OCLT: FC is higher in the morning.

[hpdad]

After shocking process about a week, I did perform OCLT yesterday and today. And the result is confusing.

Yesterday result:

FC = 27 (the night before)

FC = 29 (in the morning)

I was confused so I did another one just this morning.

FC = 22.5 (last night)

FC = 25 (morning)

What is possibility here? bad patch of reagent?

I followed exactly at these step:

pool-school/overnight_fc_test

Edit: I want to add something. I have the kit K-2006 but the R-0871 was out after 2 days, so I ordered the reagent. The result from the new R-871. That was why I asked may be because of bad reagent?

 

[FamilyGuy]

Your swg producing chlorine with no loss at night would be my guess( unless you turned it off)

 

[woodyp]

Did you leave the SWG running overnight?

 

[duraleigh]

Chlorine cannot be increased in your pool unless you add it. Are you running your SWG or have pucks adding chlorine?

 

[hpdad]

SWG is off at all time of the process, and no pucks, nothing in it.

Edit: I want to add something. I have the kit K-2006 but the R-0871 was out after 2 days, so I ordered the reagent. The result from the new R-871. That was why I asked may be because of bad reagent?

 

[Suziqzer]

How long did you let the pump run before you took your test at night?

 

[Suziqzer]

... after adding chlorine I mean

 

[hpdad]

... after adding chlorine I mean

The pump run 24/7

 

[karmabiker]

I would double check that SWG...

 

[JohnN]

I had this same thing once and just attributed it to testing error. Since you had it happen twice, I think there is something else going on. You had the filter running for at least 1/2 hour after adding chlorine and before doing the night test, correct?

 

[hpdad]

I know it's weird. The first time could be understandable because the pump was running, adding chlorine so there was may be the errors. But for second time, I turned off the pump and not adding chlorine since yesterday long before I took the measure. Anyway, I would keep my eyes on this today.

The SWG was off during shocking process.

 

[Smykowski]

You never answered Suzie's question, and I agree with her hunch. After putting your evening dose in, wait at least 30 min (in this case more might be better) before doing the test. If it's not mixed well enough in the evening, but it is mixed well enough in the morning, that could be the sourceof the discrepancy.

 

[ping]

A couple more things to watch for, make sure you get the water sample from the same place and depth in the pool, and that you put in enough powder in the test. Two generous scoops of powder should do it.