Become a TFP Supporter Pool Math Forum Rules Pool School
Page 1 of 2 12 LastLast
Results 1 to 20 of 40

Thread: (NOT URGENT :) ) Ideal Predicted Chlorine loss rate

  1. Back To Top    #1
    JoyfulNoise's Avatar
    Join Date
    May 2015
    Location
    Tucson, AZ
    Posts
    11,625

    Question (NOT URGENT :) ) Ideal Predicted Chlorine loss rate

    I've look through the Pool Water Chemistry post and I have not found what I'm looking for. Is there a closed form equation (or even an interpolated equation or regression analysis) that describes the chlorine loss rate as function of FC level (and any other relevant water parameters such as pH, CYA, etc) where there is no UV exposure and no known loss due to disinfection or oxidation?

    The reason I ask is this - for an OCLT where you're just checking to see if you have a problem, I have seen any number of different variations of recommended FC levels. Some have recommended that an OCLT really only tells you something if your at shock levels (one of the exit criteria for a SLAM), others say to do an OCLT at whatever FC level your water happens to be at when nightfall comes (this is the actual TFP Pool School method) and I've seen others recommend raising the FC up to 10ppm at sundown and then checking again in the morning.

    So my question/inquiry is just to get a feeling for what the loss would be for a given FC level assuming the ideal state that you have no sunlight and no contamination in the water (organics or biological). Perhaps it's so low that it doesn't matter or would not be detectable by FAS-DPD testing, but I just have not found it yet.

    Thanks.
    Matt
    16k IG PebbleTec pool, 650gal spa, spillway and waterfall, 3HP IntelliFlo VS / 1.5HP WhisperFlo, Pentair QuadDE-100 filter, IC40 SWCG, MasterTemp 400k BTU/hr NG heater, KreepyKrauly suction-side cleaner Dolphin S300i robot, EasyTouch controls, city water, K-1001, K-2006 and K-1766 test kits, Mannitol test for borates

  2. Back To Top    #2

    TFP Guide

    pabeader's Avatar
    Join Date
    May 2015
    Location
    Dallas Ga
    Posts
    4,064

    Re: (NOT URGENT :) ) Ideal Predicted Chlorine loss rate

    You know as well as I, that CG will have that available. But I do know that the thinking around the raised FC is that OCLT is usually done to decide if it's time to stop the SLAM. Since you are at SLAM level a 1ppm Cl loss would be less %wise then if you were at like 4 or 5 ppm Cl.
    Bob - Palm Beach by San Juan Pools. approx 5000 gals., Pentair 320 cartridge filter (all new guts installed by me), Goldline SWG, 'New to me' Kreepy Krauly Sand Shark, Intermec 104 Timer Test kit: TF-100 w/Speed Stir

  3. Back To Top    #3
    JoyfulNoise's Avatar
    Join Date
    May 2015
    Location
    Tucson, AZ
    Posts
    11,625

    Re: (NOT URGENT :) ) Ideal Predicted Chlorine loss rate

    Quote Originally Posted by pabeader View Post
    You know as well as I, that CG will have that available. But I do know that the thinking around the raised FC is that OCLT is usually done to decide if it's time to stop the SLAM. Since you are at SLAM level a 1ppm Cl loss would be less %wise then if you were at like 4 or 5 ppm Cl.
    Are you accusing me of baiting chemgeek actually I admit I'm on my phone a lot and searching for stuff takes 10X longer so I was hoping for an answer but I will continue my search nonetheless.

    Lots of folks use an OCLT outside the SLAM process as a diagnostic. So that's where my thought process lies.


    Matt
    16k IG PebbleTec pool, 650gal spa, spillway and waterfall, 3HP IntelliFlo VS / 1.5HP WhisperFlo, Pentair QuadDE-100 filter, IC40 SWCG, MasterTemp 400k BTU/hr NG heater, KreepyKrauly suction-side cleaner Dolphin S300i robot, EasyTouch controls, city water, K-1001, K-2006 and K-1766 test kits, Mannitol test for borates

  4. Back To Top    #4

    TFP Guide

    pabeader's Avatar
    Join Date
    May 2015
    Location
    Dallas Ga
    Posts
    4,064

