New pool, 2 tests, 2 different results

Cmcgrew

Member
Jul 31, 2020
10
Kingwood, TX
Hello!
I am brand new to pool ownership and am trying to learn the ins and outs and figure out what to do to keep our awesome pool running well! This is a long question so I apologize.

I read a lot here before moving into the new house and was concerned about CYA since I found out our new pool has an automatic chlorine table dispenser thing, and the tablets add CYA to the water until it is so high you have to drain part of the water to get it back down. We decided to go ahead and use the tablets we have and then decide if we wanted to move to liquid Chlorine.

I tested the water with my new Taylor k6000 kit and I'm sure I didn't do it right. So we took our water to Pinch a Penny pool store and they did a free analysis. They said our water is PERFECT....
But then I looked at the numbers and inputed them into Pool Math to make sure it was all recorded.
Here are the levels from Pinch a Penny:
Total Chlorine: 3.0 ppm
Free Chlorine: 3.0 ppm
Combined Chloring: 0 ppm
pH: 7.4
Alkalinity: 100 ppm
Calcium Hardness: 275 ppm
Stabalizer (CYA right?): 100 ppm !!!! This is super high right??
Dissolved solids: 400 ppm

So when I put it into pool math, it is telling me to do all sorts of things...including draining the pool to decrease CYA, adding 466 oz of calcium Chloride and 54oz of Borax.

Why is Pinch a Penny saying I have 'perfect water' but pool math recommending all sorts of intervention? ...I assume it is because the CYA is so high. So my actual question is, how urgent is it for me to get the CYA down? Will that fix the other problems? My husband is feeling like we should just leave well enough alone. The water is clear and beautiful and seems perfect...but I don't want to neglect something and then have bigger problems.

Thank you so much for any help you can give me!
Courtney McGrew
 

YippeeSkippy

Mod Squad
LifeTime Supporter
Jan 17, 2012
14,819
Evans, Georgia
Hi there Courtney, welcome to TFP :wave:

Why don't you trust YOUR K-2006 test kit results? What were they?

Did you use the PoolMath App or the web version found below? How did you choose what your target level was that you desired?

Yes, 100ppm CYA is too high. The problem with that result is that the test kit only reads up to 100. You might be far higher. SO the way to test that is to mix *equal parts of pool water and tap water* and use that as your pool water sample and re-do the test, but double the result.
Make sure the sun is to your back and hold the vial waist high..... don't stare hard, just glance back and forth at the vial for the dot.

Let us know all YOUR test results ;)

Maddie
 

rumcglot

Silver Supporter
Feb 13, 2019
95
Texas
What is the k6000 kit? Did you mean k2006?

You should post your test results. This forum isn't a fan of store testing. You, yourself, have already become too educated to believe their advice. :) So you already know the answer to your question... they don't know how to interpret their results.

The ever higher CYA will lead to ever higher amounts of chlorine needed to maintain the pool. The sooner you can get the CYA down the sooner you'll have a more easy to manage pool. I don't think it is urgent if the pool is doing OK, but you should seek a convenient time to drain in the not-too-distant future.

I'm not sure why Pool Math said to add the other things. It seems odd.

Be sure to read the Pool School article on draining or exchanging water for techniques.
 
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DorsalSpine

Gold Supporter
Silver Supporter
Jul 8, 2013
714
Columbus, Ohio
The CYA test can be fairly difficult. However, if yours is really 100 or higher the test is easier because the dot disappears quickly. One of those tests that if it is easy to do you are not going to like the result. You need to test yourself with straight pool water and diluted pool water to get a good number. An FC of 3 with the correct level of CYA is okay. Your pool store is behind the time and doesn't understand the relationship between CYA and FC. At your level your CYA is so high that your FC is not doing its job. You run the risk of a pool that isn't sanitary and if you do get algae it is almost impossible to treat.

I have had to deal with clear looking water and a CYA of 200 plus. You need to get on top of it before it becomes a bigger problem. It is easier to fix now while the water is clear. Either way if it is that high you need to plan on exchanging water at some point. CYA doesn't go away and the only solution is some form of removing water and adding new water. Not what I wanted to hear when I was in your shoes but after I heard it enough I finally bit the bullet and replaced water.

There are a lot of good people here who will be happy to help you enjoy your pool. You might read the Pool School articles to get a better understanding of how it all works. With the good advice I received here I'm coming up on ten years of perfect water every year.
 

