+ Reply to Thread
Results 1 to 9 of 9

Thread: New to BBB and have a question about Best Guess Chart

  1. #1
    Join Date
    Jun 2011
    Posts
    11

    Default New to BBB and have a question about Best Guess Chart

    I understand the chart in terms of for the given range of stabilizer I should maitain my FC at the respective levels; however, I do not understand what the 'shock' or +shock+ numbers mean or what the " ' " and "+" means? If my pool is not at the prescribed levels how do I calculate how much bleach to add to my pool to raise the FC levels?

  2. #2
    PoolDoc's Avatar
    PoolDoc is offline Administrator Quark Inspector PoolDoc 5 stars PoolDoc 5 stars PoolDoc 5 stars PoolDoc 5 stars PoolDoc 5 stars PoolDoc 5 stars PoolDoc 5 stars
    Join Date
    Jan 2005
    Location
    Georgia
    Posts
    11,386

    Default Re: New to BBB and have a question about Best Guess Chart

    Hi Army . . .

    + The 'shock' level is what you need, say after a party or at first hint of algae. The +shock+ level is what you may need is the algae kept 'hinting' AFTER you boosted to the shock level, or when there's a problem that won't go away.

    + Calculating doses is based on ppm -- parts per million, or more to the point, pounds of stuff per million pounds of pool water.

    Example: A typical 75' smallish community pool has 120,000 gallons, or about 1,000,000 lbs of water (8.3#/gallon). Stabilizer is 100% active, so if I add a pound of stabilizer to that pool, I get a 1 ppm (ie, 1# per millon #'s) increase in CYA. On the other hand, since diclor is either 55% or 62% active, I get about 0.6 #'s of stuff per pound of dichlor. So . . . to add a 3 ppm dose of CHLORINE to that same pool I need 3/0.6 #'s or 5#'s of dichlor.

    Example 2: Say I have an Intex pool with 5,000 gallons. 5,000 gallons is 41,500 #'s or 4.2% of the million pound community pool. So it has a "pool factor" of 1/0.0415 or 24. The "Pool Factor"is what you multiple your stuff with, to find your dose. On this Intex pool, each # of stabilizer will add 24 ppm of CYA.

    Method:
    #1 - find your Pool Factor, and write it down. (PF = 120,000 / [your pool gallons]). The PF for a 10,000 gallon pool is 12.
    #2 - find the active % of the chemical you add. 6% household bleach is, well, 6% active.

    If you want ppm per unit dose (say, ppm per gallons of bleach) do this:
    #3 - PF x Active% x dose pounds, like this for our 10K gallon pool: 12 x 0.06 x 8.5 (lbs per gallon of bleach) = 6.12. So, a gallon of plain household bleach adds about 6ppm of chlorine to a 10K gallon pool.

    If you want to add a particular ppm to a particular pool, do this:
    #3 - PPMd (PPM desired) is say, 15 ppm 'shock' dose, and say you've got dichlor. Here's the calc; (PPMd / PF) / Active% = dose pounds, like this: (15 / 12) / 0.6 = 1.25/0.6 or 2.01.
    SO . . . you need 2# of dichlor to shock a 10K pool

    Ben

  3. #3
    CarlD's Avatar
    CarlD is offline SuperMod Emeritus Vortex Adjuster CarlD 4 stars CarlD 4 stars CarlD 4 stars CarlD 4 stars CarlD 4 stars CarlD 4 stars
    Join Date
    Dec 1969
    Location
    North Central NJ
    Posts
    6,607

    Default Re: New to BBB and have a question about Best Guess Chart

    I use a simpler but related method, that's only good for add bleach/liquid chlorine, that I call The Rule of Thumb:

    1 gallon of 6% bleach adds 6ppm of FC to 10,000 gallons of water.
    1 gallon of 5.25% bleach adds 5.25ppm of FC to 10,000 gallons of water.
    1 gallon of 12.5% liquid chlorine adds 12.5 ppm to 10,000 gallons of water.

    If you have 20,000 gallons, then you need 2 gallons to get the same effect. If you only use 1 gallon you'll get half as much FC.
    If you have 5,000 gallons you need half as much (2 quarts) to get the same effect. If you use 1 gallon you'll get double the FC.

