Become a TFP Supporter Pool Math Forum Rules Pool School
Results 1 to 11 of 11

Thread: Acid turns yellow when added

  1. Back To Top    #1

    Join Date
    Mar 2007
    Location
    Coastalish 'down easter'
    Posts
    4,160

    Acid turns yellow when added

    Hey all

    One of the pools I now work on is an indoor bromine double treadmill pool (plaster, ~ 10 X 45', 3.5 -> 4.5', 'reverse sport pool', bromine (tablet feeder), 7000 gal. ~ 5 months old)

    As said, this pool has 2 high flow 'aqua treadmill' jets, one at either end.

    The pH is always on the high side. SI (from Taylor watergram - sorry, no full #s) is .25 @ pH = 7.4 [my bad, I adjusted the pH down to 7.4, from ~8.0] before running the full tests, ~ 6 hours later

    From memory: the TA was 70 and the CH was 230. Temp is maintained @ 81*

    Whenever I add acid to this pool to lower the constantly 7.8+ pH - it looks like I added pee to the pool - i.e. a yellow cloud where the acid was poured.

    This is a new one for me; is it the bromine, the high pH, or metal (which I doubt)?

    This pool will only be running for another week before it's closed and I'd like to address any issue before it gets ignored for 6 months

    Thank you my TFP friends, for any insight you may be able to shed
    Luv& Luk
    -Ted

    Having done construction and service for 4 pool companies in 4 states starting in 1988, what I know about pools could fill a couple of books - what I don't know could fill a couple of libraries :-D

    POOL SCHOOL, TF Testkits, Jason's Pool Calculator, CYA vs. cl chart, (Just a few DARNED handy links!)

  2. Back To Top    #2

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

    Re: Acid turns yellow when added

    When chlorine is added to a bromine pool (a pool with bromide in it) it can produce so much hypobromous acid locally that some have said it looks yellow (or perhaps it initially produces bromine liquid that looks yellow until it combines with water to produce hypobromous acid). I haven't heard this happening when adding acid, but it's possible that the acid creates more dissolved bromine liquid (Br2) from hypobromous acid (HOBr) though that would be red-brown when concentrated, but perhaps looks yellowish when very dilute. Does the color dissipate after mixing?
    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"

  3. Back To Top    #3

    In the Industry

    Join Date
    Jul 2009
    Location
    London and France
    Posts
    574

    Re: Acid turns yellow when added

    As it's an indoor pool, could it be an effect of the lighting until the acid is fully dispersed? As well as the hyperbromous acid Richard posted.

  4. Back To Top    #4
    Mod Squad Bama Rambler's Avatar
    Join Date
    Jun 2009
    Location
    SouthWest Alabama
    Posts
    22,347

    Re: Acid turns yellow when added

    Change brands of acid and see if that makes a difference.

    Most HCL is made with DI water that has an added step of R/O filtering right at the makeup point to make sure pipe contamination is taken out of the equation, but some mfg's don't run the makeup water through an R/O filter so a little iron gets left in it.
    Dave J. TFP Moderator
    24' x 52" Round AGP. 2hp/¼hp SPL Power-Flo 2-speed pump. 200sqft Waterway Cartridge Filter. 45MHP2(3GPD) Stenner Peristaltic Pump
    Pool School ----- Pool Math ----- TF-Test Kit

  5. Back To Top    #5

    Join Date
    Mar 2007
    Location
    Coastalish 'down easter'
    Posts
    4,160

    Re: Acid turns yellow when added

    Thank you for the responses!

    The guy I work with said that it looks orange/ red when he adds it (I always turn on the 'aquatreadmills' first and dribble the acid into the strong flow) )

    I've used 2 different brands of MA with the same result. And, I've added both brands of acid to the other pools with no sign of yellow, though they are all chlorine (puck )

    Richard, I think you may be right on the hypobromous acid - the color quickly dissipates. Are there any tests I can run to confirm this hypothesis? (I'm conversant with the scientific method and will do my best to perform any controlled tests you can come up with to support or refute the theory)

    Thank you all for the input!

    (BTW - the lighting doesn't seem to play any roll - Thanks Teapot )
    Luv& Luk
    -Ted

    Having done construction and service for 4 pool companies in 4 states starting in 1988, what I know about pools could fill a couple of books - what I don't know could fill a couple of libraries :-D

    POOL SCHOOL, TF Testkits, Jason's Pool Calculator, CYA vs. cl chart, (Just a few DARNED handy links!)

