Opengarage sleep

I would like to put the opengarage to sleep to save power.

I have an opengarage and am very happy with it. I want to take the work further and make one up to monitor water levels in a water tank.

So far I have a nodeMCU programmed and a waterproof ultrasonic sensor. Thats all working great. I want this to be solar powered though, just using a solar garden light. So ideally run this thing only from a single AA battery that is recharged by the solar panel.

Im good with the electronics, I will work all that out, but I need help with the firmware and putting opengarage to sleep in order to save power.

My idea is to wake up every half hour or hour, take a reading and transmit it to blynk, then go back to sleep.

To go to sleep for half an hour, I use the code ESP.deepSleep(18e8);

My problem is, I dont know where to put that code, so it will sleep without breaking the operation.

I tried putting it in the main loop wrapper in the loop after the tcpCleanup, but that didnt work. Any ideas? Is it even possible just to slip this code in or would I need some major changes?