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derek
12/29/2009, 09:59 PM
I have an AQT controller on my fw plant tank. Yesterday it didn't turn off the CO2 and killed most of the fish. My question is how do I determine what happened? I had been using the controller for about a month and it had been working fine. I could hear when the solenoid opened and shut. I had the pH set to control the solenoid at 7 - 0.05 to +0.10. When it failed the pH went down to 5.5. After unplugging the solenoid the plug was on for several hours. When the pH was about 6.7 I rechecked the program and it seemed to be OK, but I reentered it again. At that point I heard the plug click, but it was still on. About a half an hour later the plug was turned off by the controller.

The controller is still handling the temp and lights fine. So it seems to be a pH program issue. I have not done any updates since I got this controller in 1/2009.

So how do I figure out what went wrong and prevent it in the future?

Thank you for your help.

Derek

RobbyG
12/31/2009, 12:14 PM
Hi Derek sorry to hear that. I am not sure from your description exactly what happened, is it that you figure the Plug was stuck ON in which case my only suggestion is to switch plugs, and label the bad one as faulty (or get the powerbar repaired or replaced.)
The second possibility is that some other program high jacked your pH program and took control. Do you have any XY programs or any other programs that have access to that Plug?

I had a very similar incident which was caused by me actualy removing the pH control from the pH probe because the probe had gone bad (old age) and instead I temporarily put the pH solenoid on a timer. Well The Temporary timer was keeping the pH in the reactor so well balanced that I let it stay for months, then one day my Young Son got hold of the CO2 tank and turned up the bubble rate. My SMS module alerted me that the Tank pH was at 8.0 then later 7.9 when I finaly got home it was at 7.7 and I lost two expensive fish and a few corals.

My only improvement advice is for you to add in some redundancy. You could put two solenoids in the CO2 line and then use two plugs and have two seperate programs. That way if anyone fails the other one will shutdown the Co2. Its a clunky kind of fix but I use something like that on my Ro because I just dont trust a solenoid valve, and when they fail its always stuck open and creates a major disaster.

derek
12/31/2009, 04:13 PM
RobbyG,

I am not sure that it was the PU because when I manually cycled the plug from the controller if turned off and on fine. There are only 2 other things being controlled. One is the light and the other is a heater. They are on other plugs and have been working fine.

I have had solenoids fail because the valve seat has corroded or something like that.

Thank you for the suggestion on the redundant solenoid.

Derek

nemo's janitor
01/01/2010, 02:08 AM
It is my guess that it is a faulty PU. I have had many PU's that have had an outlet socket go bad. They start by intermittently jamming on until they are eventually jammed permanently on. A hard bump on the side of the PU sometimes releases the stuck relay. I have asked Aquatronica to improve the fail safe it this regard. Well at least to include the actual status of the outlet socket. Water can be pumping out all over the place and one can not see what is wrong by viewing the Controller, PC real time monitor or the realtime monitor via the Ethernet or AquaStats.

Something else it could be is that a manual command has being reinstated. Let me explain.

If one gos to the PU menu and then to the manual override option and switches an outlet (on or off) to perform a maintenance task be very careful as by resetting/resuming one would think that the manual command has been deleted. Not so. I have had it on most of the systems where the manual command reinstates itself after a small power out. It does not happen every time but i can assure you, Murphy has his way, the time you override the the main return or RO solenoid. That's is when it happens.

I have refrained from using the manual override option for this reason. Hopefully AQT will fix this bug some day.

derek
01/01/2010, 09:01 AM
Nemo,

Thank you for the information. Either of those problems sounds like a critical bug. The second issue is especially worrisome. With these problems I am not sure what to do. I do not want to have any more tank wipe outs.

Derek

RobbyG
01/06/2010, 06:00 PM
Nemo I am not doubting you but I must say I have never seen the outlet go back like that and I use mine in manual mode at least 4-5 times per week. Although now that I reread your postm I do have my whole system runnig through a UPS, so that may explain it.

nemo's janitor
01/07/2010, 02:09 PM
Yup Robby it does happen intermittently. This is possibly why the bug is so hard to find/fix. I must add that it does not happen on every system. Or should i say, it has not occurred on every system, and i cannot induce the bug every time on systems that it has occurred on. But sometimes it is induced. However it has occurred on more than one occasion on many systems that it occurred on previously. Hope that makes sense.

RobbyG
01/11/2010, 05:51 PM
Yup Robby it does happen intermittently. This is possibly why the bug is so hard to find/fix. I must add that it does not happen on every system. Or should i say, it has not occurred on every system, and i cannot induce the bug every time on systems that it has occurred on. But sometimes it is induced. However it has occurred on more than one occasion on many systems that it occurred on previously. Hope that makes sense.

Yeah I know what you mean, I have seen those "Ghost Problems" when I use to work on Home Theater systems. Customers would spend 10 minutes telling me their not crazy when they could not reproduce the problem.
I use to tell them not to worry because I have had things like that happen on my own equipment and no matter how hard I try to find a method to reproduce it I can never do it again at will, it just happens randomly. What I have found in the one or two cases I did solve was that it was due to Internal grounding issues, a little stray voltage just Biases ON some semiconductor. I bet it's some stray voltage that causes it in the AQ powerbars.
Try a grounding rod on the system and see if it goes away.

derek
01/13/2010, 06:58 PM
I was wondering if anyone from AQ has any suggestions about what went wrong with my controller or how to trouble shoot it? I am not comfortable relying on this to control the CO2 until I have a better idea about what may be the problem.

Thanks.

Derek

derek
02/01/2010, 07:08 PM
Hi,

I was wondering if there was an email address for AQT support? They used to monitor this forum, but I guess that is no longer the case.

I would like to figure out what the problem is with this controller.

Thank you.

Derek

ReefWreak
02/02/2010, 07:41 AM
Check out aquatronica's site, aquatronica.it for contact information.

A consideration that you may be interested in if you are worried about repeating the same circumstance is to have an audible alarm sound if the pH drops too low from the CO2 being stuck on. You could also program a different outlet to power an air bubbler in the tank (next to where the CO2 is being diffused from) to effectively neutralize as much as possible the CO2 being dissolved. With the aquatronica it's easy to combine the two and have them "trigger" when the pH gets too low, and that way you'll have double fail-safe in case something goes wrong with the outlet.

Hope that helps, and I'm sorry to hear that you lost your livestock :(