So I built my own RDWC system from scratch, modeled after current cultures undercurrent system, it works like a dream! So easy to maintain and growth rates are absolutely massive. You mentioned you don't have a hardware store around you that sells the parts, but really everything you need can be found online. I assume you don't have a lowe's or home depot near you? The uniseals are the hardest thing to find, but most aquarium suppliers carry them. If you can manage to scrounge all the pieces you need, building one yourself is hands down the way to go. I built my 4 site 1 control system for around $350, all in, pumps, tubes, uniseals, everything. The same system if purchased from current culture will run you $1,000+. Anyway, just some food for thought, but I highly recommend going this route if you're planning a RDWC.