Become a TFP Supporter Pool Math Forum Rules Pool School
Results 1 to 7 of 7

Thread: High FC and CYA - help with dilution to get numbers

  1. Back To Top    #1

    Join Date
    Sep 2016
    Location
    Houston, TX
    Posts
    30

    High FC and CYA - help with dilution to get numbers

    Hello TFP community, new to the group but have been surfing the forum for the past few weeks. I bought a home 2 yrs ago which already had a pool/spa and it is covered by screened in pool cage, so it remains virtually debris free. Never was a pool owner or had any knowledge of such until I acquired this pool. Over the past year, I researched and became familiar with my equipment, but stayed away of the chemistry and hired that part out (and have been through several bad experiences). I've stayed away from Leslies for the most part and buy parts and what not online and have had success. My pool education has all been online which is how I came across this awesome forum, and I've always been impressed as many times my google results often lead me here where I've followed trails of sound advice.

    Wanting to get a better understanding of the chemistry, about a month ago I bought a Taylor K2006 - I also wanted to keep my pool tech honest. I read the pool school details and absorbed as much as I could in the area. I've had my current pool tech for about a year and they pretty much have done not much weekly except fill up my two puck floaters (they insisted on two, one in pool and one in spa) with about 4 pucks each week. Every now and then they would add acid or some shock, but they didn't leave much on those details on the weekly report. I really didn't pay much attn to all of that because my pool has been blue and that is what I was paying for, right?

    So, in my search to keep my pool person honest, I pulled the weekly reports for the last 2 months. After reviewing, I noticed the CYA crept up from 60 to 100 (assuming the tech was accurate on their readings). My understanding is high CYA is due to the puck usage, and after reading this forum, it seems most here are fans of liquid chlorine once your CYA is balanced around 40. So last week I took my first reading:

    My Results:
    FC - pink never turned clear - thought I was doing something wrong
    CC - without FC, could not get this
    ph-7.4
    TA - turned yellow
    CH - 260
    CYA - over 100

    Pool Tech Last Results
    CL - 5 - They call it chlorine on their report, but I assume it is FC.
    ph 7.4
    TA 100
    CYA 100
    CH 230

    Since I couldn't get FC, I ran the test again. Thought I had bad reagent or wasn't doing the test right. Went to Leslies to have them test because I thought I was doing something wrong, and that is when I learned about bleaching out, and how high FC can skew all of your results. Advice of Leslies was to drain to get CYA down and then start rebalancing. His other recommendation was to pull the puck dispensers, wait for FC to come down and then start treating with liquid chlorine and after a while, the CYA will eventually come down. He also recommended to test every other day to keep an eye on the FC levels.

    So I came home and pulled pulled the floaters out and wanted to figure out how to get accurate FC and CYA measurements. Came to TFPC and understood that I can use the dilution method, so I did, but just for CYA and FC.

    CYA - for this test, I diluted using equal parts tap water and pool water (didn't have distilled) and found my CYA to be 144.
    FC - used distilled water (finally got some), and the equal parts still never would have the water go clear up to 30 drops of 0871; so I diluted with 2 parts of distilled and 1 part of pool water and I finally had success. It took 19 drops at the 10ml line, which if I did my math properly is 19 * .5 * 3 =28.5. So I assume I have FC of 28.5 or around there..is that right?

    So I guess after all of this, I'm looking for some advice on what ya'll would do here. Pool tech is slated to come out here on Tue, and I plan firing them on the spot b/c I cannot believe it could raise (assuming their numbers were reasonably accurate) from 60 to 144 in 2 months, and they haven't even bothered to tell me anything about it. It was only because I tested that I found this out.

    Thanks for the help and advice.
    15K gal rectangle with 1K gal spill over round spa | K-2006 Test kit | IG plaster | B2983 1.5HP 2 speed pump| Triton TR100 sand filter | Pentair MiniMax 400k BTU heater | Stenner 45MPHP10 w/ 15g tank | Dolphin M400 robot | screened pool cage covers pool entirely to keep it debris free and adds SPF | sun exposure estimate 8hr daily.

  2. Back To Top    #2
    Mod Squad pooldv's Avatar
    Join Date
    Aug 2012
    Location
    DFW, TX
    Posts
    23,994

    Re: High FC and CYA - help with dilution to get numbers

    Welcome to TFP!

    We are all in favor of maintaining your own pool. The FAS/DPD chlorine test can test FC up to 50 ppm. So, it is odd that you had any trouble with it.

