Chlorine/pH maintenance issues

[webman3802]

We've had our pool for a couple of years now and I've always had trouble maintaining the chemistry, especially the chlorine level. I can add shock and we have a floater with capacity for four 3" tablets, which I usually keep topped off, but after a week, the chlorine test reads zero again, even with tablets still in the floater. I have to shock every week, not for extra sanitization, but just to maintain an adequate chlorine level. The chlorine levels dropping every week leads to green algae that so far I have been able to get clear each time, but it always comes back when the levels drop again.

Specs: we have an 18' x 52" Intex above-ground pool (~7000 gals) and the Krystal Clear 2100 Gph sand filter pump that came with it, set to run 12hr/day. I test chlorine and pH levels using a test kit with OTO and Phenol Red. I use the Chlorox brand products from Lowes: tablets, shock (XtraBlue), pH Up, and their green algae eliminator.

I've done my research and thought I'd ask for advice on the following questions:

• Any idea why my chlorine levels would be dropping so drastically in only a week's time and with tablets still in the floater? (The floater vents ARE open!)
• I have never been able to get my pH levels where they need to be, according to my test kit. It always reads an odd orange color that is somewhere between the yellow and pink comparison colors on the low end. Even adding pH Up does little to change the test reading.
• I have read that chlorine stabilizer products are unnecessary because the chlorine in shock and tablets is already UV stabilized. Is this true or is there some benefit to using a stabilizer?
• This is a pricier fix, but are salt water generator systems better at maintaining a consistent chlorine level? I've read about the pros and cons of each. Thoughts on this option? Intex or another brand (price is a factor)?
• Growing up, we only tested chlorine and pH levels, and so that's all I do now. Are other tests necessary or helpful in our situation (for homeowner, not a pool professional)? I want effective maintenance of clear, sanitary water, but some of these tests just seem to lead to unnecessary chemical additives. Also, thoughts on test strips for convenience vs the liquid chemical tests with the various drops?
• Finally, unrelated to the chemistry, is it a cost-effective improvement to upgrade to a higher capacity pump and sand filter? I've read reviews about the sand filter pump that came with our pool and it seems... just adequate.

Thanks in advance for any advice!

 

[Texas Splash]

Welcome to TFP! So your situation is not uncommon at all, and what you may be hearing/reading is vastly different that what we promote here at TFP based on many years of science, research, and proven reliability. So let's start with the following:
- A drop in FC is an indication of either too little CYA (stabilizer) to protect form the sun's UV, too much CYA from over-use of tablets (very possible now), lack of chlorine dosing, or excessive organics/algae. My guess it's the latter and also tied to a high CYA level..
- How are you testing your water? Which test kit specifically?
- We need to see a full set of "reliable' test results from a TF-100/Pro-Series test kit or Taylor K-2006C. Test strips or free local testing is of no value. They are horrible.
- Keep in mind that the pH and chlorine levels are two separate issues. The relationship of chlorine and CYA can be found on our FC/CYA Levels. PH is simply managed by muriatic acid when it exceeds 7.8 to help prevent scale.
- To confirm if your loss of chlorine is due to organics, we recommend you perform an Overnight Chlorine Loss Test with one of those test kits recommended above.
- In the future, sure, you can install a salt water generator to replace liquid chlorine or tablets, but no SWG can combat algae. To kill/remove excessive organics/algae, you'll need to implement the SLAM Process.

You can find much more info on our Pool Care Basics page, but in summary, everything you need help with begins with proper water testing at home. If you have any questions about this or anything else, don't hesitate to ask.

 

[CreedenceTapes]

We've had our pool for a couple of years now and I've always had trouble maintaining the chemistry, especially the chlorine level. I can add shock and we have a floater with capacity for four 3" tablets, which I usually keep topped off, but after a week, the chlorine test reads zero again, even with tablets still in the floater. I have to shock every week, not for extra sanitization, but just to maintain an adequate chlorine level. The chlorine levels dropping every week leads to green algae that so far I have been able to get clear each time, but it always comes back when the levels drop again.

Specs: we have an 18' x 52" Intex above-ground pool (~7000 gals) and the Krystal Clear 2100 Gph sand filter pump that came with it, set to run 12hr/day. I test chlorine and pH levels using a test kit with OTO and Phenol Red. I use the Chlorox brand products from Lowes: tablets, shock (XtraBlue), pH Up, and their green algae eliminator.