    So, if you have 30,000 gallons, you need 3 gallons to get the effect of 1 gallon in 10,000 gallons.
    If you have 15,000 gallons, you need 1.5 gallons (or 6 quarts) to get the effect of 1 gallon in 10,000 gallons.

    If your pool in 13,000 gallons, you can use the 15,000 gallon approximation, etc.

    NOTE: This does not work for dry chlorine forms like dichlor, tri-chlor and cal-hypo.

    Carl
    Carl

  4. #4
    Join Date
    Jun 2011
    Posts
    11

    Default Re: New to BBB and have a question about Best Guess Chart

    Thanks for the info and the equations. So if my CYA is 30ppm and I'm going to shock my pool. The chart says shock 15. Does this mean that I want to raise my cl levels to 15 ppm or a 15 ppm dose?

    Dale

  5. #5
    Watermom's Avatar
    Watermom is offline SuperMod Emeritus Quark Inspector Watermom 4 stars Watermom 4 stars Watermom 4 stars Watermom 4 stars Watermom 4 stars Watermom 4 stars
    Join Date
    Dec 1969
    Location
    Charleston, WV
    Posts
    9,345

  6. #6
    CarlD's Avatar
    CarlD is offline SuperMod Emeritus Vortex Adjuster CarlD 4 stars CarlD 4 stars CarlD 4 stars CarlD 4 stars CarlD 4 stars CarlD 4 stars
    Join Date
    Dec 1969
    Location
    North Central NJ
    Posts
    6,607

    Default Re: New to BBB and have a question about Best Guess Chart

    So, if your FC is 0, or even .5, you'll add chlorine to raise it to 15, which will be adding 15

    But if your FC is 6, you only want to add 9ppm of chlorine to raise it to 15.

    Carl
    Carl

  7. #7
    Watermom's Avatar
    Watermom is offline SuperMod Emeritus Quark Inspector Watermom 4 stars Watermom 4 stars Watermom 4 stars Watermom 4 stars Watermom 4 stars Watermom 4 stars
    Join Date
    Dec 1969
    Location
    Charleston, WV
    Posts
    9,345

    Default Re: New to BBB and have a question about Best Guess Chart

    Quote Originally Posted by CarlD View Post
    So, if your FC is 0, or even .5, you'll add chlorine to raise it to 15, which will be adding 15

    But if your FC is 6, you only want to add 9ppm of chlorine to raise it to 15.

    Carl
    Uhhh ---- isn't that what I said above??

  8. #8
    CarlD's Avatar
    CarlD is offline SuperMod Emeritus Vortex Adjuster CarlD 4 stars CarlD 4 stars CarlD 4 stars CarlD 4 stars CarlD 4 stars CarlD 4 stars
    Join Date
    Dec 1969
    Location
    North Central NJ
    Posts
    6,607

    Default Re: New to BBB and have a question about Best Guess Chart

    I just wanted it to be clear for ArmyTiger that it depended on the starting point.

    I was just a little less terse/cryptic!

    Carl
    Carl

  9. #9
    Join Date
    Jun 2011
    Posts
    11

    Default Re: New to BBB and have a question about Best Guess Chart

    Watermom . . . I understood

    Thanks to both of you for your explanations.

+ Reply to Thread

Similar Threads

  1. Help with best guess chart
    By tim665214 in forum Using Chlorine and Chlorinating Chemicals
    Replies: 7
    Last Post: 08-09-2012, 09:10 AM
  2. Best Guess Chlorine Chart
    By PoolDoc in forum Using Chlorine and Chlorinating Chemicals
    Replies: 0
    Last Post: 03-26-2011, 12:50 PM
  3. Best guess CYA chart question
    By fishandfly in forum Using Chlorine and Chlorinating Chemicals
    Replies: 1
    Last Post: 05-19-2008, 09:24 PM
  4. Best Guess Chart
    By cav in forum Testing and Adjusting Pool Water Chemistry
    Replies: 5
    Last Post: 07-18-2006, 05:13 PM
  5. Best Guess CYA chart
    By Watermom in forum Using Chlorine and Chlorinating Chemicals
    Replies: 0
    Last Post: 04-08-2006, 11:25 AM

Bookmarks

Posting Permissions

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