Help with test results...

[coreyadam]

Hi guys and gals...
I'm opening my pool after the first winter since building the pool last summer. Everything wintered well and I'm pretty much up and running for this season!...Very excited!! I'm having a bit of confusion, however, with my test results. Before starting my SWG, I cleaned everything very well and added enough liquid chlorine to shock the pool a couple times (using pool math, of course) and have had the pump and filter working 24/7 for a few days now. The water is crystal clear and all is good...except my test results. A little more background...after I shocked the pool the first time, the FC level dropped back down to 3ppm in a couple days. I shocked it a second time 2 days ago (using enough chlorine to bring it to about 10 ppm (using pool math...I added one full 5L jug of 10.8% liquid chlorine). Now, 2 days later, my FC tests at 23 PPM. I'm totally stumped at how that could happen. I have been playing with the settings of my SWG a bit in the past couple days, however, it has not even been running most of the time.
Here is my full test results from earlier today... FC 23ppm, Ph 7.5, TA 135, CYA 35, CH 125...and my salt reading on the hayward pro logic computer is 3000, while the test strips are only showing 2600 ppm.
...First, I'm very confused over the high FC reading (although it read 34ppm after the first time I shocked it, even though I only used one 5L jug of 10.8% chlorine, but went back to normal in a couple days). Second, my TA was happy all season last year between 90-110...I'm not sure what caused the jump to 130-140 for startup this year. Third, why would my (nearly brand new) Salt cell be reading 3000ppm when the test strip only reads 2600ppm? Even though the cell looked clean, I did soak it in the acid solution and rinse really well before reinstalling. It literally only has 3 months of use.

Any feedback is greatly appreciated, as always!
Thanks!
Adam

 

[Azgirl71]

I would leave the SWG off and let your FC drift back down and retest everything after FC is below 10.

 

[woodyp]

Trust the reading on your SWG-------NOT the strips. Taylor makes a drop based test which is preferred if you'd like to try it.

 

[coreyadam]

I would leave the SWG off and let your FC drift back down and retest everything after FC is below 10.

Thanks...that's what I'm doing now...but I just don't know how it got so high to begin with!?? Also, what is the highest level that is safe for swimming? The kids are hoping to go in tomorrow!...lol

- - - Updated - - -

Trust the reading on your SWG-------NOT the strips. Taylor makes a drop based test which is preferred if you'd like to try it.

That's what I figured...but I would like to have an accurate test that I can verify my SWG readings periodically. I'll check it out.
Thanks

 

[Azgirl71]

As long as your FC is below shock level for your CYA then they can swim safely.

 

[coreyadam]

As long as your FC is below shock level for your CYA then they can swim safely.

That's what I thought I read before....thanks!

 

[Azgirl71]

That's what I thought I read before....thanks!

No problem.

 

[coreyadam]

I'm still so curious as to why my FC level got so high though? Any thoughts on that? Is it possible that I'm getting inaccurate results from my TF100 test kit after the winter? (I just bought it last year)

 

[Azgirl71]

Was it stored indoors during the winter? If so it should not be bad from what I have read. If it was in a garage or shed it could have froze during winter.

I thought maybe when you were playing with you SWG it was defiantly working and pushed your FC up.

 

[pooldv]

..First, I'm very confused over the high FC reading (although it read 34ppm after the first time I shocked it, even though I only used one 5L jug of 10.8% chlorine, but went back to normal in a couple days).
How many ppm FC does 5L add? And what is normal?

Second, my TA was happy all season last year between 90-110...I'm not sure what caused the jump to 130-140 for startup this year.
Don't know why, but leave it for a couple, few weeks to see what happens.

Third, why would my (nearly brand new) Salt cell be reading 3000ppm when the test strip only reads 2600ppm?*
Test strips are +/-500ppm. If the SWG is happy then we are happy. Doesn't really matter what the test strip says.

 

[coreyadam]

Was it stored indoors during the winter? If so it should not be bad from what I have read. If it was in a garage or shed it could have froze during winter.

