Peristaltic pumps are the choice for two reasons, one there is no mechanical contact with the liquid and two they’re very precise. There are a couple dosers on the aquarium market that can dose down to .01mL (that one uses stepper motors).
The problem with most of the units on the market is, they’re either incredibly expensive and don’t meet the needs of the average reefer (reefer is a hobbyist who grows and maintains a coral reef tank…nothing to do with smoking ), or they are kind of expensive, $250+ and use cheap pumps with poor programming methods. On the expensive side, one of the dosers is $350 and it only has two pump heads, the other is $500 and only has three. Most tanks need four or more pumps. My goal is to give reefers a resource list of products to give them the options of at least four pumps, they can choose their own pumps to meet both their liquid requirements as well as keep it within financial reach.
Most of the hobbyists are all about DIY and love projects, so I think people will enjoy this project, and people will buy photon boards too!