unexpected test results

[hyperionguy]

Background:
I have a TF-100 but haven't been using it b/c for 2 months now I was expecting to drain the pool any day b/c of landscaping I'm going to get done. I have just been winging it so far, just using the OTO test to make sure I had at least the minimum FC. It's worked out so far.

Well, now that I KNOW I'm taking it down within the week, I decided to test my fill water and for jollies test the pool water and play if I felt like it.

Fill water:
Ph 7.5
TA 120
CH 130 (doesn't matter)

Pool water:
Ph below 6.8
TA 20 (totally surprising)
FC 1ppm
CC .5ppm
CYA 130 (oopsie!!)

I was just throwing in dichlor b/c I had some laying around and I thought the fill wasn't going to last anyway. Wow, it's higher than I thought.

Anyway, the two things I didn't expect are:

1) The TA drop from fill 120 to pool 20. I didn't have that last year. Don't know what happened. For fun I added baking soda to raise it. Of course, I input the wrong # of gallons in the pool calculator. So it jumped more than desired. I was shooting for a first step of 20 to 70. I ended up with 120. Even when I corrected the gallons and played with the target TA until the baking soda add matched what I put in... the target TA for the oz I put is should have been 90. Don't know why it went to 120.

2) I added the correct amount of 8.25% bleach to bring FC to 20. Tested it and was spot on. That was in the evening. This morning it was 12ppm. I added enough this morning to bring it to 16ppm. This evening it is back to 12ppm. It is difficult to figure out what is happening b/c in addition to whatever organic material is already in the pool, we had 1-2" rain last night and .5" this afternoon. So that's messing with me.

I'm draining this coming Monday, so not urgent... just curious mostly about the TA info if anyone has any insight.

 

[jblizzle]

pH and TA crashed and the CYA went up due to the use of all the dichlor ... as I think you know.

Not sure why the FC additions are hitting the target but the TA is not ... could just be within the accuracy of the tests.
And certainly the FC is dropping quickly due to some organics in the water since the FC was WAY too low for the higher CYA.

 

[hyperionguy]

Yes, I know why CYA went up, I was just surprised how quickly as I wasn't calculating what would happen, figuring I was draining soon (didn't happen). In my first 3-4 readings of pool school I guess I didn't pick up on the ph and ta crash due to dichlor... interesting! Sorry I missed that.

I'm discovering that there is a wide range of results with the TA test. I'm discovering there is a big difference between when the solution turns pink and when add'l drops produce no further color change. that isn't in the kit instructions. also the results from one sample to another varied. when testing fill water, there were a number of drops where a drop produced pink, which faded, then pink... faded... finally pink that stuck. Pool water testing produced an instant switch to bright pink. No fade. Interesting.

I guess I have more learning with the tests.

 

[jblizzle]

Have you seen this?
extended-test-kit-directions-t25081.html

 

[hyperionguy]

Interesting read.

I promise that when I refill in 2 weeks I will re-read everything pool school and get back on the ball. I used to have a handle on it, but it's been almost a year... my retention span is shorter than that. Sadly.

Thanks for pointing out

... as I think you know.

I guess you told me.

ha. kidding. appreciate your input. And yes I do know. I've been around awhile :-D

Oh... and your patience. I've seen your posts in other threads where you held your cool longer than I would have. lol