First time pool owner - confused about chlorine levels

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R

rcarroll01

0
Jun 16, 2016
4
Mokena, Illinois
We recently bought a new home with an inground 16x35 vinyl liner pool. I am having a hard time keeping my chlorine levels right. The pool was extremely dirty when we opened it but now the water is clear and here are the latest water testing numbers.

TC 6.6
FC 1.3
PH 7.3
TA 100
CH 200
CYA 0

We shocked the pool twice at opening to clear the water. I have to add around 72 oz liquid shock every night to maintain a 1 FC level. I have a floating dispenser with 4 tabs of 3 inch chlorine in at all times but it doesn't seem to help. We are using a solar cover at night. The pool store is telling me to add 7 lbs of stabilizer and 12 lbs of power shock in order to lower the total chlorine, which seems like a lot of shock to add. We are having a party at the house in 3 days and I'm afraid we won't be able to use the pool if I add 12 lbs of power shock. What can I do to fix this problem?
 
Welcome to the forum! You will get great advice here and all the information you need to manage the pool. The process is predicated on accurate, self testing of your pool's water. To do this a proper test kit is required. I recommend the TF-100 but others use a K-2006. The TF-100 is about $70 but is something you wont regret. I can say it is a bit daunting to start out spending money, but pool store testing is just not accurate enough to be trusted. While you mull it over, consider how you want to manage your pool. Personally, I like knowing my pool and all the chemicals I add to it.

As for your results - CYA is the most critical and the most often missed by the pool store. If your CYA is zero, any free chlorine in the pool will quickly be burned off by the sun's UV rays. The liquid shock (bleach I hope) is good for now. That will help keep algae at bay, especially adding at night when the sun won't destroy it.

Send your questions and concerns and see where you end up. We would love another IL pool in the mix! Good luck.
 
Thank you for the reply. My test kit can't measure the CYA and the CH so those values are the pool store results. I will be purchasing one of the recommended test kits. In the meantime, can I not shock the pool for another 3 days or is the TC too high and needs to be adjusted now?
 
I do have some confidence that CYA is near zero - every year I open my pool after winter CYA is zero (side note - high CYA can cause a rash of issues and only option is water replacement). Assuming CYA of zero (at some risk), I would advise that you go to Wal-Mart or Lowes/Menards and buy some stabilizer/conditioner. Whatever it is called, you'll want enough to get you to 20. 20 is well below the recommended, but will buy you time until your kit arrives. The helpful links below will tell how to hang a sock in front of the return to add the CYA. Then buy some liquid shock (chlorine, bleach, its all the same), maybe 10-12 bottles. Wal-Mart has their 10% strength on sale for $2.50 a gallon now. And dose it to 10 ppm. That help with the elevated TC levels, really we are dealing with CC's - TC = FC + CC. Total chlorine = free chlorine (good stuff) + combined chlorine (this is basically the used up chlorine).

How deep is your pool, do you have an estimated volume in gallons?? You'll need to know this estimate CYA and FC additions in PoolMath.

Pool School - Chlorine / CYA Chart
Pool School - Test Kits Compared
Pool School - Recommended Pool Chemicals
Pool School - PoolMath
 
First...Welcome aboard!!

Now...Where did you get these test results (from reading the rest of your post, I assume the pool store)? It is tough to give you advice based on these figures because they don't quite make sense. If Total Chlorine is 6.6. and Free Chlorine is 1.3 that means your Combined Chloromines is over 5. This is the number you want lower, not the Total Chlorine. Another oddity is that you are using pucks, but have a -0- CYA level. Pucks will increase CYA. Puck also do not dissolve quick enough to increase Free Chlorine to a level that would address any organic issues. Finally, with your sized pool, 16' x 35' x (assumed avg. depth) 6', 72oz. of liquid Chlorine only raises FC by a maximum of 2.8ppm, and that assumes 12.5% concentration. This is also not high enough.

