I will answer this question to the best of my ability

[frank1972]

Split off of this topic. Jason Lion

I read your problem regarding your ph rising I will answer this question to the best of my ability.
Ph will rise if you use powder chorine if you use chorine pucks it will lower ph. Weather temperature will affect ph with rain will dilute some but not a lot with a perfectly balanced pool.
Every time you use chorine this hill happen no matter how perfect your water balance. In hot months more acid because you use more chorine.
I would recommend using 1 type of chorine powder your Ta ideal is between 100 to 120
chorine pucks 80 to 100 ideal as for your chorine I would keep at 2 ppm to 3ppm no more no less if you use powder chorine you have more control you can test add 2 ounces of chorine on a ten k pool 1ppm if water is perfectly balanced I know it sounds strange but true. people tend to over treat their pool and cause damage all self inflicted. we always tend to give more then less human nature.Ideal ph is 7.6 to 7.4 remember this is a level that needs to be checked every 2 days to insure an ideal ideal ph period no way out if you want to have ideal ideal pool setting you have to test and test or if you want to have a balanced pool 7.2 to 7.8 test 2 times a week.
I hope I shed some light.

 

[jblizzle]

Re: Second season, pH still going up

Ph will rise if you use powder chorine

Not true. Dichlor or trichlor will lower the ph, Cal-hypo or liquid chlorine have no effect on the ph

I would recommend using 1 type of chorine powder your Ta ideal is between 100 to 120
chorine pucks 80 to 100 ideal as for your chorine I would keep at 2 ppm to 3ppm no more no less if you use powder chorine you have more control you can test add 2 ounces of chorine on a ten k pool 1ppm if water is perfectly balanced I know it sounds strange but true.

Here are the levels we recommend: pool-school/recommended_levels
Also 2-3ppm of chlorine is typically too low when the relationship with CYA is taken into account: pool-school/chlorine_cya_chart_shock

Please read Pool School to learn about the methods we teach as what you are saying is incorrect and contradictory.

 

[chem geek]

Re: Second season, pH still going up

One can readily distinguish between the cause of pH rise being from carbon dioxide outgassing vs. from plaster curing or dissolving or excess lye in bleach or chlorinating liquid because if the TA drops over time from adding acid then this is carbon dioxide outgassing. It's basically the TA lowering process. If the TA doesn't change much over time or if its rising, then it's more likely to be a chemical addition to the pool (from plaster or from the chlorine) that is causing the pH rise.

So this does sound like carbon dioxide outgassing in spite of the lower TA level. Other than further eliminating aeration or using a pool cover, you could add 50 ppm Borates which will reduce the frequency of your acid addition, though not the total amount of acid you have to add over time. Also remember that as seen in this chart, there is more outgassing at lower pH so don't try to lower the pH as much and instead let the pH settle in more at 7.7 to 7.8. The only issue for the higher pH would be if you have metals in the water; otherwise, with your lower TA a higher pH helps balance things out for the saturation index (the calcium hardness being the other factor).

 

[frank1972]

