JBJ ATO weirdness?

reefm · May 24, 2016

I forgot to turn off my JBJ during the last water change and noticed something really odd, and honestly very concerning:

When the water level dropped completely below sensor 1 in the sump (Mode A = sensor 1 triggers MIN level), the ATO activated the pump just once, till timeout time, and then did not work again.

From subsequent tests it appears that if there's no downward motion on the sensor 1 float (example: water level well below sensor 1) the controller will not activate the pump again. So let's say you lose 2 gallons fast for some reason, the ATO will not replace that water, even if there's plenty of water available in the reservoir.

Has anyone else noticed this? Any workarounds?

RyanCSGO · May 24, 2016

Wait it ran the full 3 minute maxout run time correct? if that is the case then it activated the safety feature, which doesn't not allow it to operate again until the controller is reset.

reefm · May 24, 2016

RyanCSGO said:
Wait it ran the full 3 minute maxout run time correct? if that is the case then it activated the safety feature, which doesn't not allow it to operate again until the controller is reset.

right. So if it cannot replenish the water level in 1 cycle it will not try again, by design?

Tahoe61 · May 24, 2016

Which model number is the ATO?

RyanCSGO · May 24, 2016

Correct. its a standard safety feature in case a float gets stuck, this way the ATO doesnt just keep dumping water until the reservoir is dry.

what size is the the pump and tubing you have for the ATO ?

nitrodude · May 24, 2016

Yes. Because generally if your tank didnt get topped off in 3 minutes, the jbj assume float malfunction and stops pumping fresh water into your tank and prevents a flood.

Now, if it runs for 3 minutes and times out, if the float gets reset itll work again

reefm · May 24, 2016

thanks guys. Pump is a regular aqualifter with ~20 inches of airline tubing, handles regular top-offs ok, as expected. Just moved from a gravity float ATO to the JBJ and wasn't expecting the scenario of the JBJ not helping in the case of sudden water loss, but I see the design point of preventing a flood.

PS. funny but I designed the ATO volume exactly so it cannot overflow the sump, oh well.

RyanCSGO · May 24, 2016

I'm running the JBJ also, with the acella pump, 215GPH with a 1/2 hose, when the ATO kicks on it runs for about 12-15 seconds.

it would be a nice feature if you could adjust the safety time as you see fit. the 3 minute thing would definitely help me, but i would for sure still have some flooding.