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Thread: Advice on reducing TA and CYA levels

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    Advice on reducing TA and CYA levels

    I'm trying to reduce my TA and CYA levels at the moment. I realise that without draining and refilling this may take some time. If I can do this gradually I would prefer it.

    So I have been vacuuming every other day and refilling about 3 inches each time. This is controlling and reducing small existing algae problem.

    Present levels
    FC 16.5
    TC 16.5
    TA 160
    CYA 100
    PH 7.8 (now 7.2)

    I added some acid tonight and PH now reads 7.2 I have my jets pointing up but they just make large ripples with few bubbles, is this enough aeration to help reduce TA and not increase PH too much ?
    I was thinking of putting a hose in the jet somehow and have it like a small fountain to help this, I do this when filling but thats obviously not long enough, any thoughts ?

    I am happy with the Ph readings, but am a bit worried that it is lower than I am reading it due to the high chlorine level. does a high CYA level help mask this in the test and give an accurate reading or does it only mask the good effects it has in the pool ?

    My TF 100 arrived only last friday and I now feel like I have a good chance if I follow the rules and advice. How long can you maintain higher Chlorine levels and are there any bad longterm affects on my pool from doing this ? I have kept them at the present level since Friday and for the previous 3 weeks it had been a bit of guess work since I found TFP.

    My first tests 5 days ago with the TF 100 showed
    TA 210 -dropped 50
    CYA 100 -no change, but maybe I need more practice with this test ?

    any thoughts or advice would be welcome.

    PS. My fill water reads a TA of 30 so am I thinking this should not be an issue

    Cheers
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    Mod Squad JohnT's Avatar
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    Re: Advice on reducing TA and CYA levels

    I wouldn't be real concerned with the TA at 160. It will put a little upward pressure on your pH, but that's about it. When aerating, the process of reducing TA always raises pH, so you have to stay on top of your pH. Just keeping your pH in the lower part of the range will gradually drop your TA.


    The CYA test is not very accurate at high levels. Yours could be well over 100ppm and still read 100. That's just inherent in all home CYA tests. You can try mixing a pool water sample 50-50 with tap water and testing the mixture. That will read half of your actual CYA level, but it's a rough measurement to just get an idea of where you stand.
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    Re: Advice on reducing TA and CYA levels

    Alfspop, welcome to TFP

    Aeration increases PH without affecting TA, it's the acid additions that lower both TA and PH. So to lower TA and PH you add acid and then to raise PH up via aeration so that your TA remains lower. Given your fill water TA is 30, your TA and CYA issues would continue to benefit from additional dilution. It is very likely your CYA level is greater than 100 and you really want to get it down to around at least 70

    Given your high CYA level, there is very little risk to running an FC of 16-17 as it is well below shock level.

    Edit: John posted before me, but we're pretty much saying the same thing
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    Mod Squad Bama Rambler's Avatar
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    Re: Advice on reducing TA and CYA levels

    First lets straighten out your thinking a bit. Aeration raises pH and adding acid lowers pH and also lowers TA. That's how TA gets lowered. Aeration doesn't do anything to TA, adding acid does. Now that we've got that straight lets move on.

    Since most tests can only read 100 ppm CYA and report anything above 100 as 100, it could be much higher than that. Lets make sure you're doing it correctly.
    Are You mixing equal parts of R0013 and pool water?
    As soon as you start pouring the mixture into the vial the black dot disappears?

    You can pour the mixture back and forth a few times to get a feel for the test. Also since you have such high CYA you can save reagent by only using 5ml or so of R-00013 and pool water. The 14ml of reagent and pool water mix is so you have enough to fill the view tube in case you have very low CYA.

    Removing 3" of water at a time is going to take a long time and a lot more water than draining half the water and retesting.

    ETA~~ And that makes three!!!
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    Re: Advice on reducing TA and CYA levels

    Thanks for the advice on the tests I will try these and see what happens.

    I may be confused on the TA issue, I assumed that I need to aerate, so the Ph rises and I can then add more acid to further reduce the TA. But now thinking that if I do not aerate then I just let the TA take it back up until it finds a balance.

    I am also now thinking the best option is to drain and refill, I think I knew that I just needed someone to tell me.

    Cheers guys appreciated.
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    Re: Advice on reducing TA and CYA levels

    In the presence of FC higher than 10ppm (that's what you have), the pH test is not accurate and will read falsely high. Do not lower your pH further.

    Secondly with a CYA over 100, you will need to hold FC w-a-a-ay higher than you currently are to kill the algae......in the neighborhood of 35+.

    With the above in mind, I suggest you do the drain/refill procedures and get your CYA down around 40-50 before attempting anything else. Disregard the TA issues until you resolve your CYA and get your pool clear.
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    Re: Advice on reducing TA and CYA levels

    will get the refill done as soon as I can - work permitting.

