I feel that a pump would be very hard to control volume. That is what a doser makes easier.
I have my reactor fed by DŌS. It feeds in 2 liter of tank water and pumps out 2 liters of kalkwasser in a day. I added advanced programming to the DŌS as follows for both the input and output:
Code:
If OUTPUT DOSEKALK = OFF Then OFF
I created a virtual outlet name [DOSEKALK] defined as follows:
Code:
Set OFF
If pH < 8.28 Then ON
If pH > 8.30 Then OFF
If Alkx7 > 9.50 Then OFF
If Output MAINTENANCE = ON Then OFF
If Output FEEDTIME = ON Then OFF
Used together, the DŌS doses on a schedule, but is limited by a few metrics or modes.
You can adapt this to work with a pump, but it will be tricky to get precise dosage.