Chart For Pool Chemistry Ideal Ranges?

[Snowymoon]

Is there a sticky or chart around with all the pool chemistry ideal ranges? If not, it would be convenient to find one here. I don't know enough to make one. In fact, I am refreshing my brain for this year's pool (have an Intex that we take down each fall), and I can't remember much. :lol:

On that note, I am so grateful this site is here.

 

[JohnT]

There could probably be a guideline summary made, but it's a little more complicated than a chart. For example: 3ppm chlorine is fine with 20ppm CYA, but if your CYA is 100ppm, 3ppm chlorine is too low. Other readings interact, and recommended levels change with pool type and whether you have a heater.

 

[Snowymoon]

I see. Thank you so much. I think I have found what I need. :-D

 

[NWMNMom]

I'm guessing that a general GENERALLY or EXCEPT AS FOLLOWS statement could work for most of us though. A lot of the drops test kits have range charts with the exceptions notes at the bottom, that would probably work. Kind of like the WNL (within normal limits) range charts for height and weight of our kids - thank goodness our pools are less complicated than the kids. Can we can we PLEASE??????

 

[DavidD]

With an Intex 18-foot, inflatable-ring pool, I'd recommend the following:

FC (Free Chlorine)- Based on your CYA (Stabilizer) levels as follows:

Ben Powell's 'best guess' FC/Stabilizer table for algae free operation of OUTDOOR pools
-- as of July 2003 --

CYA-Stabilizer . . . . . . Min. FC . . . . Max FC . . . 'Shock' FC
=> 0 ppm . . . . . . . 1 ppm . . . . . 3 ppm . . . . 10 ppm
=> 10 - 20 ppm . . . . 2 ppm . . . . . 5 ppm . . . . 12 ppm
=> 30 - 50 ppm . . . . 3 ppm . . . . . 6 ppm . . . . 15 ppm
=> 60 - 90 ppm . . . . 5 ppm . . . . . 10 ppm . . .. 20 ppm
=> 100 - 200 ppm . . . 8 ppm . . . . . 15 ppm . . .. 25 ppm
credit Pool Forum/Ben Powell

pH- 7.4 to 7.8

Alk (Alkalinity)- 80 to 120 ppm

CH (Calcium Hardness)- Really irrelevant in your pool but anywhere between 0ppm to 450 ppm is fine

CYA (Stabilizer)- 30 - 50 ppm is ideal for most and I highly recommend not letting it get above 90ppm

Hope this helps.

Dave

 

[JasonLion]

There are just so many exceptions.

FC can be lower than the best guess chart with a SWG. No once seems to be sure just how much lower you can go, but clearly it is at least a little lower.

With bleach or a SWG it is better to have ALK around 80 to 90 and with trichlor pucks it is better to have ALK around 120.

With a plaster pool CH should be between 200 and 400.

If you get many many hours of direct sunlight every day or are using a SWG then CYA should be 60-80. Check your SWG manual for your manufacturers recommendations here, some of them suggest/require different levels.

Some people run with higher PH, 7.8 or even 8. This can be simpler to take care of once you have the system down but requires a whole different approach to a couple of things.

If you have a metals problem then keep PH on the low side, 7.3 to 7.5.

If your pool really really likes some particular PH and ALK, and they aren't way out of range, it is often best to let it have it's way.

 

[DavidD]

.....With bleach or a SWG it is better to have ALK around 80 to 90 and with trichlor pucks it is better to have ALK around 120....

I've never heard that before. I'd say with Tri-chlor a higher Alk might make sense, again depending on a host of other circumstances but lower purely because of Bleach does not.

.....If you get many many hours of direct sunlight every day or are using a SWG then CYA should be 60-80....

I would not recommend starting with a CYA this high no matter how much sunlight you get however there are others who prefer running higher CYA levels but they maintain higher FC levels to compensate. As for Jason's other references to SWG's and gunite/Plaster pools, I agree on on the levels he has posted.

AS Jason points out, there are a bunch of "ifs" but again, with an Intex 18-foot, inflatable-ring pool, SWG's, CH and metals are no concern and you shouldn't worry about them.

Dave




.

 

[JasonLion]

I think of 80-90 as the default for ALK. Trichlor pucks are constantly lowering the PH so you want to maintain a higher ALK to keep that effect under control, thus ALK 120. Also, a SWG tends to raise PH more quickly the higher the ALK, so keeping ALK low is an advantage there. With bleach it doesn't mater as much, PH tends to stay stabe, so I go with the lower number so there are fewer chemicals to add.

 

[DavidD]

I think of 80-90 as the default for ALK. Trichlor pucks are constantly lowering the PH so you want to maintain a higher ALK to keep that effect under control, thus ALK 120. Also, a SWG tends to raise PH more quickly the higher the ALK, so keeping ALK low is an advantage there. With bleach it doesn't mater as much, PH tends to stay stabe, so I go with the lower number so there are fewer chemicals to add.

The default is 80-120 ppm for Alk by most, if not all published standards. Most test kits aren't that precise and have variances greater than one increment (10 ppm for most residential Alk tests) so if Snowymoon were to target say 100 ppm for Alk, she'd have some leeway for the test's tolerance.
Keeping a lower Alk with both SWG's and fiberglass pools does make sense, just not in this instance. I have found it is better to err on the side of low Alk as it is much easier to add than to lower.

Dave

P.S.-Can you tell I'm bored this afternoon since I/m hanging about?

 

[Snowymoon]

Thanks everyone. :-D I appreciate all the replies.

The only problem I have had with my pool water is very high pH and TA (filled with well water each year; oh, how I wish I could close the pool and just leave it up instead). The TA is so darn high, I never actually got it in range after working on it practically all summer last year. By the time I found the information on how to do it properly with aeration, it was late in the season. It was time to drain and take down the pool before it got in range. :? I am hoping for better luck this year.