    Re: (NOT URGENT :) ) Ideal Predicted Chlorine loss rate

    mine too. I'm just circumspect about it.
    "Since OCLT is intended for SLAM, you need to be at SLAM to use it." Would be a more straight forward way for me to say it.
    Bob - Palm Beach by San Juan Pools. approx 5000 gals., Pentair 320 cartridge filter (all new guts installed by me), Goldline SWG, 'New to me' Kreepy Krauly Sand Shark, Intermec 104 Timer Test kit: TF-100 w/Speed Stir

  5. Back To Top    #5

    In the Industry

    duraleigh's Avatar
    Join Date
    Apr 2007
    Location
    Sebring, Florida
    Posts
    30,085

    Re: (NOT URGENT :) ) Ideal Predicted Chlorine loss rate

    Yes, but.......... This comes up often and the multiple answers JYN is alluding to are very real and somewhat confusing. We need a standard.

    My take is that the FC loss experienced during the OCLT is arithmetic, not a percentage or a function of the available FC in the pool If your organic level in the pool is such that you consume X ppm FC to fight it, that X ppm will be the same regardless of the available FC.

    I do not know if I am right but it seems logical.

    Probably more important than getting it nailed perfectly is that we all get on a number we can live with. I believe it should be whatever is your current FC and that's that. It simplifies the test and saves a lot of time.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

  6. Back To Top    #6

    TFP Guide

    pabeader's Avatar
    Join Date
    May 2015
    Location
    Dallas Ga
    Posts
    4,064

    Re: (NOT URGENT :) ) Ideal Predicted Chlorine loss rate

    Is that true though. I'm thinking it is but just to play the other side for a minute.

    Let's say that at 4ppm Cl I have enough stuff(X) to loose 1ppm Cl in 8 hours.
    If I am at 12ppm Cl will X stuff still cause a loss of 1ppm Cl in 8 hours?
    Bob - Palm Beach by San Juan Pools. approx 5000 gals., Pentair 320 cartridge filter (all new guts installed by me), Goldline SWG, 'New to me' Kreepy Krauly Sand Shark, Intermec 104 Timer Test kit: TF-100 w/Speed Stir

  7. Back To Top    #7
    JoyfulNoise's Avatar
    Join Date
    May 2015
    Location
    Tucson, AZ
    Posts
    11,625

    Re: (NOT URGENT :) ) Ideal Predicted Chlorine loss rate

    My original question did not deal with external losses (organic or biological in nature) BUT just the intrinsic loss rate of active chlorine (hypochlorous acid). Left alone by itself, hypochlorous acid degrades into chloride with no external input (UV or "stuff").



    Matt
    16k IG PebbleTec pool, 650gal spa, spillway and waterfall, 3HP IntelliFlo VS / 1.5HP WhisperFlo, Pentair QuadDE-100 filter, IC40 SWCG, MasterTemp 400k BTU/hr NG heater, KreepyKrauly suction-side cleaner Dolphin S300i robot, EasyTouch controls, city water, K-1001, K-2006 and K-1766 test kits, Mannitol test for borates

  8. Back To Top    #8

    TFP Guide

    pabeader's Avatar
    Join Date
    May 2015
    Location
    Dallas Ga
    Posts
    4,064

    Re: (NOT URGENT :) ) Ideal Predicted Chlorine loss rate

    Sometimes a 'simple' question, turns out to lead into a more interesting place...
    Bob - Palm Beach by San Juan Pools. approx 5000 gals., Pentair 320 cartridge filter (all new guts installed by me), Goldline SWG, 'New to me' Kreepy Krauly Sand Shark, Intermec 104 Timer Test kit: TF-100 w/Speed Stir

  9. Back To Top    #9
    JoyfulNoise's Avatar
    Join Date
    May 2015
    Location
    Tucson, AZ
    Posts
    11,625

    Re: (NOT URGENT :) ) Ideal Predicted Chlorine loss rate

    Quote Originally Posted by duraleigh View Post
    Yes, but.......... This comes up often and the multiple answers JYN is alluding to are very real and somewhat confusing. We need a standard.

    Probably more important than getting it nailed perfectly is that we all get on a number we can live with. I believe it should be whatever is your current FC and that's that. It simplifies the test and saves a lot of time.
    Just to demonstrate what a doofus I am, I was totally thinking to myself, "What the heck does JYN mean??" indeed!!

    I agree, make it as easy as possible. For me, bumping up to 10ppm is no sweat, it's not even 2 gallons of bleach. For other larger pool owners, going to 10ppm could be a real pain. So no need to be wasteful.


