Controlling for a doser malfunction

[g0rilla]

Have 2 gallons of calcium, alk and mag in seperate dosing containers hooked up to a ghl dosing everyday

lets say pump 2 (alk) decides to get stuck on and starts pumping alk uncontrollably into the tank

how can you protect your tank from a failure like this?
what safeguards can I implement (I have a neptune)

I have seen it happen to others and want to know how would you protect your tank from a doser failure

 

[swk]

I believe you can set something up if your ph exceeds a certain level you can turn the dosing pumps off.

Another way may be to use a float switch set up high in the sump. If an extra gallon of liquid gets pumped into the system it'll activate a float switch that will kill the dosing pumps?