Pool is green & we are closing next weekend.

[Mlquattro]

Hi,
I'm new to the forum and used my mom's TF 100 test kit today since I haven't been getting help from the local pool store. My pool has been green since the end of August and we are closing this coming weekend since the weather is getting colder quickly. On the advice of the pool store, we changed the sand in August when the water started turning green. We have had a rather rainy summer so I thought that may have contributed to the problem. After trying everything the pool store suggested with no luck, my mom suggested that we her test kit and the forum since her pool has been crystal clear since she started here with you guys. I have just started today, so bear with me as I don't understand the chemistry yet .

My readings today are as follows: Ph is 7.5; Ch stayed yellow after 40 drops; FC is 33; CC is 0; TC is 66; TA is 400; CH is 300; Cya is 90. I put 8 gallons of chlorine bleach a week ago to try to "shock" it. I put my numbers in pool math today, but am not getting directions on what to do.

Please help..... I have no idea where to start. Thanks so much! Michele Q.

 

[Texas Splash]

Welcome to the forum! You don't have much time apparently so let me get right to it:
- With your TF-100, you should list your results like this:
FC (33 is an odd number) Use a 10ML water sample, one scoop of powder, mix until clear counting drops. Cut that number in half (i.e. 40 drops = FC of 20)
CC Done right after the FC test
CYA 90 is too high. Lowered by a partial water change; I'll come back to that
pH: 7.5 is probably skewed because the FC is so high
TA: 400 is quite high; common in your area
CH: Not typically relevant for vinyl pools

You listed a "Ch" staying yellow. That was probably a simple OTO drop chlorine test. Disregard. The FAS-DPD (powder & drops) is best for FC testing. The "shock" you did won't help, and neither would changing sand at this point. The pool has been green for a long time, and it will take time to clear it following our SLAM Process technique. So at this point you have to be honest as ask yourself (and your mom) if you have time to dedicate to doing a SLAM Process. You would have to change some water as well to lower the CYA a bit. If not, you can just close it and deal with it in the spring and SLAM Process it then. We'd love to help guide you through a SLAM Process, but for a pool in your condition it could easily take more than 5 days to complete the SLAM Process, so you have to make that decision first.

Please review the SLAM Process page, talk it over, and let us know how you would like to proceed. If you decide to wait on the SLAM Process, you will still want to close the pool properly. So use the following link to help you with that to prevent any damage to the pool. We'll be standing by to help either way.

Pool School - Closing (Winterizing) Your Above Ground Pool

ABCs of Pool Water Chemistry