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Thread: Muratic Acid

  1. #1
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    Muratic Acid

    Hi,

    I have been working on an algae, cya problem for 2 weeks. I had a party Labor and all the "experts" who think they know everything said add muratic acid to the skimmer. Another said add soda ash. I know all theses things are relevant to a specific problem and will cause a different problem if it is not there now.

    We have added bleach and bleach and bleach. Ph is about 7.2, ta is 110, cya is 60, chlorine right now is pegged on the kit I have. I have ordered a more specific kit for higher chlorine levels but it's not here yet.

    What is muratic acid actually used for? My pool surface already needs resurfacing so will it hurt it?

    Thanks

  2. #2
    Senior Member sammm's Avatar
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    As far as I know, Muriatic Acid is only for lowering PH levels. There may be other things, but I'm still learning.

    According to Chemgeek's Chlorine/CYA chart ---> http://troublefreepool.com/sticky.php?s=2346

    You'll need to raise your FC level to 23.7 to shock your pool and hold it at that level for 24 hours to kill off your algae.
    WetEdge Satin Matrix, 16K gallon, Pentair NSP-60 DE filter, Pac Fab Challenger, 2HP pump, BBB, Polaris 360

  3. #3
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    Oh dear! I don't know what those "experts" were thinking. Looking at the numbers you've given, you don't need muriatic acid added at this time, at all.

    Muriatic acid is used to lower pH and TA - your's are perfect for now. If your pH goes up too high, you use MA to lower it.

    I personally, would never add MA to the skimmer basket. I drizzle it around the pool about a foot out, or sometimes just pour it in one spot about a foot out from a return. Your pump should be running when you do this.
    Buggs

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  4. #4
    Senior Member The Mermaid Queen's Avatar
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    sammm, (and JoeDeb)
    shocking is not a one day event, especially if you are in the midst of an algae bloom.

    You need to get your pool up to shock level, and keep it there until these three things occur:

    1) your FC holds overnight (max of 1ppm loss)
    2) you have 0 cc's (max of 0.5)
    3) your water is clear and sparkling.

    check a few times daily and boost your FC level back up.

    Until your better test kit arrives, you can increase the level your test will 'read' by using the dilution method... Get some distilled water or bottled drinking water. In a clean container, measure 2 parts distilled water and one part pool water. Use this to fill your test cell. Add reagent as usual, and multiply your result by 3. If you need to, you can use 3 parts distilled water and multiply results by 4. This is an inaccurate method at best, but better than guessing!

    18x32 grecian IG vinyl; ~23000 gallons; 250# sand filter, Hayward superpump with AO Smith motor 1HP SF1.0; booster pump for polaris. Handy Links: Jason's Calculator, TF-100 Test Kit, Pool School, CYA-Chlorine Chart
    "Shock" is a process, not a product!

  5. #5
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    Muratic acid

    Hi,

    When I said "experts" I meant "know it alls" who have had pools, etc. They were all in the pool and discussing different methods to shock it. One guy in charge of maintaining an olympic size pool but it had chlorine gas equipment...different ballgame there.

    I have been adding so much chlorine for two weeks and it's not helping...also drained a third of the water. My cya is now about 90 even after draining and haven't used stablized chlorine since draining. Clorox only. I added 8 gallons last night and the level looked really high. I guess I should add 12?? Then 12 more the next day and 6 at night if necessary right. It's hard to get my head around that! But we have been doing it.

    My sides need resurfacing too...If I have to drain it again I am going to resurface it.

    Do you think a salt chlorine generator will help?

    Thanks

  6. #6
    Senior Member The Mermaid Queen's Avatar
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    Maybe a new set of test numbers is in order so we can better assist you... you said in the first post that your CYA is 60, but now you say it is 90... either one is a manageable number, but you will need more to use more bleach for the free chlorine to be effective.

    What is your Chlorine level? did you try the dilution method? If you do not consistently keep your FC up to shock levels for long enough, you are fighting a losing battle. You shock, and some of the stuff dies, but then the Cl levels drop, and the algae can get going again. You need to test frequently and add bleach to reach shock levels. You can beat this thing with a lot of bleach and some patience and persistence!!

    An SWCG is a handy method of chlorinating your pool, but you still need to test your water. You will need to adjust your pH down with acid when using an SWG. It does keep you from lugging jugs, and it gives you a cushion... if you forget to test and add bleach for a couple of days, you may get an algae bloom. Not so with an SWG.

    18x32 grecian IG vinyl; ~23000 gallons; 250# sand filter, Hayward superpump with AO Smith motor 1HP SF1.0; booster pump for polaris. Handy Links: Jason's Calculator, TF-100 Test Kit, Pool School, CYA-Chlorine Chart
    "Shock" is a process, not a product!

  7. #7
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    Muratic

    Oh...cya number was a typo I guess. It was over 100 when I started this process. I drained about 1/3 of the pool but were too chicken to drain it further as pool damage is very common here in Houma, LA. Water level in the ground is very high and they come out of the ground on regular basis. Horror stories abound!

    I think if we have to bring the level down more we will have it resurfaced.

