OCLT test question

[jasonlk1]

I just read the oclt section how to perform. It didn't really answer my question directly so I thought I would ask.

Does the oclt need to be done at an FC of shock level or can it be done from any FC level? The directions say to just test it after no sun and at least 30 mins after chemical additions in the evening. Doesn't say it needs to be at or above shock.

I am just wondering because I was thinking of letting my FC drift down to normal levels today and test tonight then in the morning. I just wasn't sure if the test would be as accurate at let's say FC of 7 tonight vs an FC of 18 for my shock level. Just wondering, maybe it doesn't matter.

Thanks.

 

[jblizzle]

That is slightly controversial if you get into the chemistry details

The OCLT process was written with the assumption that you are in the SLAM process and thus your FC is a shock level. So the 1ppm loss is small relative to the high FC level.

You could do the OCLT at normal levels, but personally I may not consider a 1ppm loss as a pass and would prefer it to be 0.5ppm or less.

 

[tcat]

I thought at "normal" FC levels there should be no loss at night. So anything more than .5 would probably be something growing. I actually use the OCLT test at normal levels to test my auto-chlorinator function (how much FC it's adding).

 

[jasonlk1]

I will keep it at shock level for tonight's test then thanks!