Knuckle-Headed UV Setback Caused by Automation Error

[Squist]

Opened up my UV sterilizer yesterday to take a closer look at how the quartz sleeve was doing; needed to see how clear it was. I've been growing more algae (GHA and diatoms mostly) than expected. Especially since I was making good progress with my tank's ugly phase since adding a 25W sterilizer 3 months ago early Feb 2019.

To my surprise, the UV was rendered useless by a thick hardened white crust that had formed on the quartz sleeve. So soon? The sleeve was brand new, crystal clear three months ago.

I realized the mistake I had made almost immediately. Wanting to share this in case anyone is inadvertently making similar same mistake.

What I thought was a smart thing to do: "Apex: Turn off the UV when the main return pump is off -- so not to add unecessary heat to the sump" was a mistake. For several months (up until March), I had Apex routines turning off my main pump twice a day prior to when my feeder activated; goal: keep food in the display and not in the sump.

Because of space limits, I have my sterilizer installed upside-down. It drains when the pump is turned off. Ideally, I'd have it set up so it couldn't drain. But I don't.

When the feed auto-routine ran 2x/day, the main pump would turn off -> the UV sterilizer pump would turn off -> water drained out of the UV chamber -> the hot lamp evaporated residual water -> calcium deposits formed a crust on the glass sleeve of the UV -> blocking UV light when the sterilizer turned back on to the point of total ineffectiveness.

 

[sfsuphysics]

Wow with that encrusted sleeve it really starts to look like a traditional fluorescent bulb

That said, hopefully you found a workaround to make it work, maybe make sure the pump is on for at least an hour after UV is turned off? (not sure how long it would take to cool down).

 

[thanh510]

I followed the manual to the tee when it comes to mounting. They highly recommend mounting it horizontally but with the output/input up. I figured it had to do with the element heating up! Now we know why!

Thanks for sharing your mistakes so we can all learn.


Sent from my iPhone using Tapatalk

 

[Squist]

I followed the manual to the tee when it comes to mounting. They highly recommend mounting it horizontally but with the output/input up. I figured it had to do with the element heating up! Now we know why!

Good point! Revisiting the title of this thread, the root cause has less to do with automation and more to do with how I installed the sterilizer. You're right: the in- and outputs when pointing up will keep water from running out and release air if any enters. (Trouble for my setup: not enough room for the plumbing.)

 

[Coral2Coral]

Thanks for the heads up! I am looking into getting a few UV Sterilizers. Due to my setup, I would need to mount the UV upside down between the return pump and the return line. Do you think installing a siphon valve between the pump and UV would keep the water in the UV?

 

[Squist]

For my fix: I'm just not going to turn off the pump like I had set systems to do on a schedule. If I need to turn off the pump, I'll first turn off the UV lamp to let it cool. Then turn off the pump.

 

[sfsuphysics]

Yeah definitely would not automate the turning off of the UV sterilizier unless you can put in some programming language (I'm assuming this is on an Apex?) such that if the pump to it is off (and if you have the newer Apex the power needs to be detected) the sterilizer doesn't automatically turn off.