Chasarms

Silver Supporter
May 8, 2020
347
Dardenne Prairie, MO
If you are using trichlor pucks in the Rainbow, CYA levels are going to continue to rise.

I assume you just bought the house and the pool came along? The previous owner was likely using the inline feeder to chlorinate.
 

Cmcgrew

Member
Jul 31, 2020
10
Kingwood, TX
What is the k6000 kit? Did you mean k2006?

You should post your test results. This forum isn't a fan of store testing. You, yourself, have already become too educated to believe their advice. :) So you already know the answer to your question... they don't know how to interrupt their results.

The ever higher CYA will lead to ever higher amounts of chlorine needed to maintain the pool. The sooner you can get the CYA down the sooner you'll have a more easy to manage pool. I don't think it is urgent if the pool is doing OK, but you should seek a convenient time to drain in the not-too-distant future.

I'm not sure why Pool Math said to add the other things. It seems odd.

Be sure to read the Pool School article on draining or exchanging water for techniques.
Yes, sorry...I mean k2006. Sorry... 😂
 

Cmcgrew

Member
Jul 31, 2020
10
Kingwood, TX
Thank you all. That is great advice. I figured I would need to remove water and ignore the pool store advice. I'll post my results soon.

Also, we got a HUGE rain last night. The water level is super high right now. I am looking forward to seeing if that affected the cya level at all.
 

BowserB

Silver Supporter
Jul 29, 2018
363
Katy, Texas
Hi Courtney, from someone else in the greater Houston metro area--Katy. I'm no expert, but 3ppm chlorine at 100ppm CYA is a long way from perfect. If you look in the pool school, you'll see a CYA-Chlorine chart. At CYA of 100, the minimum free chlorine level is 8 ppm, and recommended is 11-13 ppm, so right now you are at risk for an algae attack!. I would hurry and get some liquid chlorine and stop using the tabs. I've shopped everywhere in the Houston area for the best deal on chlorine, and amazingly enough, the best price I've found for 12.5% liquid chlorine is a nearby Leslies. $16.99 for a box of four 1-gallon jugs. You may find a gallon of chlorine cheaper at Walmart, but it is 10%, and when you compare with 12.5%, I see Leslies is cheaper--plus you can pull right up to the door at Leslies and not have to go to Walmart. Be careful of supermarket chlorine with additives and low chlorine content. I see "Concentrated" at HEB--and it's only 6%. Yes, putting a bunch of liquid chlorine into the pool now will be partly wasted when you dump water into the storm drain, but better to waste a few dollars worth of chlorine than to spend many dollars and time fighting algae!
 

HermanTX

Gold Supporter
May 20, 2020
774
Katy TX
To follow up what Bill said regarding liquid chlorine, I have found 3 places that offer best bang for $$. Leslie's has the 12.5%, Home Depot has 10% and pinch a penny has 10.5% (but only sells in 2.5 gal jugs that are returnable to refill (like propane gas for BBQ). If you put all of this in Pool Math "Bleach $ Calculator" the Pinch a Penny is slightly cheaper and Home Depot & Leslie's are almost identical in net cost. At Home Depot you need to watch the mfg. date as sometimes it can sit on shelf a while. On Leslie's product I cannot find a mfg. date on the box or jug and Pinch A Penny fills the 2.5 gal jugs from a large tank which is filled weekly (at least that is what I was told). So now you have my investigation for liquid chlorine in the Katy area.
 

HermanTX

Gold Supporter
May 20, 2020
774
Katy TX
Thank you all. That is great advice. I figured I would need to remove water and ignore the pool store advice. I'll post my results soon.

Also, we got a HUGE rain last night. The water level is super high right now. I am looking forward to seeing if that affected the cya level at all.
Take note of the earlier comment on using rain as replenishment. If it predicts heavy rains then drain several inches (maybe close valve to skimmer suction) and circulate only using bottom drain. Then let the rain fill it up.
 

Dtkokay

Well-known member
Dec 31, 2019
313
Houston, Texas
To reiterate, the minimum FC level needs to be increased as your CYA increases. Because your CYA might be high, your FC needs to be way more than 3 ppm. Check the FC / CYA table under the ABCs pool school section of this web site.

CYA protects chlorine, but it also prevents part of the chlorine from being used to sanitize. That’s why FC needs to increase as your CYA increases.
 