    Yes, trichlor pucks and bags of dichlor shock will quickly raise your cya. They add almost as much CYA as they add chlorine.
    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

  3. Back To Top    #3


    TFP Guide

    domct203's Avatar
    Join Date
    Jun 2015
    Location
    CT
    Posts
    3,374

    Re: High FC and CYA - help with dilution to get numbers

    As mentioned, the FAS/DPD chlorine test will test up to 50ppm, no need to dilute, doing so is just adding error to the test.

    For the FC test, you said the pink never turned clear.... Are you saying that after adding a heaping scoop of R-870 powder to your sample the water turned pink, but you stopped adding drops of R-871 before the water went clear?

    If so, you need to keep adding drops of R-871 until the sample changes to clear. It will change, but at 28ppm it will take 56 drops with a 10ml sample.

    How are you getting 144ppm for the CYA result? The CYA scale is in 10ppm increments. If you get a reading between numbers it is best to round up to the next 10ppm.

    I'm not sure what's up with your TA test, can you describe your steps leading up to the yellow result?
    Dom - TFP Guide
    Intex 18' X 48" Ultra Frame AGP 6700 gallons | Two Intex CS8110 SWG's | Hayward Pro Series 21" Sandfilter | Hayward 1.5HP Power Flo Matrix pump | Hayward Thru-wall Skimmer | Wanda the Whale | 72 sq ft of Sungrabber Solar Panels with Hayward GLC-2P-A | Taylor K2006 Test Kit, Sample Sizer & Speed Stir | Click Here To Become a TFP Supporter!

  4. Back To Top    #4
    Mod Squad pooldv's Avatar
    Join Date
    Aug 2012
    Location
    DFW, TX
    Posts
    23,994

    Re: High FC and CYA - help with dilution to get numbers

    More here on yellow TA tests, Pool School - Extended Test Kit Directions
    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

  5. Back To Top    #5

    Join Date
    Sep 2016
    Location
    Houston, TX
    Posts
    30

    Re: High FC and CYA - help with dilution to get numbers

    Being that it was my first test, I had expected it at least in the ball park of what my tech had reported so I ran the test the first time and when I had gotten up to 30 drops at 25ml, I figured I did something wrong. So I started over and went to 50, still pink and again thought I did something wrong.

    Today i I repeated the test, this time diluting (1 part pool/1 part distilled) and and used 25ml again added 30 drops and it was stil pink. Dumped it all and created a new solution ( 1 pool, 2 distilled) and used 10ml ( figuring 10 uses less drops). 19 drops later it was clear.

    Yes i used 2 heaps of the powder.

    For cya, I diluted using 1 part pool, 1 tap and the black dot disappeared between just over 70, so I guessed 72 and doubled.

    For TA, I followed the steps as described on Taylor kit but instead of changing to red it turned yellowish.

    As as a first time tester, I was beginning to doubt I had the right test kit ��

    Sounds like I need to run a non diluted at 10ml and just hang in there, right? I'll go up to 100 drops, hope I have enough drops. Which begs the question, where do y'all source refills?
    15K gal rectangle with 1K gal spill over round spa | K-2006 Test kit | IG plaster | B2983 1.5HP 2 speed pump| Triton TR100 sand filter | Pentair MiniMax 400k BTU heater | Stenner 45MPHP10 w/ 15g tank | Dolphin M400 robot | screened pool cage covers pool entirely to keep it debris free and adds SPF | sun exposure estimate 8hr daily.

  6. Back To Top    #6

    Join Date
    Aug 2014
    Location
    Northern IL
    Posts
    4,615

    Re: High FC and CYA - help with dilution to get numbers

    I get my refills on amazon through Amato industries. TFtestkits sells them also.

  7. Back To Top    #7

    Join Date
    Sep 2016
    Location
    Houston, TX
    Posts
    30

    Re: High FC and CYA - help with dilution to get numbers

    Thx for the refill detail.

    I just retested and here are my numbers:
    FC 27.5 (looks like the dilution method is accurate)
    CC .5
    pH 7.8
    TA 150
    CH 275
    CYA 140

    so I guess I got my dilution questions answered. I'll open a new thread for advice on my numbers. Thx all.
    15K gal rectangle with 1K gal spill over round spa | K-2006 Test kit | IG plaster | B2983 1.5HP 2 speed pump| Triton TR100 sand filter | Pentair MiniMax 400k BTU heater | Stenner 45MPHP10 w/ 15g tank | Dolphin M400 robot | screened pool cage covers pool entirely to keep it debris free and adds SPF | sun exposure estimate 8hr daily.

Posting Permissions

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