"Velvet" wrote in message
...
Rick wrote:





drill a small hole in the intake just below the water line, that way
if if
starts to leak out of the canister it can only leak to the level
where the
hole is at which time it will start sucking air and the siphon effect
will
stop.

Rick



Ah, I see! Not a bad idea, that. Presumably you're looking at
replacing
the filter if that happens though, due to impeller spinning in air/no
cooling?

--


Velvet

I'm not sure if that happens in practice. As soon as sufficient air
enters the siphon hose, the filter is no longer working in a closed loop,
where the weight of the water in the 2 hoses cancel each other out. Now
the filter needs to push water up with no help from the weight of the
incoming water and they are not designed to work under a lot of head
pressure. I don't think that they would be able to run bone dry, maybe
just having the water in the return hose bouncing up and down. What do
you think? It might still overheat eventually, and with evaporation
would go dry eventually, but for a few hours, or even a day or two, I
think it would survive. I recently found a 304 which had been run 'dry'
(water change went below the intake) for 3 days. It was hot. I cleaned
it out (rotten egg smell), plugged it in and it was dead, but a few days
later when I went to service it, it was working fine. I guess it just
needed to cool down a bit.
--
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