Water Change Programming Help

[sphelps]

I have one level sensor in the mix which is in the sump and controls the top off. When sump level drops the tank is topped off with saturated salt water or fresh water dependent upon tank salinity.

I have 2 main solenoids connected to a constant supply of RO water. One solenoid simply supplies fresh water to the sump the other sends fresh water to an inline 30 gallon tank which is full of saturated saltwater. The 30 gallon tank has an overflow in it and as fresh water enters one side of the tank, saturated salt water overflows from the other side which is then sent to the sump (gravity feed).

The system changes a small amount of water daily rather than larger amounts less often. This prevents large amounts of saturated salt water from introduced into the system. If tank salinity gets too high or low the water change system is disabled until salinity returns to normal range.

I've also installed a third solenoid valve inline and before both main solenoids. This is a safety solenoid which activates with either main valve and will prevent disaster if one solenoid valve some how manages to fail in on position (highly unlikely).

So far the system is working very well, completely automatic. All you have to do is add salt to the 30 gallon tank every couple months. It will hold 150 gallons worth of salt and the controller sets an alarm when the salt supply is low so even if you forget you will get reminded and the system will not continue to change water unless salt is added.