He could use two float switches :-)

I use valves and control the drip rate rather than float
switches, but if I were to use a float switch, I would
tend to lean to a nonmechanical because in reef tanks,
there's a lot of growth that likes to get in to things.
But a nonmechanical switch could be less reliable than a
mechanical - depends on the design.

Also anyone looking at the possible errors of such things
should always look at the worst case senerio. Like will it
stick on, or stick off, how many gallons will go in, and such.

Wayne Sallee
Wayne's Pets



Pszemol wrote on 8/13/2006 5:24 PM:
"Roberto Quijalvo" wrote in message
news
Why replace them if they're working?
To find something more reliable.

How do you measure/compare their reliability ?
How can you be sure you do not replace something
reliable with something less reliable?
Just because switch is non-mechanical in a simple
sense does not necesairly mean it is more reliable.

Just because they haven't failed yet,
doesn't mean it won't.

It also does not mean it will.

There are countless tales out there of failed mechanical switches. I
don't have to personally experience the failure to prompt a change.

I would rather protect myself from the failure and build some
extra flood protection (one more, emergency top switch)
than to worry about replacing the current set if it is working.

Of course, that's not to say that the non-mechanical switches may not
have their faults too.

Then you realize this... ok, let's go back to my first question then :-)