Considering ATO

[cwatkins]

+1 on the Tunze with the optical sensor. Hasn't failed me yet!

Well the little pump motor did burn out on me just recently, but I get lazy and forget to refill my reservoir on time, so the pump often runs dry. It's smart enough to turn the pump off after a bit, but I guess I let it happen too often. Opps!

[sphelps]

Originally Posted by molotov

I completely agree that salt creep would be enough to keep a manual float from closing. I also think salt creep could also cause a float switch to fail as well.

For redundancy using a mechanical float switch, I would position one mechanical float slightly higher than the main float. Should the main float ever fail, the higher float would cut water to the failed float. My thinking could be flawed but I've read quite a few reviews on BRS and people swear by them. I am new to this and definetly no pro so anyways those are just my thoughts.

Yes but with electronic you have options.
1. You can connect multiple floats in series by simply wiring them in series and placing one slightly higher than the next. They are also small enough to fit pretty much as many as you feel comfortable.
2. You can use a timer to control how long the ATO is allowed to activate for each day and how often.
3. You can connect multiple pumps or solenoid valves as well.
4. You can even wire in some kind of alarm to alert of whatever kind of failure.

With manual you don't have any of those options. You'll have to explain how to connect two manual floats together in series. I've never seen a manual float that can be connected that way. While you may view the manual float as one part and simple that doesn't mean reliable. One part means one part to fail, with electronic many parts have to fail at the same time for an error to occur and how many parts is up to you.