I've done my research and thought I'd ask for advice on the following questions:

• Any idea why my chlorine levels would be dropping so drastically in only a week's time and with tablets still in the floater? (The floater vents ARE open!)
• I have never been able to get my pH levels where they need to be, according to my test kit. It always reads an odd orange color that is somewhere between the yellow and pink comparison colors on the low end. Even adding pH Up does little to change the test reading.
• I have read that chlorine stabilizer products are unnecessary because the chlorine in shock and tablets is already UV stabilized. Is this true or is there some benefit to using a stabilizer?
• This is a pricier fix, but are salt water generator systems better at maintaining a consistent chlorine level? I've read about the pros and cons of each. Thoughts on this option? Intex or another brand (price is a factor)?
• Growing up, we only tested chlorine and pH levels, and so that's all I do now. Are other tests necessary or helpful in our situation (for homeowner, not a pool professional)? I want effective maintenance of clear, sanitary water, but some of these tests just seem to lead to unnecessary chemical additives. Also, thoughts on test strips for convenience vs the liquid chemical tests with the various drops?
• Finally, unrelated to the chemistry, is it a cost-effective improvement to upgrade to a higher capacity pump and sand filter? I've read reviews about the sand filter pump that came with our pool and it seems... just adequate.

Thanks in advance for any advice!

A word about chlorine tablets: They are best used only for short-term periods, despite what most of the industry would have you believe. Each trichlor (the most common form) tablet is about 52% cyanuric acid (also known as stabilizer) by weight. Cyanuric acid, in the right ratio to chlorine, is a good thing because it keeps the sun's UV rays from cooking off your chlorine too fast. The problem is, too much cyanuric acid has the effect of crippling free chlorine in your pool. And cyanuric acid hangs around in pool water much, much longer than chlorine does, so sooner or later most trichlor tablet users are going to have the problem of getting free chlorine readings that seem in range, but algae anyway because they've got too much cyanuric acid.

And just so you don't go looking for better tablets than trichlor, long-term use of any tablet is going to be problematic. Dichlor suffers from the exact same problem as trichlor, and calhypo tablets are eventually going to overload your water with calcium... also no bueno. Long-term, liquid chlorine or salt-water chlorine generators are the only way to fly. I'm #TeamLiquidChlorine all the way, but you'll rarely hear from anyone who has regretted moving to a SWCG.

As mentioned previously, to get a handle on things you need to have a reliable test kit. I have a Taylor K2006c, but TF Test Kits will also hook you up with a reliable kit. I typically get my refills from them. There's a very good chance that most of your issues are coming from having too much cyanuric acid in your water already, but you're not going to know for sure until you do some reliable testing on it.

As a parting note, you will rarely need to add anything to your pool other than liquid chlorine, muriatic acid, cyanuric acid, calcium chloride, salt (if you have a SWCG), and baking soda. Most additives like powdered shock, most algaecides, pH Down, and clarifiers, will put stuff in your water that will cause problems.

 

[webman3802]

Thank you both for the background info and I'll look into the information on this site in more detail.

I'll admit that I went cheap on our test kit and the reagents that came with it are at least 2-3 years old. Having said that, I don't mind paying for quality, but are there any brands of test kits that you'd recommend that are less expensive? $125 on sale is a lot to drop on a test kit as a homeowner. I understand the need for accurate results, just wondering if there's a less expensive but still decent quality option.

 

[Texas Splash]

just wondering if there's a less expensive but still decent quality option.

You could buy parts of the kit at a time, but in the long run you'll pay more later. The other issue is that with the water being suspect to algae, you need good-sized reagent bottles to supply all of the water testing you'll need to do should the SLAM Process be required. The small 5-way kits at the local store won't support that. I highly recommend TFTestkits.net, but by all means shop around. We don't' care where you get a good teat kit as long as you have one.

But take a look at the article below for more info.

Swimming Pool Test Kits Compared

What pool test kit should I buy? Why shouldn't I use test strips? Our recommended test kits will pay for themselves in no time!

www.troublefreepool.com

 

[CreedenceTapes]

Thank you both for the background info and I'll look into the information on this site in more detail.

I'll admit that I went cheap on our test kit and the reagents that came with it are at least 2-3 years old. Having said that, I don't mind paying for quality, but are there any brands of test kits that you'd recommend that are less expensive? $125 on sale is a lot to drop on a test kit as a homeowner. I understand the need for accurate results, just wondering if there's a less expensive but still decent quality option.

A good kit stings to buy. To numb the pain a little bit, know that you'll be saving money in the long run by not constantly buying other chemicals to fight your algae issues.

By the way, trichlor tablets also lower pH, so you'll likely be able to cut the pH Up from your routine when you quit using them. I'd be surprised to find that pH Up is not just expensively rebranded washing soda anyway*.

*It's actually less expensive from the prices I saw. So, contrary to my previous thinking, I'll be using Clorox pH Up for my laundry needs in the future instead of the other way around.

 

[duraleigh]

$125 on sale is a lot to drop on a test kit as a homeowner

I hear you. The test kits that we suggest have virtually ALL the tests that you need to maintain your pool using TFP methods. The chemistry is 100% warranted for one year from purchase and often you can go a bit longer than that but it's not guaranteed.

So, most folks here buy a refill set annually for about 50-60 bucks so your testing outlay drops in half your second year and stays there.