    Matt
    16k IG PebbleTec pool, 650gal spa, spillway and waterfall, 3HP IntelliFlo VS / 1.5HP WhisperFlo, Pentair QuadDE-100 filter, IC40 SWCG, MasterTemp 400k BTU/hr NG heater, KreepyKrauly suction-side cleaner Dolphin S300i robot, EasyTouch controls, city water, K-1001, K-2006 and K-1766 test kits, Mannitol test for borates

  10. Back To Top    #10
    JoyfulNoise's Avatar
    Join Date
    May 2015
    Location
    Tucson, AZ
    Posts
    11,625

    Re: (NOT URGENT :) ) Ideal Predicted Chlorine loss rate

    Quote Originally Posted by pabeader View Post
    Sometimes a 'simple' question, turns out to lead into a more interesting place...
    Ah yes, chasing the rabbit down the rabbit hole can lead to some "interesting" places....I believe a little girl named Alice found that out....


    Matt
    16k IG PebbleTec pool, 650gal spa, spillway and waterfall, 3HP IntelliFlo VS / 1.5HP WhisperFlo, Pentair QuadDE-100 filter, IC40 SWCG, MasterTemp 400k BTU/hr NG heater, KreepyKrauly suction-side cleaner Dolphin S300i robot, EasyTouch controls, city water, K-1001, K-2006 and K-1766 test kits, Mannitol test for borates

  11. Back To Top    #11

    In the Industry

    duraleigh's Avatar
    Join Date
    Apr 2007
    Location
    Sebring, Florida
    Posts
    30,085

    Re: (NOT URGENT :) ) Ideal Predicted Chlorine loss rate

    My original question did not deal with external losses (organic or biological in nature) BUT just the intrinsic loss rate of active chlorine (hypochlorous acid).
    Yeah, I hi-jacked just a bit but I do not think there is enough "decay" that we can measure it as pool guys. (Fas-DPD .5 ppm resolution).

    While that "decay" would certainly be a % drop, I don't think it would be large enough to overcome the leeway we have built in @ 1 ppm loss. Does that make sense? Certainly, we get many reports of 0 FC loss while conducting an OCLT so that would seem to indicate that "decay" would be pretty darn small/
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

  12. Back To Top    #12

    In the Industry

    duraleigh's Avatar
    Join Date
    Apr 2007
    Location
    Sebring, Florida
    Posts
    30,085

    Re: (NOT URGENT :) ) Ideal Predicted Chlorine loss rate

    Quote Originally Posted by pabeader View Post
    Is that true though. I'm thinking it is but just to play the other side for a minute.

    Let's say that at 4ppm Cl I have enough stuff(X) to loose 1ppm Cl in 8 hours.
    If I am at 12ppm Cl will X stuff still cause a loss of 1ppm Cl in 8 hours?
    It sure seems to me like it would. If we think a bit backwards as if the FC is being consumed by the x ppm organics, then we could logically say that the amount or organics in the pool ONLY consumes 1 ppm overnight because x ppm organics is a fixed value.

    Another way of looking at it..."If I am at 12ppm Cl will X stuff still cause a loss of 1ppm Cl in 8 hours?" would be, "Why not? There is no increased demand."
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

  13. Back To Top    #13

    Join Date
    Mar 2007
    Location
    San Rafael, CA USA
    Posts
    12,082

    Re: (NOT URGENT :) ) Ideal Predicted Chlorine loss rate

    First of all, you can completely ignore the type of degradation you see with chlorinating liquid and bleach since that is ONLY for very concentrated solutions and varies as the square of the concentration. Even at yellow/mustard SLAM levels, the concentration of chlorine is over 50,000 times smaller than bleach and the rate of breakdown is over a billion times slower.

    Losses in terms of rates are ALWAYS proportional to the concentrations of the reacting chemical species. The only time you look at absolute quantities rather than concentrations is when the reactions are so fast that the net loss is limited by the chemical being added such as adding hydrogen peroxide to dechlorinate. SLAM levels have higher chlorine bound to CYA and chlorine unbound to CYA levels so will have chlorine react faster and therefore drop faster from such reactions.