    Cheers
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    Re: Advice on reducing TA and CYA levels

    Ok I have drained half my water and refilled, (Ihave chosen the worst week as I am pretty much 24/7 at work but hey ho) anyway that was April 1st (no jokes please) retested and results were as follows -

    FC 7
    TC 7
    TA 70
    CYA 45/50 (but thinking more closer to 50 to be safe)
    Ph 7.2

    given those readings I took it that the Ph should be pretty spot on, I managed to increase the FC to 20 before heading to work

    back briefly the next day and FC down to 16, brushed and vacuumed to waste and added more bleach ( I am using an unstabilised bleach but in granular form at the moment as that is what I had, this is going to run out tommorrow and i will get some liquid bleach then) FC 24 back to work.

    home today for 5 hours and FC back at 20 so after a vacuum and brush added more bleach, brush, bleach brush bleach back to work for a rest. progress is good and FC today when I left was in the region of 30 I say this as reagent is running low so going by how much bleach i have added and using the dark orange colour result on the OTO TC test.

    I left a further two buckets premixed for my wife to add after dark tonight. I will be home for a couple of hours tomorrow before back to work for another 24. I can then do an overnight FC test to see how I am going. I have a couple of questions please, if any one can help.

    there was a lot of white scale on the pool all the way down, not thick just horrible to look at - can algae get held in the build up making it harder to brush off ?

    we have some dimples (for want of a better word) in the surface of our pool mainly on the horizontals ie floor and steps and it appears that this is where the spots of white (I assume dead algae) seems to be. I think algae gets a film over it so would this explain why it keeps coming back in the same place every time even if it is white and hopefully dying ?

    or is it that the white powder is some sort of residue from the granular chlorine and is just settling in these little dimples and more obvious to the eye than a thin layer across the bottom. Guess i will know the answer when I get some liquid chlorine goin in in a day or so. I notice that it just takes maybe an hour to start to show up in some places on the bottom after adding more chlorine (yes i am disolving, adding it slowly over jets and mixing with brush each time !!!?)

    sorry for my rambling on and questions, but you guys seem to have the answers for most things on this site and hopefully someone be able to help.

    carry on the great work please, its nice to know that there are people out there with a wealth of knowledge and are willing to share it with the rest of us. I am now a reformed pool owner and addicted to this site. brilliant.
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    Re: Advice on reducing TA and CYA levels

    It sounds like things are going fairly well.

    The white patches might be calcium scaling or dead algae. If you touch one you should be able to tell which it is. Algae, alive or dead, will be soft and slimy and will nearly all brush off. Calcium scale will be hard and gritty and will not brush off. If it is calcium you need to get a CH test result to see how bad things are.
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    Mod Squad Bama Rambler's Avatar
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    Re: Advice on reducing TA and CYA levels

    The granular chlorine your using must be Cal-hypo, right?? If it is, you need to get a CH reading so you don't go to high with that. I say that because you don't want any scaling which is what the white substance sounds like.

    ETA -- Jason beat me again!
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    Re: Advice on reducing TA and CYA levels

    The granular chlorine your using must be Cal-hypo, right?? If it is, you need to get a CH reading so you don't go to high with that. I say that because you don't want any scaling which is what the white substance sounds like.

    not sure bama is Cal Hypo a brand name (I have seen it mentioned plenty of times in posts on TFP), this was from a big hardware chain that was the cheapest i could find.

    I did do a CH test when i first got my kit but obviously forgot to post the results with my original set they are at home now but i think they were in the region of around 170 so on the low side. I believe the scaling is from a long term high ph ??? when the pool store were continually telling me to add ph buffer Biogaurd 100 i was forever adding acid but i was not a good pool person then - i am as i said now reformed.

    I did a
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    JasonLion's Avatar
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    Re: Advice on reducing TA and CYA levels

    Cal-hypo is our local abbreviation for calcium hypoclorite, a generic chemical used in many different brands of "shock". Another common form of shock is dichlor, an abbreviation for sodium dichloroisocyanurate, also called sodium dichloro-s-triazinetirone. There are two other kinds of powdered shock you can run into occasionally, trichlor and lithium-hypo, but they are noticeably less common and lithium-hypo would never be the least expensive.

    Each of these chemicals has advantages and disadvantages. Cal-hypo adds calcium, dichlor and trichlor add CYA. Lithium-hypo tends to be quite expensive.
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    Mod Squad Bama Rambler's Avatar
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    Re: Advice on reducing TA and CYA levels

    Look at the ingredients. It should be some percentage of "Calcium Hypochlorite" That's cal-hypo. There is another form of solid unstabilized chlorine and that's "lithium Hypochlorite" but that's crazy expensive. If it's got Di or Tri in the name, it's stabilized.

    Dangit, Jason beat me again! He's good at that!
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    Re: Advice on reducing TA and CYA levels

    Yes he does seem to be pretty quick off the mark,

    Ok cheers boys I will check that out, I have only been using it for about three weeks and it is going to run out as i say v v soon. prior to that i have been using swim clear which is stabilised and is the reason that i had such high CYA readings. Thats history now, no more pool shop advice for me.

    will be going liquid and i will report back. am sure it was high Ph as it has been there for some time just didn't realise it went all the way down till i drained it the other day.

    so could the white powdery stuff be just some undisolved calcium from the chlorine, forgot to mention an interesting but probably very valid point. when i did my refill the pool took 24 hours to fill (as my wife turned it off when she went to bed as to avoid over filling) anyway 24 hours with no pump running, just the hose, lower CYA and FC of 7, there was a sparkling pool with no white spots or patches on the bottom. after i did my tests i started adding Cal hypo ?? and within 2 hours there was white spots appearing across the pool. algae or some sort of residue ???