  6. Back To Top    #6

    In the Industry

    X-PertPool's Avatar
    Join Date
    Jun 2009
    Location
    Exeter, PA
    Posts
    1,385

    Re: Acid turns yellow when added

    Quote Originally Posted by chem geek
    When chlorine is added to a bromine pool (a pool with bromide in it) it can produce so much hypobromous acid locally that some have said it looks yellow (or perhaps it initially produces bromine liquid that looks yellow until it combines with water to produce hypobromous acid). I haven't heard this happening when adding acid, but it's possible that the acid creates more dissolved bromine liquid (Br2) from hypobromous acid (HOBr) though that would be red-brown when concentrated, but perhaps looks yellowish when very dilute. Does the color dissipate after mixing?
    I was going to mention a similar experience. I had a pool that was using bromine tablets through a feeder and I started adding cal hypo through the skimmer. The return lines would shoot out a green cloud. It wasn't yellow but maybe it looked more green because of the blue liner
    -Kevin
    X-Pert Pool Service
    x-pertpool.com
    X-Pert Pool on Facebook and @XPertPoolServic on Twitter
    22,000 gal / 16' x 32' / Vinyl / Hayward s244t /Pentair SuperFlo 1 hp

  7. Back To Top    #7

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

    Re: Acid turns yellow when added

    Quote Originally Posted by waste
    Richard, I think you may be right on the hypobromous acid - the color quickly dissipates. Are there any tests I can run to confirm this hypothesis? (I'm conversant with the scientific method and will do my best to perform any controlled tests you can come up with to support or refute the theory)
    If you notice that the intensity of color when adding acid varies with the bromine concentration and that there is little or no color when there is no bromine in the water, then creation of liquid bromine is the likely culprit here. Thanks for confirming the orange/red appearance as that makes it very likely to be creation of liquid bromine in the water. As this gets more diluted and the pH rises towards the pool average, the liquid bromine will react with water to produce hypobromous acid.
    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"

  8. Back To Top    #8

    In the Industry

    Join Date
    Aug 2009
    Location
    Northern CA
    Posts
    30

    Re: Acid turns yellow when added

    Hypobromous acid...thanks for explaining Richard.

    I have seen this happen in above ground spas, where the elevated bromine levels were giving false high PH readings and acid was mistakenly added. The result was red/orange/brown colored water that did not disapate until soda bicarb was introduced.

  9. Back To Top    #9

    Join Date
    Mar 2007
    Location
    Coastalish 'down easter'
    Posts
    4,160

    Re: Acid turns yellow when added

    To keep this all on the boards:

    Richard PM'd me a few tests to do (which will have to wait a few days before I go to work again and can perform them )

    With the bromine feeder we have (it's a CL 220 for bromine use - i.e. tab fed off line auto brominater) it's proven to be impossible to get the bromine test to show below 10 - you just can't set the dial on the unit low enough to give any less - the pool pump (was) run 24/ 7 per health department 'rules'. [I'm gonna get MY CPO this winter, so I have the 'credentials - I've printed out Richard's "WHAT'S NOT TAUGHT" for myself and the GM]

    When I do the test's, I'll post the results here, so as to advance the 'sum of human knowledge' some
    Luv& Luk
    -Ted

    Having done construction and service for 4 pool companies in 4 states starting in 1988, what I know about pools could fill a couple of books - what I don't know could fill a couple of libraries :-D

    POOL SCHOOL, TF Testkits, Jason's Pool Calculator, CYA vs. cl chart, (Just a few DARNED handy links!)

  10. Back To Top    #10

    Join Date
    Sep 2013
    Location
    ~Stockton, Ca
    Posts
    15

    Re: Acid turns yellow when added

    Last post on this thread is:
    Posted Three years ago and says:
    "When I do the test's, I'll post the results here"

    Hmmm
    Anyone know what the results were???
    400 gal, FGlass spa, 4? HP Waterway TT505 56 pump
    50 sqft Clarathon cartridge filter, Ozone
    K-2005, K-1515, K-1517, LaMotte Insta-Test Borate

  11. Back To Top    #11

    In the Industry

    X-PertPool's Avatar
    Join Date
    Jun 2009
    Location
    Exeter, PA
    Posts
    1,385

    Re: Acid turns yellow when added

    Quote Originally Posted by chem geek
    When chlorine is added to a bromine pool (a pool with bromide in it) it can produce so much hypobromous acid locally that some have said it looks yellow (or perhaps it initially produces bromine liquid that looks yellow until it combines with water to produce hypobromous acid). I haven't heard this happening when adding acid, but it's possible that the acid creates more dissolved bromine liquid (Br2) from hypobromous acid (HOBr) though that would be red-brown when concentrated, but perhaps looks yellowish when very dilute. Does the color dissipate after mixing?

    I've seen this in person with bromine. We took over a pool for weekly maintenance, it had a bromine feeder and we switched to using cal-hypo. Whenever you added a large dosage of cal-hypo to the skimmer it would eventually shoot out a green cloud from the returns (yellow + blueish water and liner). It took about an entire season to finally stop.
    -Kevin
    X-Pert Pool Service
    x-pertpool.com
    X-Pert Pool on Facebook and @XPertPoolServic on Twitter
    22,000 gal / 16' x 32' / Vinyl / Hayward s244t /Pentair SuperFlo 1 hp

Posting Permissions

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