Welcome, Josh! Agreed with Steve, this is a great little invention.
I'm not sure the second "holding tank" is really all that necessary . . . . the ratio of volume lost due to lower levels is quite small, especially if you have lots of coils in the bottom! you could have as many coils as you wanted, just make a less potent solution. . . .
Also, it seems that an airline gang valve may be really useful to adjust he amount of pressure when dosing: http://www.aquaticeco.com/index.cfm/.../9904/cid/2348
I really hope to see this idea catch on, I just love the concept of using the air pump rather than a powerhead or submersable!
PS do you have a picture of the prototype?