Secondly, it is really almost impossible to follow TFP advice and methods without one of these good kits.......the cheaper kits usually don't have the FAS/DPD test for chlorine which is the most important of all the tests.

It is a big leap but if you follow TFP methods, your pool can be crystal clear for years to come and you will not waste money on "miracle" ingredients the pool store will want you to buy. That said, TFP procedures will require a willingness to learn and precise testing.........you'll never regret your decision.

 

[webman3802]

Thanks for all the replies. You've convinced me (and more importantly, my wife! ) and I've ordered the test kit. I'll reply with results once it comes in.

 

[jconnpac]

Thanks for all the replies. You've convinced me (and more importantly, my wife! ) and I've ordered the test kit. I'll reply with results once it comes in.

I’m also new to TFP and I can tell you it was worth the $$$ for the right test kit. Pool is already looking clearer than ever and it’s helping me tweak my pH and Total alkalinity. As a bonus, our 9 yo grandson likes helping with the testing which helps me help him with math and he sees how cool chemistry can be.

 

[webman3802]

Thank you all for the insight. I did my testing tonight and, as you suspected, the CYA levels were off the scale. Like, way off. Looks like I will be draining some water and refilling to dilute it and switching to liquid chlorine instead of the tablets and powdered shock. My pH was also off the scale low, kind of a pale yellow color. I'll work on getting everything balanced after the dilution and the CYA level is where it needs to be. I did have a few questions about my chlorine and alkalinity tests, if you don't mind:

• FC tested at 7ppm. However, when I tried to test combined chlorine, the sample did not turn pink again when I added the 5 drops of R-003, suggesting no presence of combined chlorine. Is this right?
• I followed the instructions for the TA test, but when I added the R-008, the sample turned pink rather than green, so I was unable to continue to the next step. I read elsewhere in the testing book that CYA levels can affect TA, and since those are so high, can I assume that TA is untestable until CYA levels are brought in line?

 

[mknauss]

when I added the R-008, the sample turned pink rather than green

That means your TA is zero or below. Use baking soda to get the TA to 70 ppm. Add 30 ppm TA worth of baking soda at a time, let circulate for 30 minutes or so, and repeat.

 

[CreedenceTapes]

the sample did not turn pink again when I added the 5 drops of R-003, suggesting no presence of combined chlorine. Is this right?

Yes, that's right. There is more detailed information about the FAS-DPD procedures here, but I think you've gotten a reliable result.

 

[webman3802]

Thanks everyone for your help with all of this. It's definitely been a learning experience. I've drained about 2/3 of the pool and refilled, and CYA levels are now at 85. Still high, but at least they're on the measurable scale now. I'm going to let rainwater dilute it the rest of the way to recommended levels over time to save on the water bill. Switched to liquid chlorine and the other recommended chemicals and I've got everything balanced now and so far so good! We just had a little green which has cleared up now that FC levels are where they need to be, so looks like no need to SLAM for now. I'll keep an eye on levels and hopefully keep it clear this summer. So glad I found this site! You've got a convert.

One final question. We have a busy schedule and I know I will not be able to check chlorine levels daily, especially not with the full FAS-DPD process. For quick, convenient day-to-day testing, would it be okay to use test strips to get a ballpark of our chlorine level and top off as needed? I would still be testing using FAS-DPD at least weekly for more precise maintenance or as a diagnostic if the test strip results seem out of whack.

 

[mknauss]

Better to use the OTO yellow matching test. Get to know what shade of yellow sort of related to your FAS-DPD result.

Strips are not recommended for anything.

 

[CreedenceTapes]

Thanks everyone for your help with all of this. It's definitely been a learning experience. I've drained about 2/3 of the pool and refilled, and CYA levels are now at 85. Still high, but at least they're on the measurable scale now. I'm going to let rainwater dilute it the rest of the way to recommended levels over time to save on the water bill. Switched to liquid chlorine and the other recommended chemicals and I've got everything balanced now and so far so good! We just had a little green which has cleared up now that FC levels are where they need to be, so looks like no need to SLAM for now. I'll keep an eye on levels and hopefully keep it clear this summer. So glad I found this site! You've got a convert.

One final question. We have a busy schedule and I know I will not be able to check chlorine levels daily, especially not with the full FAS-DPD process. For quick, convenient day-to-day testing, would it be okay to use test strips to get a ballpark of our chlorine level and top off as needed? I would still be testing using FAS-DPD at least weekly for more precise maintenance or as a diagnostic if the test strip results seem out of whack.

In the rare event that I don't have time to test, I just add 4 ppm worth of chlorine. That number is based on the fact that, at my current CYA, that's the most day-to-day loss that I see. But then I don't mind running hot, and in fact, I intentionally do. The increased cost in chlorine and swim apparel is worth the peace of mind it brings me.

 

[duraleigh]

so looks like no need to SLAM for now

If you want to make that statement accurate, you need to perform an OCLT using the FAS/DPD chlorine test.

Post back if you need help with it.