How to failsafe/back up dosing pump?

[chaostactics]

I'm about to set up a Jebao dosing pump. Im going to be using it to dose all for reef and AB+. I am going to fill the dosing containers with 1 week volume of each.

I have an Very 2016 Apex I will be plugging it into. I was wondering if there was any way anyone could think of to failsafe the dosing pump (shut it off at the EB832 with the Apex) if the pump gets stuck in the on position?

TIA

 

[blaxsun]

I guess you could use the Apex to only turn the doser on for set intervals. That way it can never be stuck permanently on.

 

[ariellemermaid]

I'm about to set up a Jebao dosing pump. Im going to be using it to dose all for reef and AB+. I am going to fill the dosing containers with 1 week volume of each.

I have an Very 2016 Apex I will be plugging it into. I was wondering if there was any way anyone could think of to failsafe the dosing pump (shut it off at the EB832 with the Apex) if the pump gets stuck in the on position?

TIA

Is that a thing that’s known to happen? Never considered a dosing pump getting stuck on and never read about that as a common issue. That’s a tough one considering the check is a titration test you can’t monitor for continuously.

The idea above is one. I haven’t found my jebao to lose the clock after being off for a few days so it must have some kind of clock battery in there. But if it’s only on for a few minutes a few times a day that could be a problem for the clock.

Here are some half-baked ideas:
1) If the pH increases or decrease more than a certain amount in a certain period of time, turn off.
2) The pump must use more power when running, so if duration of power draw >x seconds, turn off.
3) A combination of these; if ph rises by more than x and power draw is “on,” turn off.
4) The suggestion in the above post, however, turn it right back on. Turning it off while it’s on and then right back on should end the “on” cycle. Issue with this is the jebao clock drifts, so it wouldn’t be in sync perfectly with the Apex.

The continuously monitored parameters are time, pH, temp, and power. (Plus ORP and salinity if you have those). So that’s pretty much all we have to work with here.

Also reconsider the project. I have no idea what the GPH on the pumps is, but you could do your own test with some water and a measuring container and the prime function. So first figure out how long it would take to dose what you’d consider a fatal overdose. This depends completely on tank size and the solution you’re dosing. If we’re taking about running continuously for half an hour, that’s something you can probably work with. But if it’s 5 minutes, that’s a problem and would be very difficult to catch. I mean the Apex only records the pH every 10 for instance. And before too terribly long, the clock on the jebao will drift by 3-5. I guess diluting your 2 part could adjust these times though.

 

[ariellemermaid]

I was looking for something unrelated then ran across this post about how to do the apex programming for detecting rapid pH change. There’s a lot to it, but could get the job done potentially. Looks like someone already thought of it.

 

[ariellemermaid]

Rather than the 30 virtual switches above though, I think using power is far simpler and could probably be accomplished with just 1 virtual switch and a Defer command.

Now I’m a little paranoid because I did find reports of someone using a jebao pump that got stuck on and killed the whole tank.

 

[a.t.t.r]

I have been thinking about this lately on the wifi model powering it on and off does not seem to impact it at all. Could put it on a timer and only have it on 5 minutes before and after the scheduled dose. . . I am still debating it or if power cycling could long term cause more issues with programming (not sure how good its internal memory really is).

 

[chaostactics]

I was told they don't pull enough Amps to register on the 832 in any meaningful way. That was my first instinct

 

[ariellemermaid]

I have been thinking about this lately on the wifi model powering it on and off does not seem to impact it at all. Could put it on a timer and only have it on 5 minutes before and after the scheduled dose. . . I am still debating it or if power cycling could long term cause more issues with programming (not sure how good its internal memory really is).

I’m sure the programming and WiFi info is stored on non-volatile memory so I’d be more worried about whatever battery keeps the clock going. Could still be a concern long term with a ton of power cycles though I guess.

I was told they don't pull enough Amps to register on the 832 in any meaningful way. That was my first instinct

Amps I’m sure, but you can use watts too. If it draws 2 watts for instance that’s only 0.02 amps. I’ll have to test it out holding down the prime on an empty head and see what happens, but yeah if the power draw is super super low that could be an issue.

 

[ariellemermaid]

Eureka! My DP-4 registers 0 watts when in standby but 2 watts when a pump is running! So here’s my code:

Virtual switch DosFail:
Fallback OFF
Set OFF
If Output Doser_2_5 Watts > 0 Then ON
Defer 002:00 Then ON
Min Time 999:00 Then ON

[two minute defer example, this determines how long before the above line is activated. Min Time keeps it off for about 16.5 hours]

Doser Plug:
Fallback OFF
Set ON
If Output DosFail ON Then OFF

Then under email alarm:
If Output DosFail ON then ON

This would need to be adjusted for your device. For instance I have one plug that registers 1 watt when it’s off with nothing plugged in, so Watts > 1 makes more sense. Also mine is on a 20g tank with little dosing so 30 seconds to 1 minute should be sufficient. You’ll have to figure out how long your Doser typically runs based on what you dose and set the defer above that. I have noticed via a Watt alarm that every so often the outlet will dip above 0 but just for a second, not enough to impact this code but I might go with >1 if testing shows that works too.

Might not work for everyone’s Doser but early testing with short defer shows it works for mine. This was a fun project! And I learned about another possible point of failure