With a sump overflow is key; is this a drilled tank or HOB Overflow?
HOB Overflows have a tendency to fail just a note
Floats are of course optional. You will need a controller though which I use Apex with the FMM module
Example I have 5 Floats in my system all optical
Optical are best but you can do manual floats as well
High Float -- tells me something is wrong either my ato is stuck or something else and alarms me
Low Float -- triggers my ato to turn on -- my ato also has max time it goes on so it dont overflow my sump
Return Float -- triggers my return pump off which either my ato is too low
Emergency Float which is where my overflow is If tank water goes over a certain area triggers an alarm an shuts off my pumps.
I also have an Ato float in my Ato reservoir to tell me my reservoir needs to be refilled and not to turn on my pump if its too low.
Again all this is done through controller.
This is optical float Apex
https://www.bulkreefsupply.com/os-1...a-mNzspKMsGmJVjTdU0ub_K-OeztZgBBoC8IIQAvD_BwE
Manual float which you can do with a breakout Box Apex for example
https://www.ebay.com/itm/Top-Mini-T...064706?hash=item261ef400c2:g:7SoAAOSwNpNa4uKp
I also recommend leak sensors never can you be to careful. You're dealing with lots of water and if not careful will get a water damage. Especially if you're using a HOB overflow