    The loss of chlorine when there is no sunlight comes from the following sources:

    • Chlorine oxidation of CYA.
    • Chlorine oxidation of pool covers
    • Chlorine oxidation of ammonia/chloramines and organics or other chemicals in the water (e.g. HEDP, Polyquat)
    • Chlorine oxidation of metal and other materials

    For chlorine oxidation of CYA, see Degradation of Cyanuric Acid (CYA) where it may be hypochlorite ion that participates in such oxidation and that it would therefore occur faster at higher pH (see the fourth graph in this post). Note that because CYA is a hypochlorous acid buffer, when the pH is higher the HOCl is largely prevented from dropping but that means that hypochlorite ion (OCl-) rises a lot more. At normal FC/CYA levels, the CYA loss may be around 2-3 ppm per month from CYA losses I've seen in my pool over many months and repeated testing over many years which implies a chlorine loss of 5-7.5 ppm per month or 0.17 to 0.25 ppm FC per day. If one were at SLAM levels with the pH at 7.5, then this is around 10 times higher so 1.7 to 2.5 ppm FC per day. In practice, we don't see the losses be this high (which may be because my FC/CYA ratios varies from 7.5% to 15%), but if one does a SLAM at higher pH because one didn't lower the pH a lot before the SLAM than the chlorine oxidation of CYA may push one over the 1 ppm OCLT limit (remember OCLT is done overnight so normally 8-12 hours so at regular SLAM the chlorine oxidation of CYA may be 1.7*(8/24) = 0.6 to 2.5*(12/24) = 1.25). Wojtowicz in his paper claims much higher CYA losses and associated chlorine demand.

    Nevertheless, there are reports of CYA loss during extended SLAM, but that also includes losses during the day that may occur from sunlight breakdown creating more hydroxyl radicals that may oxidize CYA more quickly.

    In my pool, I have a pool cover and it contributes to most of my losses which with no sunlight are 0.7 ppm FC per day at regular FC/CYA levels so I figure that perhaps 0.2 of that is from oxidation of CYA and 0.5 is from oxidation of the cover. This is at 88F water temperature and the chlorine loss rate will be temperature dependent which is why chlorine usage drops so dramatically in colder water. Again, these are 24-hour losses while the OCLT is 1/3rd to 1/2 that since it's generally over 8-12 hours.

    Also don't forget that there is a +/- 10% error on readings and while we are looking at relative readings, not absolute, I doubt people can do much better than +/- 5%. 1 ppm FC loss with such an error would be seen at an FC of only 20 ppm. So a high FC SLAM could make an OCLT difficult. This is why I think doing an OCLT at something more like 10 ppm FC is better, but we started out recommending it for a SLAM as a criteria for when to stop a SLAM. We've seen this criteria be difficult for some people to achieve, especially when they have high FC levels due to higher CYA levels. Also, one would expect to have higher CYA losses and therefore higher chlorine demand at higher CYA levels even if the hypochlorite ion concentration were constant.

    The basic idea of the OCLT is sound in that it certainly detects higher than normal chlorine demand, but for "normal" chlorine losses it can be difficult to pass that test let alone measure it accurately.

    The bottom line is that we don't have good data for the chlorine loss rate oxidizing CYA and the Wojtowicz numbers are much higher than normally seen.

    Look at this thread from this post on for the level of craziness demanding precise meeting of all three criteria in spite of the high FC for this half-SLAM. Do we really believe that people measuring a 10 ml water sample are doing better than +/- 5% in such measurement which would be +/- 0.5 ml? Seriously? A 5% error at 34 ppm FC would be 1.7 ppm FC which exceeds the 1 ppm OCLT limit. I'll bet that the next day this person might have the CC at 0.5 or below instead of the current 1.0, but that they won't hit 34 ppm and might be at 32 or 36 at which point people will say "you're failing the OCLT".

    This is the problem with over-simplifying everything. While it's nice to have simple criteria, they can't realistically be applied across broad ranges. The actual effects are proportional so real criteria would be proportional, but of course that's more complicated not only for the extra multiplying math involved but the measurement errors that have both proportional (percentage) error AND absolute (+/- 1 drop) error.
    16,000 gallon outdoor in-ground 16'x32' plaster pool; Pentair Intelliflo VF pump; Pentair IntelliTouch i9+3s control system; Jandy CL-340 square foot cartridge filter
    12 Fafco solar panels; Purex Triton PowerMax 250 natural gas heater (200,000 BTU/hr output); automatic electric pool safety cover; 4-wheel pressure-side "The Pool Cleaner"

  14. Back To Top    #14
    JoyfulNoise's Avatar
    Join Date
    May 2015
    Location
    Tucson, AZ
    Posts
    11,625

    Re: (NOT URGENT :) ) Ideal Predicted Chlorine loss rate

    All,

    Thank you for the posts and replies. It has been a thoroughly enlightening conversation. In the future, if I see posts that use an OCLT, I'll be much less confused (relative to my normal baseline confusion ).

