I agree with Cali It stinks dosing, I forget sometimes myself, and there's the days I run out, and its another week before I dose, I stopped that right away bought a calander and when the day comes when I have to dose, I check it off, As a matter of fact I write down everything I do in the calander,I use to use aquanote's and a couple of other programs, there great but it a hasle more time, and when i restored my computer I lost all my info, wasnt to happy, But back to the reactor I Heard good thing about the k2r and koralin, Just make sure you buy one that will handle the load of your tank fully stocked, bigger is better, smaller and youll end up dose along with the reactor.. I just set a my boys new Deltec Reactor, Real nice , ph prode holder in side , cream of the crop ....if you got some extra money look into the deltec..I have a 55 gallon , I dose,but if i had anything over 100 gallons I would buy the reactor, simply because it ends up being cheaper than dosing, chemicals end up costing alot for me about 25 bucks a months..Good Luck