I also hope that is pollen I see in the bottom of the pool as it is filling (takes a couple days) and not mustard algae.

 

[KurtV]

Snowy,
If you're taking the pool down at the end of every season, why worry about the TA? Seriously, high alk is only an issue if it's going to cause scaling. Not knowing the rest of your chemistry I can't say whether that's likely or not over the course of a few months, but if it isn't, keep your pH and chlorine levels in line and enjoy the pool.

 

[Guest]

.....With bleach or a SWG it is better to have ALK around 80 to 90 and with trichlor pucks it is better to have ALK around 120....

I've never heard that before. I'd say with Tri-chlor a higher Alk might make sense, again depending on a host of other circumstances but lower purely because of Bleach does not.

Dave

.

Actually, the published TA ranges in the recent CPO study manual recommends a TA of 100-120 for stabilized chlorine (since it is acidic and reaction of hypochlorous acid when it sanitizes and is reduced to chloride ions is acidic so the net effect of stablized chlorine is acidic) and a recommened 80-100 for unstablized chlorine, including bleach, because the unstablized chlorines are alkaline and the same acidic reaction takes place when they get used up by sanitizing so the net pH effect from them is fairly neutral. By keeping the TA lower the pH won't have as much as a tendency to climb (The main effect of the carbonate buffer system is to cause the pH to rise toward 8.2) and the acid usage will be lower. It makes perfect sense. Since SWGs produce unstabilized chlorine the lower TA will lead to more stable pH with them also.

 

[Snowymoon]

Snowy,
If you're taking the pool down at the end of every season, why worry about the TA? Seriously, high alk is only an issue if it's going to cause scaling. Not knowing the rest of your chemistry I can't say whether that's likely or not over the course of a few months, but if it isn't, keep your pH and chlorine levels in line and enjoy the pool.

Are you serious? Would that be okay to do that? I wish I could leave the pool up all year long and just close it, but I don't think that is possible with the type of pool I have (blow-up-ring Intex) and where I live (upper mid west).

 

[KurtV]

Are you serious? Would that be okay to do that? I wish I could leave the pool up all year long and just close it, but I don't think that is possible with the type of pool I have (blow-up-ring Intex) and where I live (upper mid west).

Another downside of super-high TA that I didn't mention is that your pH will likely rise rather rapidly. This will require frequent acid additions. If you can live with that and your calcium hardness isn't too high you can probably leave TA alone.

What are your numbers; particularly calcium hardness, TA, and pH?

 

[Snowymoon]

I am not done filling yet, so I have not run all the tests, but the TA is always off the chart on the strip tests. Can't remember what I got on the drop test last year. The pH is always off the chart on the strip tests too, well above 8.4. I have not done drip test yet. The weird thing is the calcium level is zero. Zero! Could all this alkalinity and high pH be magnesium/lime? There are metals or other nasties in the water (fill with well water).

As soon as it is full later, I will post full test numbers.

 

[JohnT]

I am not done filling yet, so I have not run all the tests, but the TA is always off the chart on the strip tests. Can't remember what I got on the drop test last year. The pH is always off the chart on the strip tests too, well above 8.4. I have not done drip test yet. The weird thing is the calcium level is zero. Zero! Could all this alkalinity and high pH be magnesium/lime? There are metals or other nasties in the water (fill with well water).

As soon as it is full later, I will post full test numbers.

If it was lime, your CH would be high. Our well water is the same. Very high TA (480+) from carbonates of sodium and low CH.

 

[KurtV]

I am not done filling yet, so I have not run all the tests, but the TA is always off the chart on the strip tests. Can't remember what I got on the drop test last year. The pH is always off the chart on the strip tests too, well above 8.4. I have not done drip test yet. The weird thing is the calcium level is zero. Zero! Could all this alkalinity and high pH be magnesium/lime? There are metals or other nasties in the water (fill with well water).

As soon as it is full later, I will post full test numbers.

Well if your CH is near zero, I don't think running your pool with the high TA will present any problems in the short term (ie. one season). Just keep the chlorine level per the Best Guess chart and the pH between 7.2 and 7.8 and I think you'll be fine. As I said before, you'll probably have to add acid frequently but you won' use anymore than you would in lowering the TA.

I know I'd much prefer to add acid every two or three days than go through two or three weeks or more of the alkalinity reducing procedure.

 

[NWMNMom]

My Alk runs high most years as well (180-200) but we seem to be able to keep our PH within a good range almost all the time (7.2-7.4) We only seemed to have more of a problem this year when more salt was added, (we run 120# salt in our pool each year - no SWG) we noticed the PH creeped up to 7.8 or so and we have gotten some minimal cloudy issues. DH didn't notice it but I did - he thinks I imagined it. I'm particular about my nice clear water.

Is this coincidental? I know that the additional salt this year just happened to be around the same time we got deluged with all the rain (total rain pumped OUT so far in 2 weeks is 10.5") Makes it hard to keep up with the chlorine too - rain in, pump out, add more bleach to get back to levels needed.

 

[chem geek]

Rain makes a great aerator -- lots of splashing drops over the entire surface area of the pool over an extended period of time. I would bet that this was the cause of the pH rise (along with high TA, of course). If your pH stabilizes after the rain stops, then it was the rain and not the salt that was the cause.

 

[NWMNMom]

Did I misunderstand somewhere, but doesn't aeration lower the Alk? Would rainwater be high in alkalinity and raise PH? I'm hoping this is the answer. Even with my usually somewhat higher Alk, I have never before had big problems with my PH going up, Alk going up or cloudy water - but then we have never had this much rain in 2 weeks since I can remember. YIKES. We could have just as well started swimming in the yard there is so much water.