Initial test results...green ring, combined chlorine...HELP!!!

Wow you guys are amazing. As a first time pool owner, finding this site before installation was a blessing.

We had our pool installed just over a week ago. (16x32 vinyl lined IG). Initially, it was only partially filled and we now have a greenish ring around where that initial waterline was. You can't feel it and can only see it if you are specifically looking for it, but it drives me CRAZY. My friend suggested trying a scrub brush as the vacuum doesn't help at all.

Yesterday I had a test done at the pool store and left without buying the oodles of chemicals they insisted I needed. I did buy CYA, but only 6# rather than the 12 they recommended. I added about 4# yesterday and it is completed dissolved tonight. This is the only chemical other than bleach that I have used. I just opened the Taylor 2006 test kit and have these results:

TC 7.5 (I added 3 gallons of 6% last night as water was looking cloudy and we were previously without any stabilizer. Pool store wanted me to add 5 gallons of 12%)
CC 0.5
PH 7.4
ALK 120
Ca 120
CYA less than 30 (but the dot does disappear before the top of the vial)

Any advice on clearing the CC? Eliminating the ring? Should I still wait a week before adding more CYA?

Thanks so much for your help :)

Hi Sheri, and welcome to the forum!!!!

You've done a good job in educating yourself before your pool was filled, and that has already paid off for you--you kept yourself from buying $200+ in chems from the pool store that you don't need--what we call being "pool-stored"!!!!

Since your pool was cloudy and went awhile without stabilizer, I would go ahead and shock the pool up to 15 ppm. I'm not sure what your pool volume is, but I'm assuming around 20K gallons. In a pool that size, each quart of 6% bleach will raise your FC by 1 ppm. You need to get to 15 ppm and hold it there by testing and adding whatever amount it takes to get back up to the 15--do this 2-3 times daily, or as often as you can. Leave it at 15 ppm until 1)the pool clears, 2)the CC goes to zero, and 3) you don't lose a any chlorine overnight when measuring after sundown and again before sun hits the pool in the morning. At this point you can let it drift back down to the 3-6 range and enjoy your pool.

As far aw whether to raise your CYA, that's a personal thing--I'd give it a week or so after you finish shocking the pool so you can get a feel for what your chlorine loss is going to be on a daily basis...if you're losing excessive amounts, then you can up the CYA a little and see if that helps.

You might try a paste of water and baking soda on the ring at your waterline. It won't hurt your pool chemistry and usually does a pretty good job of cleaning up vinyl liners. You may also find that after shocking the pool you don't see the ring anymore, either.

Hope this helps!!

Janet

Janet, thank you so much for the advice. I will shock tonight :)

Okay, I shocked with 3 1/2 gallons of walmart bleach. A test an hour later showed TC of 16, but still CC 0.5. I guess I thought that much bleach would kill anything that was lingering. I really expected a CC of 0. I will check in the am to figure out if I had an overnight chlorine loss and if the CC has finally been taken care of!

Tonight I realized that dirt is constantly entering the pool as my husband works on grading the surrounding area in preparation for concrete. Though I vacuum once or twice everyday, I wonder if that is impacting the CC or if it is that darn green ring around the pool.

I also realized that my tiny bottle of reagent isn't going to last long using 32 drops to test every time I shock!

Keep in mind that "shocking" isn't a one-time thing. You need to hold the water at shock level by testing and add more chlorine several times a day. If you shock it and let it just yo-yo up and down repetitively, you're not solving the problem. Chances are good that the dirt blowing in is contributing to your CC--try to keep it vacuumed as well as you can.

You can order more (and larger) reagents at several online sites--I usually get mine from spspools-spas.com but others have ordered from Amanto industries and like them. When you measure your chlorine, are you using the 25 ml sample, or the 10 ml? If you'll use the 10 ml sample, it doesn't take as many drops--you just multiply by 0.5 instead of 0.2.

Janet

Thanks for all your help Janet. I wish I was home more to baby the pool.

Last night:
FC 16
CC 0.5

This am (no direct sunlight on pool, but the sun had been up for about an hour):
FC 14
CC 0.5

Tonight:
FC 6.5
CC 0 (finally!!!!)

I just added 9 quarts of bleach tonight. I will retest in an hour or so and again in the morning. Hopefully we won't have a chlorine loss overnight. If the chlorine remains stable then should I just allow it to drop down to the appropriate maintenance level for my CYA? The water is sparkly and perfect. The green ring remains and it is feeling a tad bit slimy. I am going to hit it with a scrubby pad and baking soda over the weekend.

Thanks again, The Pool forum is the best :)

Ok last pm about 10 pm
FC 17
CC 0

This am
FC 15
CC less than .5 (it wasn't even pink, just not exactly clear either, cleared completely with 1 drop)

Water looks perfect. I will vacuum, backwash, and keep chlorine at 15 again tonight. What else should I be doing? Is CC a byproduct of using the pool? Should I be concerned that it keeps reappearing? Should I be concerned about the 2ppm overnight chlorine loss?

Thanks for all your help.

You don't necessarily need to backwash unless your filter pressure is 6-8 psi over your "clean" pressure. In fact, the dirtier sand often filters better than clean sand. However, if you're seeing a lot of pressure increase, then by all means backwash it. You might consider using skimmer socks, which can be found at most pool stores. It's just a fine mesh "sock" that fits inside the skimmer basket, like a coffee pot liner. You'd be amazed at how much stuff they catch that you don't even realize is in the water.

I wouldn't be concerned that the CC keeps reappearing....the CC indicates that the chlorine is working on something, and that's why we have it in there. People swimming in the pool introduce sweat, sunscreen, and other stuff we don't have to mention here ;) and your trees are introducing pollen and other stuff. So it's not unexpected to see CC appear and disappear--but you don't want them over 1.0. If it goes over 1.0, then it's time to shock the pool.

I am more concerned about the 2 ppm chlorine loss overnight--usually the rule of thumb is that if you lose less than 1 ppm overnight, then you can let the chlorine drift back down--but since yours is 2 ppm, AND you have residual CC, I'd let it stay at shock level another night and see what it looks like tomorrow.

Does brushing that green ring make any difference?

Janet