Tank Automation - Float or Resistance Sensors

[CTSap4Maple]

I'm looking to automate my collection tank to pump down when full to my shack storage tanks. I found a pump down control relay, National Controls Corp. Model NS139, that will activate the pump at the high sensor, shut off at the low sensor and repeat. It uses resistance probes rather that float switches. Are resistance probes preferable to float switches, and will resistance work in sap? I have a non-conductive tank so will need to use a common probe. Thanks in advance!

[DaveB]

I can't speak to which is preferable but I use a float switch in my feed tank that kick off a pump in my main tank to fill it. I manually do that for a tank that I have in the woods back to my main tank but I am looking to automate that as well and was going to use a float switch for that operation.

[lew]

Sap is conductive, conductive enough for these sensors though, I do not know. However, a simple sump pump switch works wonders. And they are dirt cheap and reliable.

[BreezyHill]

I'm looking to automate my collection tank to pump down when full to my shack storage tanks. I found a pump down control relay, National Controls Corp. Model NS139, that will activate the pump at the high sensor, shut off at the low sensor and repeat. It uses resistance probes rather that float switches. Are resistance probes preferable to float switches, and will resistance work in sap? I have a non-conductive tank so will need to use a common probe. Thanks in advance!

Sap is a very poor conductor...I use a glass milk system releaser and had to use a float switch since the standard tri pole dairy probe was unable to conduct enough elec to trip the relay. I even bumped up the volts and still could not get the volts to trip the relay. Increased the surface area with a winding that was only 1/16" of separation on 4' of wire and still not enough volts.

Stainless steel floats are best and easiest to clean. Bacteria will cause issues with the floats operation when it gets dirty enough. I use hydrogen peroxide in a tank sprayer to clean off and out tanks and rinse with water or sap depending on what you have available.

Ebay has some very good duel float switches that will work for your need in several different stem lengths.

Good Luck!

Ben

[CTSap4Maple]

Thanks to all. I found an inexpensive stainless dual float and controller on eBay. Should work better than probes.