Free Chlorine Reading Zilch

[dalygnus]

Opened pool last Wednesday -- live in Northeast, 22,000 gallons 18x36 oval, vinyl liner, solid loop-loc cover removed -- put in 1 quart of algaecide 60, 3 lbs of shock after opening. Water didn't look too bad, just cloudy. In past years, 24-48 hours later, chemicals were balanced and water clear. This year, the pool took 5/6 days to clear and I have yet to get a free chlorine reading (the reading is not low, it's 0). I put 3 lbs of shock in each of the 1st 3 days -- put 6lbs in at once the 4th day -- and 3lbs twice on the 5th day -- still no free chlorine reading. Other readings (PH, alkalinity, stabilizer) are just about normal. I have had 6 3inch chlorine tabs (broken up) in the skimmer since opening. My pool store suggested that I continue to shock until I get a free chlorine reading. For some reason, all this shocking scares me. Is the pool god messing with me? Should I just keep shocking? It would be appreciated if anyone could offer advice or suggestions. Many thanks,
Jim

[Watermom]

Hi Jim and welcome to the forum! Do you have actual testing numbers taken with a drops-based testkit. If so, please post them. One of the numbers we will also need is a CYA reading. Also, tell us the ingredients of the shock you are using and tell us what type of algaecide you added. Then, somebody here can help you figure this out. One more question I just thought of --- what type of filter do you have and what size pump.

BTW -- If you don't have a good test kit, you should get one. We recommend the Taylor K-2006 or 2006C that can be ordered through the Amazon link in my signature. By doing it through this link, the Pool Forum makes a little money which helps keep this place online.

[dalygnus]

I have a Hayward filter 3/4 horsepower motor. My shock is poolbrand quick dissolving sodium dichloro triazinitrione. Algaecide 40 pool brand (sams club) dimethyl benzyl ammonium chloride. My tablets are pool brand 3 inch trichloro trianzinetrione. I also put in 2 lbs of cya 3 days ago. Pool store said my readings of cya were ok. I use the strips for testing but will invest in kit you mentioned for these problem times. Hope someone has some ideas. Many thanks.

[Watermom]

If you can, post an actual CYA reading. Also, any idea what the CYA was upon closing last year? Sometimes CYA is converted to ammonia over the winter which can cause a high chlorine demand upon opening. You just have to keep hitting it hard with bleach until your pool holds chlorine. We actually see many posters with this problem in the spring and they feel like they will never get enough chlorine in there to actually hold. Sometimes it can take gallons upon gallons upon gallons to the point where you think the problem will never rectify itself and then at some point it does. Keep shocking . It will eventually hold a FC reading. Keep us posted how things are going. And, don't worry about the strange looks you get at Walmart when you buy buggies full of bleach!

[dalygnus]

Thanks for the input. Just found out from my son that he also put about a quart of algaecide 40 in my pool during the opening (while I was out getting a part) -- so too much algaecide was probably used (which it seems is contributing to my problem). I've learned more about pool stuff in the last 24 hours at this site than I've discovered in 30 years of owning various pools. If I'm interpreting your input correctly you seem to be suggesting bleach as an inexpensive shock alternative. This has been a revelation for me and is clearly much less expensive than shock. I've ordered the test kit at Amazon so I will give you some readings when it arrives .... but I'm hopeful to have some FC reading before it gets here. Thanks again!

[Watermom]

Household bleach is usually 6% sodium hypochlorite and is what many of us use in our pools. It is the only thing I ever use. You can buy plain, unscented generic bleach and use it to shock with and as your daily source for chlorine. Hit is hard with bleach and you will eventually get that FC to stick. Keep us posted.

[CarlD]

OK. Do not use that algaecide any more. It's adding ammonia to your water which is making it hard for you to get an FC reading. You are fighting yourself. At the top, you said you put in a quart of 60 algaecide. If that was Polyquat, then, while it's a good preventative, it's only so-so at killing algaecide, and also makes it tough to get an FC reading (but it's more benign than ammonia).

With all the di-chlor ("shock") and the tri-chlor tabs, your CYA reading is very necessary, considering you added CYA as well. If it's gone too high you'll have to use only bleach/LC or Cal-Hypo (assuming your calcium level is low).

Carl

[dalygnus]

Started bleaching today with 2 gallons of 5.25% sodium hypochlorite. My wife who got in the pool and said the walls were slimy (water is clear). Would appreciate advice on maximum daily amounts of bleach (22,000 gallon pool capacity) and suggested frequency of application (e.g. 2 gallon every 4-6 hours, 8 hours, daily?). All the algaecide that was put in (about a half gallon) was algaecide 40 and the water is prone to foaminess -- so, I'm sure I did this to myself :-(

[CarlD]

Without a decent test kit it's very hard to maintain your pool. We suggest the K-2006 from Taylor. There's a link on Ben's and Watermom's signature to Amazon that helps support our site...and the price is competitive.

Generally, for a 20,000 gallon pool (close enough), 1 gallon of 6% adds 3ppm of free chlorine. 5.25% adds 2 5/8 ppm. 12.5% adds 6.25ppm.

The object of the exercise is to not have to add chlorine more than once every couple of days, but to do that, you need to have Cyanuric Acid in your pool, called CYA, Stabilizer, or Conditioner. This helps keep the chlorine from breaking down but slows down its processing as well. But the more stabilizer you have, the more chlorine you need in you pool as a base. We have something called the "Best Guess" table. Again, see Ben's sig for that (it's free).

You should check your chlorine and pH daily, and adjust them as needed. Your ideal chlorine level is determined by your CYA level. Generally we suggest CYA between 30 and 50ppm. But with the K2006, you can measure the CYA level, so that test should be done weekly, as well as the total alkalinity test, and, you should check calcium hardness once in a while (like twice a summer) with a vinyl pool to make sure the level isn't too high.

Carl

[aylad]

Started bleaching today with 2 gallons of 5.25% sodium hypochlorite. My wife who got in the pool and said the walls were slimy (water is clear). Would appreciate advice on maximum daily amounts of bleach (22,000 gallon pool capacity) and suggested frequency of application (e.g. 2 gallon every 4-6 hours, 8 hours, daily?). All the algaecide that was put in (about a half gallon) was algaecide 40 and the water is prone to foaminess -- so, I'm sure I did this to myself :-(

If you can find out a level for your CYA, then use the best guess chart in our sigs to determing what your target chlorine levels should be. All the levels posted here are safe for a vinyl liner pool. Until you can get your chlorine to register at all, you need to target the "shock" level, and add bleach as often as possible during the day to maintain that level until you're starting to hold a chlorine residual.

Janet