    Quote Originally Posted by chem geek View Post
    The basic idea of the OCLT is sound in that it certainly detects higher than normal chlorine demand, but for "normal" chlorine losses it can be difficult to pass that test let alone measure it accurately.

    The bottom line is that we don't have good data for the chlorine loss rate oxidizing CYA and the Wojtowicz numbers are much higher than normally seen.
    chemgeek,

    Thank you for the post and the links as well as that detailed list of the degradation sources. In my pool, the largest contributor(s) to FC loss would likely be the higher CYA levels and any organic oxidation as I do not have any metals in my pool nor do I use a solar cover.

    One question pops into mind - is lowering the pH initially to 7.0 before adding any additional FC for an OCLT advisable as a way of minimizing the amount of CYA oxidation since the proportion of free hypochlorite ions to hypochlorous acid is lower? Perhaps it's too small to make a difference and therefore, like trying to raise the FC to shock levels, just a waste of muriatic acid.
    Matt
    16k IG PebbleTec pool, 650gal spa, spillway and waterfall, 3HP IntelliFlo VS / 1.5HP WhisperFlo, Pentair QuadDE-100 filter, IC40 SWCG, MasterTemp 400k BTU/hr NG heater, KreepyKrauly suction-side cleaner Dolphin S300i robot, EasyTouch controls, city water, K-1001, K-2006 and K-1766 test kits, Mannitol test for borates

  15. Back To Top    #15

    Join Date
    Mar 2007
    Location
    San Rafael, CA USA
    Posts
    12,082

    Re: (NOT URGENT :) ) Ideal Predicted Chlorine loss rate

    We recommend lowering the pH before a SLAM because adding a hypochlorite source of chlorine to water that has CYA in it will have the pH rise a lot due to CYA's trying to buffer hypochlorous acid. The result is that adding chlorine results in about twice the pH rise compared to not having any CYA in the water. We recommend this pH lowering before a SLAM not so much to lessen oxidation of CYA, but rather to prevent metal staining from high pH and to have the chlorine still be reasonably be effective because while CYA does buffer chlorine it's not perfect and a large pH rise will still affect it.
    16,000 gallon outdoor in-ground 16'x32' plaster pool; Pentair Intelliflo VF pump; Pentair IntelliTouch i9+3s control system; Jandy CL-340 square foot cartridge filter
    12 Fafco solar panels; Purex Triton PowerMax 250 natural gas heater (200,000 BTU/hr output); automatic electric pool safety cover; 4-wheel pressure-side "The Pool Cleaner"

  16. Back To Top    #16

    In the Industry

    duraleigh's Avatar
    Join Date
    Apr 2007
    Location
    Sebring, Florida
    Posts
    30,085

    Re: (NOT URGENT :) ) Ideal Predicted Chlorine loss rate

    So, I still don't know if the OCLT can be performed at 4 ppm? 10 ppm? SLAM value? All of the above seems to be the answer, I think.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

  17. Back To Top    #17

    Join Date
    Jan 2014
    Location
    Buckeye AZ
    Posts
    807

    Re: (NOT URGENT :) ) Ideal Predicted Chlorine loss rate

    I would think, whichever level minimizes the effect of sample/testing variance. Passing an OCLT at a FC in the 30's is very hard because over that many drops you are just increasing the chance of accumulating testing error in one direction or the other. At a maintenance level of 5 or 7 PPM, you might not get a good idea of just how fast your chlorine is getting chewed up. Might only lose .8 at a FC of 5 (PASS!), but might have lost 1.0 at a FC of 10 (FAIL!). right?

    So in my unscientific analysis the idea of elevate, but not high, would make sense.

    Of course, if you are slamming at 20 or 25...do you dare let your FC drop down to 10 just to do the test? You might lose a few days worth of fighting algae during that window.

    edit: this would not make it simpler, but perhaps instead of a fixed 1 PPM FC drop, it should be a % of the CYA/FC ratio, to adjust for your SLAM level. Or some formula where you take the target, divided by the SLAM level, then extrapolate.
    10,500 gal IG, Topaz Pebble, auto-level
    Hayward DE filter, 2HP Ecostar VSP, ProLogic PS-4, GVA actuators
    Cal Pools Wave Force Plus (wall return jets plus 2 floor pop-ups), Venturi Skimmer
    Water sheer, 2 wok pots, bubbler stem on the baja step
    ColorLogic Mutlicolor LED lamp. Taylor 2006+speed stir

  18. Back To Top    #18
    Mod Squad pooldv's Avatar
    Join Date
    Aug 2012
    Location
    DFW, TX
    Posts
    23,999

    Re: (NOT URGENT :) ) Ideal Predicted Chlorine loss rate

    Seems to me that 10 or less is the better answer.