I thought maybe when you were playing with you SWG it was defiantly working and pushed your FC up.

it was stored in the shed over the winter (by mistake...)... would this affect its accuracy? And thats a possibility with my swg....although i really didnt think so.... we'll see...because its off now.

- - - Updated - - -

How many ppm FC does 5L add? And what is normal?

That was supposed to bring me to 10ppm. and it went back down to 3ppm which is what i called normal...

If the SWG is happy then we are happy. Doesn't really matter what the test strip says.[/QUOTE]

Thanks!

 

[Azgirl71]

Yes if it was not stored in a controlled temp environment then you may need to order refills. You don't want the reagents to get to hot or to cold.

 

[coreyadam]

Yes if it was not stored in a controlled temp environment then you may need to order refills. You don't want the reagents to get to hot or to cold.

Thanks... but is there any evidence of it throwing the results off by that much?

 

[Azgirl71]

Sorry, I don't have any evidence other than what I have read on here. Maybe someone else can tell you why.

 

[jcowart]

A few quick questions for you. When you tested fc at 23. How many drops did it take to go clear. 46 for a 10 ml or 96 for a 25 ml sample. It could be a number of things from math errors, volume error, to strong bleach. I had Wal-Mart 8.25% bleach test at almost 12%. The date code showed it was 2 days old and consistent. Yes test strips can be off that much. That's why they are not trusted.

 

[coreyadam]

A few quick questions for you. When you tested fc at 23. How many drops did it take to go clear. 46 for a 10 ml or 96 for a 25 ml sample. It could be a number of things from math errors, volume error, to strong bleach. I had Wal-Mart 8.25% bleach test at almost 12%. The date code showed it was 2 days old and consistent. Yes test strips can be off that much. That's why they are not trusted.

It was 46 drops for a 10ml sample. Today it was down to 18ppm (36 drops for 10 ml sample). I actually have specific pool chlorine (only cuz it was on sale...) so I can only assume it's accurate.

 

[wackybrown]

Always balance the water PH in your pool before you add any chemicals. I saw a huge difference in getting my readings accurate after that lesson.

 

[coreyadam]

I still haven't figured out why my FC level spiked so high...and maybe I never will.... very strange, since I followed the pool math exactly. Anyway, on another note regarding storing the test kit chemicals... I came across this post while searching for info and it has a link to a Taylor bulletin regarding storage of test kit chemicals. For me, I was interested in the part that states that any liquid testing agent that was frozen may be thawed at room temperature and be fine...as long as the bottle hasn't cracked and there is not any floating particles or crust around the opening....I'll post the link to that thread. http://www.troublefreepool.com/threads/7826-Taylor-Tech-Bulletin-for-Storage-of-Reagents

- - - Updated - - -

Always balance the water PH in your pool before you add any chemicals. I saw a huge difference in getting my readings accurate after that lesson.

My pH was at 7.6, which is fine for me... I was getting the same TA reading at that point. I added some muriatic acid that I had for cleaning my cell, in hopes of dropping the TA. It did drop my pH very slightly, but didnt' seem to have an effect on my TA... I'll continue to monitor it...

 

[pooldv]

Adding MA in itself will not lower TA. Here is the article describing how to lower TA by adding acid. Lowering Total Alkalinity

 

[coreyadam]

Adding MA in itself will not lower TA. Here is the article describing how to lower TA by adding acid. Lowering Total Alkalinity

Thanks...but I read that article...and it actually states that adding MA is exactly what will lower my TA. However, it did inform me not to really worry about it, unless it was causing one of these 2 problems...here is a quote from that article...

"There are two reasons to lower your total alkalinity (TA) right away, because you want to slow down the rate that the PH rises, or if high TA is contributing to a high calcium saturation index (CSI) which puts you at risk of calcium scaling. You shouldn't lower TA just to reach a target number. Make sure you actually have one of the above issues before lowering your TA."

I am not having either of these problems...and was simply trying to get the TA closer to the target number that I've learned in pool school...or, at least, down to where it was last season, which stayed between 90 and 110. Anyway, thanks for the info...I thought I had read alot about it...but had never actually read that post.