So the only issue I would have with your setup is this. It looks like your injecting peroxide after the pressure tank and into your contact tank. Unless you have a more complicated system and it's not just turning your peroxide pump on and off, you will have inconsistent peroxide amounts. You showed an outlet that goes on when there is water flow, but the water flowing could be 1gpm with a toilet, or 5gpm with a bathtub. But if the peroxide pump is turning on and off, it's injecting the same amount regardless of the water flow based on the dial set on the pump. There is equipment that measures the water flow and adjusts the pump settings based on that, but not sure if you have that or not. That's why I chose to put mine before the pressure tank. I calculated my well pumps 18gpm into the pressure tank when it turns on and refills the tank. That amount is pretty constant because its injecting at the same rate the pressure tank is refilling. I have 4ppm iron and very little magnesium and the calculations came out that I will only use about 2 gallons of peroxide a year but we only go through about 30,000 gallons of water a year at the vacation home. So not much at all. You will notice that the peroxide pump isn't running constantly when it's set. Mine cycles on and off while the pump is refilling the tank to get the residual value I want. When the calculator spits out the gallons of peroxide you use per day, you have to remember that's only when water is used. It's not being used 24 hours. So for me my well pump runs for 75 seconds when injecting peroxide and has a 20gallon drawdown. So I had to calculate how many times the 20 gallons will get used in a day, and how much peroxide it will consume.