Chlorine Confused

[andersonsa]

I'm having trouble getting chlorine to stick around. I have an 18,311 gal vinyl inground. I have been using the dichlor/ trichlor tablets in a feeder for the last several years (before I found you guys!!)and created a huge CYA number, I have drained close to 1/2 the pool 3 times and have gotten it down to apr. 130ish. I have decided to live with it for a while. Been using Cal Hypo daily and it goes up but sun sucks it out thru the day. Being a pain to pre-mix so the powder doesn't go to bottom ans stain liner I recieved some good advice on switching over to bleach. Added bleach late evening yesterday and will check tonight. My numbers before I added were maybe 0 to a little over FC, 7.4 PH, 100 TA, apr. 130ish on CYA. I have standard OTO drop kit that only test TC but compare with some strips that check FC. According to pool math I needed 380 oz or so of 6% to get to the min of 10 on FC. I added 242oz of 8.25% bleach an I'll check again this afternoon. I have been a liitle concerned that I'm reading I need 10-16 on FC due to CYA being high when I also see out there that you should not swim if your level is over 5??? I'm confused??
Also, will it ever level out where I don't have to add bleach everyday. I was used to just setting the feeder and not having to add everyday.

Thanks in advance!!

 

[JasonLion]

You need to lower the CYA level down to something more reasonable and then SLAM the pool. You are not going to be able to get ahead of this problem with CYA that high.

The don't swim when FC is above 5 (or 3) is an old rule of thumb from before CYA existed. With CYA in the water the limit is much higher and depends on your CYA level.

 

[chem geek]

Welcome to TFP!

With a CYA of 130 ppm, the sun is not the primary source of your chlorine loss. I strongly suspect that you have nascent algae growth and that is consuming your chlorine. Once you get a proper test kit (which should be the first thing you do -- order the TFTestkits TF-100 or Taylor K-2006, the former having more of the reagents you need the most) then you can do an overnight chlorine loss test to confirm. Unfortunately, if you need to SLAM your pool to kill off the algae, it will take very high chlorine levels at your high CYA level. You should strongly consider doing another partial drain/refill to get the CYA even lower.

Ignore the advice that says you should not swim if the FC is over 5 ppm. With CYA in the water, most chlorine is bound to it and essentially inactive. It just holds chlorine until it is needed, but the active chlorine in the pool is very low, less than the equivalent of 0.1 ppm FC if there were no CYA. Even during a SLAM, it's equivalent to around 0.6 ppm FC with no CYA.

 

[RobbieH]

Are you diluting the pool water with tap water to get test results of 130? If you are running the test with 100% pool water, your CYA may be well over 130.

You should add bleach every day. There are ways around it, such as a Stenner pump, Liquidator, or salt water chlorine generator. Your convenience of those tablets have become a major inconvenience for you with this CYA problem.

 

[andersonsa]

Thanks for the advice and the info on the FC above 5. Will look at another partail drain soon.

- - - Updated - - -

Will be ordering a test kit this weekend. Could this algea be present even if the water looks fantastic??

 

[RobbieH]

The best way to know is to perform the overnight chlorine loss test.

http://www.troublefreepool.com/content/136-perform-the-overnight-fc-chlorine-loss-test-oclt

 

[andersonsa]

Hi, I have my Taylor K-2006 test kit on the way. However I decided to go ahead and start the slam just to see what numbers I am getting with the strips allthough I know they are not the best. I dumped 85-90 oz of Cal Hypo on Sat night but did not get my level test afterward. Tested before any sun got on the water Sunday morning and my FC was still around 0 according to the strips. Water did get cloudy but was clearing by Sunday afternoo. ( I assume this is to be expected??) I brushed and vacummed Sunday and dumped in another 90-110 oz and check 30 min later and the test strip almost immediatley went to the extreme for TC and FC. Tested this morning befor any Sun hit water and actully read 10-15 on FC. Finally a reading of FC the next day!!!! Would you recommend to do it again tonight? Lokking forward to the Taylor K-2006. Also, I'm new to TFP so I was not sure if this reply is o.k. or should I create a new post?

Thanks,

 

[duraleigh]

Keep your info under this thread. when your K-2006 gets in, post the new numbers but keep them under this thread.

 

[supermatt9]

Did your drain your pool anymore to get your CYA down? SLAMming is going to be difficult with it up that high.

 

[andersonsa]

Have not drained since I did the three 1/2 drains / refills (anymore and my liner wants to start floating on the shallow end) a week or so ago although lots of rain in the area causing me to pump out some and vacumming on waste and filling back up. Waiting on the k-2006 test kit to arrive to get a good CYA reading

 

[andersonsa]

Received the Taylor k-2006 yesterday. Ph-7.5 TA -129. Calcium - 250, FCC - 0, CC -0, CYA - 200 min. ( used the 50/50 advice from earlier posts). Due to some schedule conflicts it's going to be a week or before I can start the partial drain/ refill to lower the CYA. Did partial drains a week or so ago so I'm not how high the cya really was. Looks like I need to add 8 gal of liquid chlorine to get to proper shock level. Would anyone suggest that until I can start the drain process. Water is still pretty cloudy after adding the cal hypo last weekend. Also how many more times would one guess I'll need to repeat since I can only go a little less than 1/2 due to liner wanting to float.

Thank you,

 

[JasonLion]

There isn't really any value in adding chlorine now. Wait until you get CYA under 100.