Unfortunately, it will be hard to help you with your exact issue without you doing your own testing with your own test kit (the TF-100 is linked in my signature. The Taylor k-2006 is also acceptable).

Can you add a signature to your posts? Include things like not only pool dimensions, but average depth, in ground or above, shape (this is important for pool volume.), type of filter and pump, accessories, etc.etc.

Given your short turnaround (3 days) and the fact that the test kit will likely arrive after the event, I would suggest (but would also appreciate some backup from an expert):

1. Remove the floating chlorinator.

2. Assume you have a CYA level of 20, use PoolMath to add enough Stabilizer to get yours to 40. Put it in a sock and put the sock in the skimmer. Every night give the sock a squeeze to release the dissolved stabilizer.

3. Add at least one jug (probably pushing upwards of 2) of 8.25% regular concentrated bleach per evening until the day of your party. If you have 12.5% concentration, add up to 1.5 gallons. The pool is safe to swim up to Shock level, which for a pool with CYA=40 is 16ppm. Even if your pool has no stabilizer as you have indicated, shock level at CYA=20 is 10 ppm. The amount of Chlorine you would be adding should not go over that, assuming your pool dimensions are accurate.

4. Watch your pH. As the stabilizer dissolves, your pH will decrease.

5. Once you receive your test kit. Run your own panel of tests.
 
Oh, I should have asked that. I would not add anymore then...yet! Your pool volume = 16 x 35 x (3+8/2) x 7.48 gallons/cubic foot = 23, 040 or 23,000 gallons. This is just a rough estimate, but a starting point. Using pool math, 3 lbs of CYA should have rasied your CYA to 16. This would not be easily detected by the pool store or the TF-100. Thanks for mentioning that!

Assume 20 CYA and I would add 2 gallons of chlorine. That should bring you to roughly 10 ppm FC, then I would add around 1 gallon a day until your kit arrives.

Anything else been added less the CYA and chlorine?
 
We just don't know, you say you have trichlor pucks in a feeder, which contain CYA, yet the test results show 0 CYA which makes them suspect, if correct it may indicate the that you have ammonia in your water from bacterial conversion over the winter. If so the solution is chlorine, in particular liquid chlorine added often and tested for often (every 20-30 minutes) until the FC level starts to hold better and the CC level diminishes. This assumes that the pool store has not sold you any other potions, in particular that they have not had you add any MPS Chlorine Free Shock which can show up on the test as CC.

Now since you are stuck in an impossible situation, I will tell you what I would try to do in your situation which will require some guess work, some blind faith and not a small amount of luck to be ready to swim on the weekend.

1, devote time to this, starting NOW, add ONLY liquid chlorine, and raise your FC level up to 9 ppm, assuming you have a DPD (pink color matching drops) test kit for Chlorine it will only read FC up to 5 ppm, so you will need to dilute your sample 50/50 with chlorine free water (rain water, distilled water, etc.) then multiply your test results by 2. Repeat every 15-20 minutes while scrubbing the pool. Since you have an unknown, but possibly low amount of CYA in the water, the best progress will likely be made after dark. So plan on staying up late tonight and continuing to pump the FC back up over 9 ppm anytime it drops below that, restock on liquid chlorine / plain household bleach (not scented , outdoor, or easy pour which all have additives) as needed, but keep that FC up there.

At some point in here you are likely going to need to change the DE in your filter, maybe more than once, Lowes sells that too in 20 pound boxes.

Once you get done maintain your FC at 3.5-4.0 ppm at all times until you get your reliable test kit in

p.s. ignore the dichlor part I just read about your initial 3 pounds CYA this makes the 0 reading even more questionable

p.p.s edited to remove refernce to dichlor and take into account your initial 3 pounds CYA and the potential CYA from your pucks, do you know how many you have used?
 

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It's hard to know what to say about the pH stabilizer. That could have been baking soda in an expensive package. CH doesn't matter much as long as it's above 50 ppm in a vinyl pool so that was unfortunate that the pool store told you that you needed to increase CH.
 
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