Doesn't the renew storm system handle the ATO? Also you may want to turn the strainer on the 20g tank up a little. If you lose power a lot of water will dump into your 40g tank. Looking at the 40 I see it isn't full so it may not over flood the tank.
Thanks yes i tested it when i set it up and removed the strainer and placed the reversed the elbow (facing up). This way it only drains a hair into the 40.
ATO is controlled by genesis. instead of plugging a pump to STORM (ATO) i put the solenoid. so when genesis detects low water in sump it sends power to ATO outlet which turns the solenoid on letting water through to sump. solenoid stays in closed position until powered.
this setup reduces multiple pumps (lots of heat and electric)in ro/di bin for each tank.