardscape is important either rocks or driftwood etc...