Time to replace sand?

[jonno]

This morning the FC was 19ppm, down from 27ppm from 12 hours before. Also the CC was 1.0 so I'm still on the program. Added 1.3 gallons of 12.5% bleach to bring it back to 25 ppm.

I have someone to check it every two hours today and keep it at 25 and will see how it looks tomorrow. The water is quite clear - not crystal yet, but I can see the seams in the vinyl even in the deep end. I feel like this is home stretch and I'm not going to rush it. Thanks!

[Watermom]

I feel like this is home stretch and I'm not going to rush it. Thanks!

That's right. Don't rush it. Sometimes this is the point where people mess up. They get so tired of messing with it and it looks good so they think that they are finished and quit too soon. And, guess what? It's only a matter of a couple of days and they are right back where they started and ready to cry.

Hang in there. You're almost there!

[jonno]

Thanks for the encouraging words, they really help. I'll keep the FC at 25ppm until it holds within 1ppm overnight and the CC is no more than 0.5.

I've been keeping everyone out of the pool and will do so until this is done, but when I looked at the Best Guess chart, it looks like a quick dip might be okay and the high FC would pose no danger to the swimmer (although designer swim suits and dyed hair might lighten). However, I don't know if the pH and TA levels need to be considered. Several days ago, when I last measured pH (before I was keeping the FC so high) it was 7.2 and the TA was 170.

Watermom - What do you or the other experts think - stay out of the pool or allow a quick dip? (Of course, I would be sure an hour or so had passed since the last bleach addition).

So far today the readings are:
7:30a FC 19.0 (added bleach), CC 1.0
10a FC 25.0
Noon FC 21.5 (added bleach)
4p FC 23.5 (added bleach), CC between 0.5 and 1.0

I'll test again when I get home and post the overnight numbers.

[Watermom]

Maybe a quick dip before the next dose of bleach with an old swimsuit that you don't care if it fades. The TA and pH readings won't hurt anything.

EDIT -- Not an expert by any stretch of the imagination!

[jonno]

This morning's numbers showed that the FC dropped 3.5 overnight (from 26.0 to 22.5) and the CC was 2.5. This means I need to stay in the shock phase and continue testing every two hours to keep the FC at 25. I added .7 gallons this morning. Water clarity is almost sparkling - I can't believe it's the same pool. Almost there...

[CarlD]

Don't give up now! CYA still over 100ppm?
When the FC is down, since the CC is below 1, a quick dip in an old suit shouldn't hurt.
What is your pH? (I realize it will appear elevated).

Carl

[jonno]

Carl, et al, - Here are my 10am readings.
FC 25 (7:15am was 22.5 so added .7 gal of 12.5% bleach at that time)
CC 0 (7:15am was 2.5)
pH 7.6 (reading elevated from high FC)
Someone is testing for me while I'm at work -- every 2 hours and adding bleach to keep the FC at 25. I'll test the CYA tonight.

The signs of progress are amazing! The photos tell the story...


From opening day, 5/29/11, through 6/9/11 the water was Mountain Dew green with visibility about six inches (my hand would disappear before the water got near my elbow).


On 6/11/11, the pool store prescribed "Green to Clean" - it turned the water blue (killed the algae), but visibility was unchanged. This product just made things worse (see earlier posts).


I joined this forum on 6/13/11. The water was a mess. This was taken on 6/22, mid-way through the bleach treatment. The algae made a comeback, but visibility was improving.


As of this morning - the water has a sparkle to it. Seams and design are clearly visible on the very bottom of the deep end. The water probably isn't CRYSTAL clear yet, but to tell you the truth, it's been so long, I'm not sure I remember - every day it keeps getting better. Wow!

This forum (and the people behind it) is great! I know it is basic chemistry and POPP, but it seems like magic - thank you all!

[CarlD]

Getting the sparkle is easy...just put a little DE in the filter via the skimmer, enough so the pressure goes up 1psi (add about 1/3 cup at a time till you get there), then put a skimmer sock in the skimmer. In NO time the water will sparkle again! Mine does and I have a 200# sand filter.

Carl

[jonno]

Thanks Carl. I put a little DE in the skimmer and installed a skimmer sock. Looking even better than this morning.
7pm Test Results are:
FC 25.5
CC 1.5
pH 7.5
TA 180
CYA - black dot disappears well before the 100 mark.
pH and TA numbers may be off due to high FC ppm.

[jonno]

Carl, Watermom, Janet, or Ben -
I have a question about the timing of taking an end-of-day FC test and when to take it the next morning. To end the shock phase, I know I want a FC that loses no more than 1ppm overnight, but when does "overnight" start and end? From reading other posts, I thought the last test of the day can be taken whenever the sun is off the pool and the first test the next morning is to be within two hours of sunrise.

This evening, I did a test at 7pm and the FC was 25.5. I thought that was late enough to be my final test. Out of curiousity, I tested again 3 hours later at 10pm and was surprised that the FC dropped 4ppm (from 25.5 to 21.5). I added almost a gallon of bleach to bring it back to 25ppm, but this got me wondering.

Here're my questions:

• Why did the FC drop so much between 7p and 10p?
• Is it because the FC is still fighting nasties in the water? The CC at 10p was 1.5, so I think this also is a clue that the shock level of bleach is still needed.
• The sun didn't actually set until 8:38p tonight - could the UV rays hitting the pool indirectly between 7p and 8:38p also have contributed to the drop in FC?
• The water is so invitingly clear, how many more days should I be prepared to continue frequent testing and keeping the FC at shock level (i.e., 25ppm)?

Sorry to be hounding you with so many questions - I'm curious about the chemistry and I've also got several eager swimmers attracted to the sparkling water.