Re: Second season, pH still going up

I WILL TRY TO EXPLAIN MY ANSWER ON CHLORINE.
AVERAGE CHLORINE TEST KIT MEASURE .5 PPM TO 5 PPM THAT MOST HOME OWNERS WILL BUY.
IDEAL CHLORINE READING IS 2PPM TO 4 PPM
IDEAL CYA READING IS 30 TO 50 PPM
USING STABILIZED CHLORINE POWDER FOR EXAMPLE 10 K POOL 500 GLS WATER 1/2 OUNCE CHLORINE TO START POOL FROM SCRATCH AFTER BREAK POINT TO MAINTAIN IS BETWEEN 1 TO 2 OUNCE CHLORINE DEPENDING ON WEATHER AND BATHER LOADS. EXAMPLE APARTMENT COMPLEX MAYBE TEST 3 TIMES A DAY,WATER PARK MAYBE TEST EVERY HOUR DURING HEAVY BATHER LOAD RESIDENTIAL POOL MAY BE 3 TIMES A WEEK DEPENDING ON USE AND WEATHER HOT DAYS. IN OTHER WORDS TEST AND ADD ACCORDINGLY . NOT ADD ENOUGH SO YOU DONT HAVE TO TEST FOR A WEEK BECAUSE WATER LOOKS FINE.
TEST AND ADD SIMPLE FINAL ANWER .CYA IS A MOUTH FULL TOPIC CHLORINE PH AND SO ON.I AM TRYING TO KEEP IT SIMPLE.I AM ONLY TALKING ABOUT A BALANCED POOL.IF YOUR CYA IS HIGH YOU WILL PAY MUCH MORE TO OPERATE YOUR POOL SIMPLE .WHEN CYA TAKES OVER YOU WILL HAVE MORE CHANCE OF ALGEE OUT BREAKS AND POOL BALANCING ISUES YOU CANT SHOCK YOUR WAY OUT YOU WILL HAVE TO DRAIN PERIOD.HOME OWNERS WHEN THEY GET A POOL THEY ARE ADOPTING A CHILD IT NEEDS TO FEED A LITTLE AT TIME AND CLEANED IF YOU NEGLECT THE POOL IT DOSENT TURN RED IT TURNS GREEN. DONT OVER FEED THE POOL WITH CHLORINE AND ALL THE JUNK FOOD THEY SELL AT THE POOL STORE GIVE IT ONLY WHAT IT NEEDS. DEPENDING ON WHAT KIND OF PARENT YOU ARE TEST 7 TIMES OR 2 TIMES A WEEK UP TO YOU BUT REMEMBER ONLY ADD WHAT IT NEEDS NO MORE NO LESS.FINAL ANSWER. KEEPING HIGH LEVELS OF CHLORINE IN POOLS ITS NOT GOOD FOR YOUR HEALTH YOUR POOL EQUIPMENT AND YOUR POCKET BOOK.CYA IS A STABILIZER PART OF THE MIX DEAL WITH IT DONT RUN FROM A CHEMICAL BECAUSE NOT RESPECTED WILL CAUSE YOU A LOT OF PROBLEMS BALANCE YOUR POOL 90 PRESENT OF OWNING POOL IS PROPER WATER BALANCE THE REST CLEAN CLEAN PAY THE BILLS UNDERSTAND YOUR EQUIPMENT AND LAW TO PROTECT YOURS SELF AND FRIENDS AND FAMILY THAT USE YOUR POOL. FINAL ANSWER
NO MORE WHAT IFS 2PPM TO 4 PPM CHLORINE IN YOUR POOL CYA 30 TO 50 PPM IDEAL IF YOU RUN HIGHER COASTS YOU DONT USE CYA PRODUCTS REMEMBER IDEAL IS IDEAL UP TO YOU TO SEE WHAT TYPE OF PARENT YOU ARE.

 

[chem geek]

Re: Second season, pH still going up

Frank,

Welcome to TFP!

Please do not use all caps. It is very hard to read and is considered to be obnoxious and rude on forums.

Chlorine/CYA Relationship
You are new here and do not understand the relationship of chlorine to CYA which has been known definitively since at least 1974 as described technically in this paper. It makes no sense to give separate broad FC and CYA ranges as being ideal because it is the FC/CYA ratio that determines the amount of active chlorine that prevents algae growth, kills pathogens, and oxidizes bather waste. Some pools in southern climates with lots of direct sunlight may need higher CYA levels, especially when using saltwater chlorine generators, yet such pools are easily managed if the FC target is proportionately raised with the CYA level. See the Chlorine / CYA Chart for recommended FC levels at each CYA level. Also note that shocking is only done if needed and is not done regularly (i.e. not weekly). I didn't need to shock my pool at all the last few years.

As for high levels of chlorine not being good, you are correct if you are referring to the active chlorine level, but this is not the same as the Free Chlorine (FC) level. With CYA in the water, the active chlorine level is significantly reduced. 10 ppm FC with 100 ppm CYA has the same amount of active chlorine (hypochlorous acid) as 3 ppm FC with 30 ppm CYA and 0.1 ppm FC with no CYA so is a very low active chlorine level, far lower than most commercial/public indoor pools that do not use CYA.

Effects of Adding Different Sources of Chlorine
Though you describe the problems with high CYA, which as discussed is not an issue if the FC is proportionately increased, it is not clear whether you understand how CYA or CH increases with use of certain chlorine products. The following are chemical facts independent of concentration of product or of pool size:

For every 10 ppm Free Chlorine (FC) added by Trichlor, it also increases Cyanuric Acid (CYA) by 6 ppm.
For every 10 ppm FC added by Dichlor, it also increases CYA by 9 ppm.
For every 10 ppm FC added by Cal-Hypo, it also increases Calcium Hardness (CH) by at least 7 ppm.

So with a typical 2 ppm FC per day chlorine usage, use of Trichlor would increase the CYA level by over 35 ppm per month. If you do not proportionately raise your FC target as the CYA climbs, then algae can grow faster than chlorine can kill it. This is why many pools using Trichlor develop algae in the latter part of the swim season. You refer to "powder" chlorine, but are not specific as to which one. If Dichlor, then it will significantly increase CYA. If Cal-Hypo, then it will increase CH. If lithium hypochlorite, then this is very expensive.

