Really, the BRS 2-part is about as easy as it gets IMO. If it's a small tank and/or there is minimal consumption of the Ca and Alk, then manual dosing can easily take care of it for you.
If it is a larger or more demanding system, then there are countless dosing pumps available. Some are easy to set up, some are written in engrish. Some are (almost) prohibitively expensive, others not so much.
I use a pair of BRS 1.1ml dosing pumps and digital lamp timers for both my DT and FT and find them very reliable and easy to adjust.