I picked up a JBJ Ato last week with the intent of automating my water change. I run this tank bare bottom so it collects detritus in under 1 of the rocks which is less than ideal but honestly not more than 3 minutes of maintenance. The implementation of this stumped me for a while today. This is only the second time I've used my programmable timer to do anything complicated. I need to make three separate programs for different scenarios during each one the behavior of the main return pump has to be different or I risk a run-dry scenario until I switch to a higher volume AWC pump (aqualifter currently is very slow and methodical) I can only do smaller than 3 gallon changes.
1. Remove detritus (<3 gallons)
2. Small water change (5-10 gallons)
3. Large change (>10 gallons)
Program 1
The program starts by pausing for 15 minutes then turns off the main return pump, osmolator, and skimmer venturi pump for 45 minutes. The water change starts by having the aqualifter pump located in the saltwater reservoir pump attached to the JBJ ATO (the timer cycles the ato every 10 minutes to keep it pumping). As a safety precaution the main return pump cycles for 5 minutes as 20s on 40s off then returns to the on state for the remainder of the water change period (as long as the water change is <3 gallons the pump remains submerged). The saltwater top off turns off, while the return pump, skimmer, and freshwater ato turns on at the conclusion of the 60 minutes.