    Thanks again, quick rama see if you can beat jason
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    Re: Advice on reducing TA and CYA levels

    quick update

    got a couple of hours this morning after getting some 10% liquid bleach. to cut to the chase I played around with the white stuff not slimy or gritty just a bit powdery is the best I can describe it. I added 3 ltrs of bleach and then thought maybe i should add some acid so put in 3/4 ltr (as my TA is still a bit high) and assumed my Ph may have climbed a bit over the last few days.

    not sure if that was right as it was a bit of a guess but within 10 mins my pool had gone from cloudy water to clear water. (only went cloudy after I really dosed it up yesterday with the Cal Hypo (yes I read the label today and that is what it is, thanks for explaining that one to me guys), took the readings below, and by the time I left for work there was much less of the white powder, and clear clean water.

    TC - dark orange, I'm trying to save my reagent for overnight test tomorrow
    TA - 90
    CYA - 50
    CH -150 it had been 120 lower than I remembered

    would I be right in thinking that if the Ph had crept up the Cal Hypo would not have disolved properly, hence the white stuff, or am I way off.

    anyway my pool looks brill, I am going home tomorrow arvo to hoover any residue up and do an over night FC test. I feel that any algae should be dead and am in great spirits about the whole pool thing.

    love the TF 100 and this forum, thanks.
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    Mod Squad Bama Rambler's Avatar
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    Re: Advice on reducing TA and CYA levels

    The OCLT is a good thing to try now. Sounds like you're on the right track.
    Go ahead and post the rest of the test results while your at it.

    pH
    FC =
    CC =
    TA = 90
    CH = 150
    CYA = 50

    If the FC is higher than ~15 then don't worry about pH until it comes down to 10 or below.
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    Re: Advice on reducing TA and CYA levels

    Quote Originally Posted by Bama Rambler
    The OCLT is a good thing to try now. Sounds like you're on the right track.
    Go ahead and post the rest of the test results while your at it.

    I will do tomorrow unfortunately I'm back at work till tomorrow afternoon. My original readings after drain and refill were

    Ph 7.2
    FC 7
    CC 0
    TC 7

    I am hoping the FC will be in the region of 20 - 25 given the dark orange result from the OTO Chlorine test. I really am low on R-0871 so trying to save it for my OCLT. My CC have never reached 0.5 by the way.

    given that my FC is relativly high and it states in the extended kit instructions that you may add another dipper of R-0870, would the FAS-DPD test work if I just used 5mls and one dipper, or would that give really way off results.

    I know I keep saying it but thanks once again.
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    Mod Squad Bama Rambler's Avatar
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    Re: Advice on reducing TA and CYA levels

    Using 5ml's for the FC test would be too course for the OCLT. If you're that low on reagents I'd go ahead and order some and wait till they get there to do the OCLT. You don't want to run out in the middle of the morning test.

    You can dilute the sample of pool water with chlorine free water to get a estimate with the OTO kit. It suffers precision but it's usually good enough for keeping it at shock level. There's instructions here that tell you how to do it.
    Dave J. TFP Moderator
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    Re: Advice on reducing TA and CYA levels

    Ok cheers Dave, I guessed it wouldn't work as it was not mentioned but thought I would just double check.

    I should have enough for the OCLT and I will post the results Thurs morning.

    If all goes well I will just let the FC drop until its in the right zone by which time replacements should have arrived.

    Thanks
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    Re: Advice on reducing TA and CYA levels

    OCLT completed this morning and it was FC 19 last night and this morning with no CC

    However I did notice a couple of spots where it has predominantly shown up forever (not sure dead or alive) so have continued at shock level and will continue with brushing and shocking over the weekend. My eldest has a party in 2 days time so it will get used heavily that day for sure. After that I would hope to start to bring the FC level down a bit.

    An earlier question that did not get answered was - is it ok for the kids 9yrs to go in whilst at shock level of around 20. If someone could let me know I will rest happy or let FC drop to a safe level till after the party.

    I have started to raise the CH level to around 260 but will do this gradually, I read somewhere that low CH may aid algae production.

    Just as a footnote my wife's friend came around yesterday afternoon and commented unprompted on how sparkly and great the pool looks and she is now looking forward to the weekend for a swim.
    All thanks to you peeps on TFP

    One last question that I have been unable to find the answer to is - assuming that and taking it as a rough guideline that a pool loses 3ppm of Ch per day (dependent upon sun and algae). does this rate speed up or slow down with higher levels or does it stay constant regardless of the FC level, Hope I explained that clearly - I know what I mean anyway

    Thanks again
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