View Full Version : In-line heaters?

California Crow
11/20/2008, 06:20 AM
I'm thinking of installing an in-line heater (Hydor ETH) for my new 39g nano build, since sump space is scarce. I'd be putting it somewhere on the circ return line. The heater can't be run 'dry', though, so I'm wondering how to handle the times when the circ pump may be off temporarily... feeding, maintenance, etc. Two things come to mind.

The simplest approach would be to just place the pump and heater on the same switchable power circuit, but that would mean using the heater's thermostat for temp control rather than my controller. Another that I think would work would be to put a check valve just below the heater inlet, thus holding water in the heater when the pump is off.

Thoughts/suggestions? Is this even something I need to worry about at all?


11/20/2008, 07:09 AM

If you have a feed cycle on a controller (Just my thought), make the heater turn off with the feed pumps. Or, the switch idea.

I avoid check valves like the plague; just one more thing to wear out/fail/break. Usually at the most inopportune moments.

The ETHs are good heaters; I ran one on an old tank and loved it; it just doesn't work with my new setup, regretfully. Oh, and I do believe Hydor has run-dry circuitry in it; so it shuts off.

I wouldn't recommend "tripping" the safety all the time as your means of protection, though.

California Crow
11/20/2008, 07:17 AM
I'm thinking that this is one use where check valve reliability isn't that much of a factor, though. Worst case is that it fails, and I fry the heater. Minor, compared to depending on it to prevent accidently syphoning your tank. I'd forgotten about the 'run dry circiutry feature; I was keying more on the 'don't allow to run dry' statement in the heater's instruction sheet. I guess it's not really much of a concern.