Cheap dosing pumps

[AlexMontambeault]

While I don't necessarily need a dosing pump for an aquarium, I believe that they could work for my applications.
Basically, I have what is called a bioreactor. It is a small beaker where a mixture gets fermented.
This bioreactor requires some sort of Ph Control. I've got some Ph Probes with a BNC connection.
Basically, what I would require is some sort of Dosing pump that can be connected to a computer or something, so it can receive inputs from my ph probes to start injecting some ph liquids.

Is there any cheap dosing pump able to do this? I can't be manually giving the injections nor can I schedule them.

Thanks for your help;Alex.

 

[coil1002]

How many pumps you need? And how would you be controlling them ? You have ph probes but what controller are they connected too? Just a ph monitor ? Are you trying to keep ph high or low ? In other words the solution your dosing is it raising or lowering ph ?

 

[AlexMontambeault]

I either need single, double or 4 dosing pump machines(preferably doubles), in total I have around 15 units which all require 2 pumps.
The bioreactors need to keep the ph stable, so there is both a solution raising the ph and another that can lower it(hence why 2 pumps/units are needed)
the ph controller has a BNC connector, so I could connect it to some sort of cheap computer(Which I'll buy for this sole purpose)
This computer will also be connected to a bunch of temperature sensors and start some heat elements(but that's not really related to my Ph problem)
The pumps would be controlled by a program. When the solution Ph is too far from the desired level, It would either inject Ph+ or Ph- and wait a little bit. High precision is not all too important because the ph solutions can be diluted.
I don't need any monitoring on the pump(as in, how much did it inject)