    Or

    We change it from a loss of 1 ppm is a fail to a loss of 1 ppm under 10 ppm or a loss of x% over 10 ppm.
    TFP Moderator
    If TFP helped you or saved you money - Become a TFP Supporter! <--Click here
    2012 build and pics, 20k gal gunite, black onyx pebblesheen, OK flagstone, IntellifoVS, cart filter w/Pleatco, IC40 SWG, Solartouch, 5 12'x4' solar panels, HP50HA heat pump, 8mil solar cover, borates, TF-100 test kit, SONOS, Doheny's Discovery Robot, hot tub on bleach

  19. Back To Top    #19

    Join Date
    Mar 2007
    Location
    San Rafael, CA USA
    Posts
    12,082

    Re: (NOT URGENT :) ) Ideal Predicted Chlorine loss rate

    This has been discussed in several threads before including OCLT Instructions, OCLT, and OCLT preference. The issue there was that if one does an OCLT at normal FC/CYA levels then 1 ppm FC is too loose a criteria and one would normally expect a smaller loss. On the other hand for a yellow/mustard algae SLAM level one would expect a higher OCLT than at a regular SLAM level.

    The main problem even with a regular SLAM OCLT is in testing accuracy. Most people wouldn't be able to measure their water sample 10 ml volume with better than +/- 5% (0.5 ml) accuracy. So the OCLT amount could easily vary by +/- 5%. 5% of 20 ppm is 1 ppm so it doesn't take a particularly high FC level to get greater than a 1 ppm FC loss simply from the inaccuracy of testing unless one is extraordinarily careful.

    So if not doing a SLAM, the advice would be to raise the FC to 10 ppm so that the chlorine loss rate is more obvious overnight and that the 1 ppm FC criteria is reasonable. If doing a regular SLAM, then if the OCLT is within test error (say, +/- 5%) then it passes. At 20 ppm FC (a SLAM for 50 ppm CYA), a 5% higher on the high side at night and a 5% lower on the low side in the morning would be 2 ppm FC. One can either try and be more careful in testing or can redo the test another night since statistically one doesn't bounce back and forth between errors in a consistent pattern (one may have a bias, but an OCLT will cancel that out). At higher than 20 ppm FC the 1 ppm OCLT criteria is too strict -- OCLT is still useful to see trends if the demand was large and then declines, but 1 ppm is too tight a criteria for ending a high FC SLAM.

    Remember that the purpose of the OCLT was to make sure that people hold a SLAM until they've largely broken through excessive chlorine demand. So long as there isn't visible algae then lowering the FC level to normal is still going to keep oxidizing anything that has a chlorine demand -- it will just do so more slowly. The biggest risk of ending a SLAM early is from not killing off clumped algae.
    16,000 gallon outdoor in-ground 16'x32' plaster pool; Pentair Intelliflo VF pump; Pentair IntelliTouch i9+3s control system; Jandy CL-340 square foot cartridge filter
    12 Fafco solar panels; Purex Triton PowerMax 250 natural gas heater (200,000 BTU/hr output); automatic electric pool safety cover; 4-wheel pressure-side "The Pool Cleaner"

  20. Back To Top    #20

    In the Industry

    duraleigh's Avatar
    Join Date
    Apr 2007
    Location
    Sebring, Florida
    Posts
    30,085

    Re: (NOT URGENT :) ) Ideal Predicted Chlorine loss rate

    So if not doing a SLAM, the advice would be to raise the FC to 10 ppm so that the chlorine loss rate is more obvious overnight and that the 1 ppm FC criteria is reasonable.
    Well, I think the issue still persists. Why does the FC loss rate become more obvious at 10 ppm than it would have at, say, 5 ppm? Does that mean that the Overnight Chlorine Loss is a % of the FC?

    The sample accuracy can be improved by going to a 25 ml sample,
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

Page 1 of 2 12 LastLast

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •