So my big display tank has a system capacity of just under 800 gallons of water. Over the weekend I finally got installed the new FMM module for Neptune's Apex System which controls my tank. I added this module to handle the automatic top off function on my tank so that every night I do not have to go to the basement to make sure the tank is topped off after the days evaporation. It was a breeze to set up although I did have to order an additional extension power cable for the pump to be able to reach my holding tanks which are located in the basement in my laundry room. I have two 65 gallon tanks, one for RO/DI water and one for made up salt water.
I have a pump the runs continuously to stir the made up salt water tank, taking water out of the bottom of the tank, then adding it back in via a line to the top. The water line extends half way down the tank with an eductor aimed along the outside edge pointing down so I get a mixing action with the flow of water constantly stirring the tank (great when adding salt).
I added a pipe fitting to the top of the RO/DI holding tank so that the power line to the pump and the water line for the top off valve could easily flow out. You may notice at the rear of the tank is the RO/DI water inlet.
Power connections and the brains of the operation are the FMM module which starts the pump when an optical sensor in the top off module reads no water, then shuts the pump off when another optical sensor reads water level is optimal.
Here is the sensors and top off assembly installed in the sump. With several days operation now, this is amazing as it keeps water levels perfect without any effort on my part but to insure that all is well. You will note that the float switch is a back up for the optical sensors and prevents the system from adding too much water.