You could probably control another brand dosing pump through coding. But I'd think it would be quite a complex set codes. With the DOS, the system knows the exact fractional ml that it doses. With another brand that doesn't have that level of resolution it would become a time to run setting based on the static amount dosed over a given period of time. Then you'd have to figure out how to adjust the timing to alter the dose for scaling within the +/- 15%. Not sure all of that is possible. I don't know of another doser that is Apex compatible which could offer down to the tenth of a ml resolution.
I will say that I will be monitoring it for some time before I hand over any dosing or pH control. Even then I think I'd want the limits tighter to start.
There are still multiple other safeguards that can be implemented as well. Within the output you can shut down it's function if things get out of line, with alerts sent simultaneously. pH too high or low, Alk getting too high are just a couple of those. I think part of the reason it's taking so long is this aspect, I believe.