As for the pH of chlorine sources, the hypochlorite sources of chlorine (bleach, chlorinating liquid, Cal-Hypo, lithium hypochlorite) raise the pH upon addition, but the pH drops back down as chlorine is used/consumed since the latter is an acidic process. This makes these chlorine sources close to pH neutral (except for a small amount of "excess lye" in some of them). Dichlor is close to pH neutral upon addition, but when the chlorine gets used/consumed, the pH drops so this source of chlorine is net acidic when accounting for such usage.

Measuring Higher FC and Other Water Parameters
As for measuring levels of chlorine higher than 5 ppm, the FAS-DPD chlorine test kit we recommend will measure up to 50 ppm and does so accurately with a "count the drops" technique. We recommend either the TFTestkits TF-100 or the Taylor K-2006 (a comparison of these kits is shown in this Pool School article. These test kits not only have the FAS-DPD chlorine test, but also measure pH, Total Alkalinity (TA), Calcium Hardness (CH) and Cyanuric Acid (CYA) and do so with far greater accuracy than test strips.

Ideal Total Alkalinity (TA) Level
As for the ideal Total Alkalinity (TA) level, this will be depend on the source of chlorine, but when using a hypochlorite source of chlorine, including bleach or chlorinating liquid, one wants the TA level to be on the lower side, usually not above 80 ppm, since pools are intentionally over-carbonated to provide a pH buffer and to saturate the water with calcium carbonate to protect plaster surfaces. Such over-carbonation leads to carbon dioxide outgassing that causes the pH to rise. So the TA needs to be lower when not using net acidic sources of chlorine (or other chemicals).

 

[frank1972]

Re: Second season, pH still going up

Im sorry about the caps was not trying to be rude. I am not trying to change facts on chlorine or cya the information has been around since the dinosaurs roomed the earth.
if people are going to use bleach or chlorine from the pool store cya will rise using a stabilized chlorine (we know this)in time if you balance the water chemicals maintain a Fc reading 2 to 4 ppm start with a cya reading say 30 ppm it may take 1 year 6 months to reach 100 or 2 years depending on use weather , bather loads many factors I have no doubt you will do a partial drain at some point thats the way it was designed..... I have no problem with using bleach to maintain a pool but in behalf of the rest of the world I am saying that using the proper amounts of chlorine per treatment don't shock the pool to shock the pool add a cup shock and puck chlorine because your neighbor does. If you use bleach what ever you want to put in your pool as long you use a proper sanitizer. For example one 40 pound bucket of Dichlor chlorine properly added DOSAGE to the water will last 16 months before cya will reach a 100 ppm no other shocks just proper dosage region say south east every year. No You can control the chemicals but you cant control weather. Thats a fact. I have no idea where you want to go with topic answer chemical use, weather , human error and water usage I don't have a crystal ball. Sorry.
if you can maintain a cya 80 ppm before you start having problems with water quality or 100 does not matter 90% all pools in us are running incorrect because lack of education. I think to many know it alls try to pass a pill for a simple solution in this industry final answer weather human error use of pool.

 

[chem geek]

Re: Second season, pH still going up

For example one 40 pound bucket of Dichlor chlorine properly added DOSAGE to the water will last 16 months before cya will reach a 100 ppm no other shocks just proper dosage region say south east every year. No You can control the chemicals but you cant control weather. Thats a fact.

That is absolutely positively not true that use of Dichlor will take so long to build up 100 ppm CYA, at least if this is the primary source of chlorine. As I wrote, for every 10 ppm Free Chlorine (FC) added by Dichlor, it also increases CYA by 9 ppm. So if you start with 30 ppm CYA in your pool, you will get to 100 ppm (70 ppm higher) after cumulatively adding 70/.91 = 77 ppm FC from Dichlor. If daily chlorine usage is 2 ppm FC, mostly from breakdown from the UV in sunlight, then this is only 39 days of Dichlor use. Even if the daily FC usage was only 1 ppm, then it's 77 days of Dichlor use. Not 16 months. This assumes, of course, that there is not significant water dilution, but even backwashing sand filters is not enough dilution to keep things in check, though huge summer rains might, at least for one season.

Furthermore, a 40 pound bucket of Dichlor in 15,000 gallons would be 180 ppm FC so would only last for 90 days (3 months) if 2 ppm FC per day. If you are talking about a 7500 gallon pool, then that's 360 ppm FC so 180 days (6 months) at 2 ppm FC per day.

I presume you must be talking about using the Dichlor on occasion only, and not for daily chlorination. Even so, that 40 pound bucket in 15,000 gallons would increase CYA by 164 ppm if there were no water dilution. If this were a 7500 gallon pool, then the CYA would increase by 328 ppm.

This is why we generally say to use chlorinating liquid or bleach as your primary source of chlorine. You can use Trichlor pucks/tabs or even Dichlor on occasion if your CYA level is dropping or you can use Trichlor briefly if on vacation knowing that the CYA will rise during its use.