Apex compatible powerhead upgrade

Clownfishy · Jun 2, 2022

gbru316 said:
I admit I haven't fully thought out the idea yet and I have absolutely no experience with Tunze or Apex. I'm making some rather large assumptions here that I'd poke at a bit more if I go this route.

I'm not sure what happens if the Tunze doesn't get a 0-10V control signal. If 0 volts = "off," then a potential failure mechanism exists where the Apex 0-10 Vdc control signal output drops out but because the mains power is still present, there's no indication that it's inoperable. In which case, you'd need to monitor that 0-10V signal. You'd have to define some threshold under which you consider "failure" -- maybe 0.1 Vdc, or 0.5 Vdc, the level doesn't really matter for the point of discussion.

You'd use hardware (would probably need a bit more than a relay) to make sure that the control signal > your threshold. If not, you'd use the relay to kill the mains power coming from the Apex power strip, which would kick the Tunze over to battery power. Or if that doesn't default the Tunze to local control, you could use the relay to apply a signal from another source, which could be something as simple as a 5v wall wart.

There's a few ways you could go about it, really.

I am a complete novice in this area but would love to reconnect my Tunze streams back to the apex and for them to switch to the batteries if the power or Apex unit dies. If you do anything in this area, I would really be interested.

Sean Clark · Jun 2, 2022

I love my Apex but like others have stated I would never "apex everything". My return pump and flow are not controlled by my apex and never will be. Those are two things that never need to be turned off unless you are performing maintenance.
As for adding powerheads to your tank, my vote is for Tunze.

gbru316 · Jun 2, 2022

This should handle any power loss event (you'd also have to find a battery). I might be wrong, but the transition from (failed) mains to battery power should be automatic -- handled entirely by the Tunze controller.

Per @ZombieEngineer The loss of control signal from the Apex to the VDM can be mitigated by utilizing VDM fallback states.

The other failure situation -- where you have a malfunctioning VDM and subsequent loss of control (and you're totally unaware of it because the Apex thinks it's operating just fine) -- is what my relay solution would address.

And really, any solution depends on what type of peace-of-mind you want. Some people are probably ok with just notification that something that failed so they can take action. Others want true redundancy, where the system handles the failure, keeps working (maybe in a reduced state), and notifies that the failover has occurred.