Can you simulate the OCLT?

[Auburn02]

Silly question, but I'll ask it anyway. Is there any reason you couldn't scoop up a 5 gallon bucket of pool water and put it in a dark spot for 6 or 10 hours to simulate an OCLT, testing it at the beginning and end of that period? Like maybe you really think you'll need to start a slam but don't want to wait until the next day, or you just don't like waking up before the sun, or maybe you live in Alaska and the sun just never goes away!

Maybe there are other factors I'm not taking into account, but I suspect it should be just fine. Most people's pumps don't run all night anyway, so that wouldn't be an issue. Can't think of anything else.

 

[mknauss]

No ---- the pool water is in contact with many surfaces. Skimmer throat and weir, light niches, ladders, steps, etc. All of those can harbor hidden algae. If you remove the water from those items, then it will not be effected by the algae on them.

Also, the OCLT does say to run the pump. We give the option to run it for 30 minutes prior to testing in the morning if that is better for the pool owner.

 

[Auburn02]

Ah, duh. Was thinking if the algae is in the water, it's in all the water equally. Didn't even think about the surfaces.

Also, the OCLT does say to run the pump. We give the option to run it for 30 minutes prior to testing in the morning if that is better for the pool owner.

Wait, really? I never have, and that may be why my previous ones passed, but that's not mentioned here: Perform the Overnight FC Loss Test (OCLT) - Trouble Free Pool

edit: it is in the video, though. Doh.

 

[mknauss]

but that's not mentioned here

Good point. I will see about getting that added.
Thank you.

 

[Donldson]

Like maybe you really think you'll need to start a slam but don't want to wait until the next day

I've never understood this line of thinking. If you think there's a problem then start it today. You don't need to run a diagnostic to raise your FC level if you think something is wrong, just raise it and worry about running an OCLT later. There's very little downside to raising the FC to SLAM level, some will burn off in the sun but mostly you'll just stop adding chlorine for a day or two. Minimal loss, but failure to get on a problem ASAP? That could literally lead to days of extra work. I guess I just wonder why people are nervous about raising the FC level.

And you're right that the OCLT rules don't show it. IMO it is implied since you have to dose the chlorine and then test 30 minutes later and it doesn't specify to shut the pump down. Since most OCLTs are (or should be) run during a SLAM and the pump is running 24/7 then it follows it should be running for the test. But you are right it's not specified and hopefully that gets added.

 

[Auburn02]

Won't argue with you there JD, all good points. Just seen many a thread where a user says "I'll run the OCLT test tonight and if I fail I'll start tomorrow" or the same was suggested by the forum experts to a user who thinks they *might* have something brewing, so that made it into my round of examples.

I do most of my pool stuff in the evenings so even if I wanted to try it, the daytime OCLT isn't very logical in my case.

 

[Newdude]

Just seen many a thread where a user says "I'll run the OCLT test tonight and if I fail I'll start tomorrow

+1. For many they *might* have a problem and it’s not the highest urgency to stop the bleeding. For many of those folks it’s already later in the day and waiting a few hours isn’t going to change much.

Personally, it would come down to risk assessment. if I had any reason to believe that I’d fail, I’d dose now and be pleasantly surprised if I was wrong and passed.

If it was a ‘well I should probably run an OCLT just to make absolutely sure I’m ok’ situation, I would most likely just wait.

Then again….. again…. Lol. The time of day could swing me one way or the other too. At 5:30 AM before work i would be a lot more apt to shoot first and ask questions later. With the sun on its way down at 2:30PM, I’d think ‘what’s done is done’ and wait.

Dang it Auburn !!! Now you got me arguing with myself !!! Thanks a lot.