Can old DPD powder show inaccurate high reading ?

[aswetich]

When opening my pool today I put two gallons of 10% chlorine in the spillover spa to help clean it up before firing up the pump. Before running the pump I tested the water in the pool and was very surprised how high the chlorine level was. Could my DPD powder from last year give a false reading ?


CC 4.5
PH 4.7
TA 140
CH 310
CYA 65
Salt 2.9 per Aqaupure
Water temp 50%



Now I have the pump running so the spillover spa with the two gallons of chlorine is mixing with the pool water.
I already ordered new DPD powder but it probably won't get here for a few days.

 

[Bama Rambler]

I'd test it again since the pump is running and see what it reads.
It's possible for the FC you read to be correct.

 

[JasonLion]

DPD powder can go bad, but it takes a really long time if you store it properly.

 

[aswetich]

My pump has been running 24 hrs so everything should be stabilized now but the pool is still very cloudy. I did a retest today and got the following readings.

FC =12 Also did the cheap OTO test and it was the darkest yellow I have ever seen it.
CC = 0
TA =180
CH = 320
SALT 2.9
CYA=50 It's been cloudy all day yesterday and today

I don't have the ability to test for TDS. Full service pool store is quite far away but I am going to try and get a sample there this week for a metals test. The pool was filled with trucked water about 8 years ago and I have been using well water to top it off ever since.

 

[Richard320]

My pump has been running 24 hrs so everything should be stabilized now but the pool is still very cloudy. I did a retest today and got the following readings.

FC =12 Also did the cheap OTO test and it was the darkest yellow I have ever seen it.
CC = 0
TA =180
CH = 320
SALT 2.9
CYA=50 It's been cloudy all day yesterday and today

I don't have the ability to test for TDS. Full service pool store is quite far away but I am going to try and get a sample there this week for a metals test. The pool was filled with trucked water about 8 years ago and I have been using well water to top it off ever since.

Who cares what TDS is? Cloudy is usually algae.

I'm just wondering if you didn't use the large sample (25 ml) but multiply for the small? (10 ml)

 

[aswetich]

Just to be sure I don't have a algae problem I shocked the pool yesterday. Using the pool school criteria I brought my FC up to 24 yesterday morning based on the CYA level and brushed it. Before going to bed last night I confirmed the FC was at 24. and brushed it again. When testing this morning the level remained at 24 so I would expect there is not a algae issue. I can see the floor drains but it obviously not as clear as it should be. Could there be dead algae floating around clouding the pool ? I ordered some DE to ad to my sand filter but is there something else I should be doing ?

 

[duraleigh]

How are you testing? YOu should NOT have been able to hold 24 ppm FC during the day. Sunlight consumes FC.

 

[aswetich]

I was probably able to keep the FC up during the day because I live in Michigan and the weather can be all over the place. The day I shocked it was almost dark as night. The FC stayed constant throughout the night so doesn't that mean the Algae is likely dead ? I have been using the DPD test for years and am positive it is being done correctly.

 

[duraleigh]

I brought my FC up to 24 yesterday morning based on the CYA level and brushed it. Before going to bed last night I confirmed the FC was at 24.

That's what doesn't work. You literally cannot go all day and not lose FC.....regardless of the weather.

 

[linen]

As duraleigh said, even with the conditions you listed, you should have lost some FC.

Did you have the aquapure Saltwater chlorine generator (swg) off or on? We recommend not using the swg during the shock process (saves some cell life). In addition, when you do the OCLT, the swg needs to be off.