I have been using the BRS dosing pumps for years and like them. With a small system like that you could just figure out your rate of consumption for soda ash, calcium and mix it manually in Gatorade bottles or something and add daily or so while monitoring. I did this for a while with my 180 while the corals were getting established. Your corals look great by the way, nice setup. I think we underestimate the amount of Ca/DKH that healthy growing LPS, especially euphyllia use.