Cmcgrew

Member
Jul 31, 2020
10
Kingwood, TX
I will read up on all that and plan to drain the pool a bit very soon. I am going to redo my tests this afternoon and I'll post my results. I really appreciate all your help!
 

DorsalSpine

Gold Supporter
Silver Supporter
Jul 8, 2013
714
Columbus, Ohio
Remember that CYA stays with with water. Several inches of rain added to the existing pool water will not dilute your CYA much at all. Draining the water down prior to the rain and adding several inches of new water is more effective.
 

Cmcgrew

Member
Jul 31, 2020
10
Kingwood, TX
Okay, I just did a test. Here is what I got:
Free chlorine: 4.2 ppm
Combined chlorine: .2
pH:7.3
TA: 80
CH: 170
CYA: More than 100

I know that draining some of 9ur pool and refilling is in our future. What else will I need to do? Feeling a bit overwhelmed. I will be reading up on all this, but any advice is so appreciated.

Thank you!
 

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CrystalRiver

Well-known member
Jun 19, 2020
308
Massachusetts
Step 1: Get liquid chlorine and add it to your pool ASAP, to prevent a major algae outbreak. Use Pool Math to calculate the dosage.

Step 2: Do the diluted CYA test to figure out what your CYA actually is. You need this info to calculate how much of your pool you need to drain.

Don't worry about any of the other tests for now. There's no point if you're about to drain 3/4 of your pool.
 

magiteck

Gold Supporter
May 20, 2020
192
Neenah, Wisconsin
Okay, I just did a test. Here is what I got:
Free chlorine: 4.2 ppm
Combined chlorine: .2
pH:7.3
TA: 80
CH: 170
CYA: More than 100

I know that draining some of 9ur pool and refilling is in our future. What else will I need to do? Feeling a bit overwhelmed. I will be reading up on all this, but any advice is so appreciated.

Thank you!
Since the CYA test maxes out at 100, you can do a diluted test to get a more accurate reading so we can see how far over 100 you are.

For the sample, use 1/2 tap water and 1/2 pool water. Since tap water has no CYA we know that you’ve now cut the CYA level in half.

Test the CYA level of the diluted sample. When you get the result, then we’ll multiply that by 2. So if for example the diluted test measures 80, we call your CYA 160.

That will give you a better idea of how much water needs to be replaced.
 

Cmcgrew

Member
Jul 31, 2020
10
Kingwood, TX
This may be a dumb question....When draining and adding city water, is it possible to do both at the same time...meaning can I drain to waste while having the pool filler turned on? ....or would that not have the same impact? I'm just wondering about maybe doing that a bit each day, testing the water each day until I get the cya down to an acceptable level? (And adding liquid chlorine as I go.)

Also, do people who use liquid chlorine only have to add chlorine every day?
 

CrystalRiver

Well-known member
Jun 19, 2020
308
Massachusetts
Simultaneous drain and fill is possible. Sometimes it's necessary. But it's the least efficient method in terms of water use. As you are pumping out, you won't be pumping only your high-CYA water, but some of your fill water will mix in and get pumped out, too.

Typical is daily chlorine and some acid once or twice a week.
 

HermanTX

Gold Supporter
May 20, 2020
774
Katy TX
First of all, there is no dumb question on the forum. Everyone is learning something new everyday.
Yes you can drain and replace at the same time. It is not as effective as a drain and refill but there are some things you can do to make it work. There is a Drain Procedure on the forum - look in Pool School. First, do you have a bottom drain? Can you control suction (with a valve) between your main drain and skimmer? Maybe post a picture of your equipment pad at different angles.

I have done this before and my process was, put the the return suction only on the skimmers (shut off main drain), brush the pool sides and steps. Set your output to WASTE or DRAIN (not filter) Put on pump and let it drain the 2-3 inches until the skimmer is just about uncovered - don't suck air into your pump - so you need to watch this very carefully. Turn on your water to fill your pool. Now switch your valve from suction from skimmer to suction only from the bottom drain. Turn on pump and monitor your flow. If you are draining the pool faster than what you are filling then turn off your pump for a while, then restart. It is not a perfect solution but allows you to remove "mostly water with CYA in it" while adding fresh water without exposing your plaster to the hot sun. Ideally you would want to use an external pump (not your filter pump) but if that is not feasible you can do it with your filter pump.

I do use liquid chlorine and I do add some everyday due to the hot sun. I only use the 3" pucks if I go out of town for a weekend.
Keep us informed.