    Will the swcg put enough chlorine in if my cya level is too high? Can it be adjusted to put more out? I don't know anything about them and I am trying to do a bit of research before I buy one.

    Thanks

    ph 7.4
    ta 110
    ch (over 5 can't test higher yet)
    cya 90
    cal/har 500
    25,000 gal gunite

  8. #8
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    I have a Goldline SWCG and have not had to physically add any chlorine since my initial start-up. Current testing shows my FC at 3.6 with 0 CC. The ideal range for FC according to the manufacturer is 1.0-3.0. Ideal range for CYA is 60-80 ppm. I'm trying to bring up my CYA from 40 to the ideal range. I guess SWCG requires a CYA level a bit higher than other methods of chlorination.
    20K inground gunite w/ Aqua Logic automation and chlorination Sta-Rite 400 K natural gas heater and cartridge filter 2 HP pump 1.5 HP spa bubbler for spillover spa 1 HP dedicated Letro Legend cleaner
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  9. #9
    Senior Member The Mermaid Queen's Avatar
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    Re: Muratic

    Quote Originally Posted by joedeb
    Oh...cya number was a typo I guess. It was over 100 when I started this process. I drained about 1/3 of the pool but were too chicken to drain it further as pool damage is very common here in Houma, LA. Water level in the ground is very high and they come out of the ground on regular basis. Horror stories abound!

    Understand... I used to live just up the road from you in St. Charles Parish!

    I think if we have to bring the level down more we will have it resurfaced.

    Will the swcg put enough chlorine in if my cya level is too high? Can it be adjusted to put more out?

    SWG's need a higher CYA level than non-SWG pools. Like flintstone said, usually 60-80, as opposed to the 30-50 recommended for non-SWG pools. They are adjustable, and can even be set to superchlorinate (shock) although most here just use bleach when/if they need to shock. Shocking with the SWG causes the lifespan of the cell (inner workings of the SWG) to be seriously reduced. Most find regular shocking unnecessary anyway!

    I don't know anything about them and I am trying to do a bit of research before I buy one.

    Thanks

    ph 7.4
    ta 110
    ch (over 5 can't test higher yet)
    cya 90
    cal/har 500
    25,000 gal gunite
    Try the dilution method to test your chlorine. My guess is that you're not getting nearly enough in there to kill your bugs. "over 5" is simply not accurate enough to be of much help.

    Is your fill water extremely hard? I ask because your CH is high, especially since you just did a partial drain/refill, but I don't know enough about CH to give advice... You've more pressing problems, anyhow!

    18x32 grecian IG vinyl; ~23000 gallons; 250# sand filter, Hayward superpump with AO Smith motor 1HP SF1.0; booster pump for polaris. Handy Links: Jason's Calculator, TF-100 Test Kit, Pool School, CYA-Chlorine Chart
    "Shock" is a process, not a product!

  10. #10
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    CH Level

    Hi,

    The water doesn't seem hard at all. The pool surface is so oxidized that a pool guy said there probably was a calcium hardness problem. Is there a way to bring it down or is draining water the only way.

    Yesterday we went outside and it looked terrible again. Could barely see the drain. We went and bought 10 of the big bleaches....should we have put them all in? How many does it take to get the chlorine high enough? We put in 7 when we got home and it went sky high on the reading. This morning there was barely any in there so I put in a bunch more. I will check the levels all day and keep adding but I have been doing this for 2 weeks. I must be doing something wrong.

    I guess if you put in 10 and then just put in 10 again and again until it clears up. I have never seen anything like this. When we used the granules it would shock it but it would come right back because the level of the cya is so high I guess.

    The pool guy was changing our light and he looked at the algae on the walls and said "You won't win that battle". I guess he was right. It isn't that slimy green algae--when this first started the water was crystal clear but the whole pool looked green. The algae looks yellowish brown when we brush it off and then it seems to settle right back on the walls. Sometimes you can feel slime on the walls but we have gotten rid of that for now. It is just yellowish/greenish/brownish clinging stubborn stuff.

    One more thing....should I turn off the pump and let it settle? It runs 24/7 and always has since we moved here. If we didn't it would turn green so fast it's pitiful. The Polaris is running around...should it be off instead of stirring it up? If it settled maybe we could vacuum some of it out....??? Thanks

  11. #11
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    I guess if you put in 10 and then just put in 10 again and again until it clears up.
    Actually, that's pretty close. It is a constant process rather than a one time event.

    You need to add enough chlorine to your pool to get to 20+ppm......it will immediately begin to be used up killing the algae so you must add more chlorine....two or three times daily is best....brining the total right back up to 20+ each time you test.

    If you hold it there long enough, vacuum and brush frequently, and run your pump 24/7, your pool will clear.
    Dave S.
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  12. #12
    Administrator JasonLion's Avatar
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    It can be diffcult to get high calcium levels down. If your fill water is reasonably low in calcium, replacing water is your best option. If your fill water is high in calcium you are kind of stuck unless you live in the greater Phoenix metropolitan area and can use Calsaway.

    You can use my Pool Calculator, see the link in my signature, to figure out how much bleach to add to get to any given FC level.

    It is possible to beat mustard algae, which is what it sounds like you have, but it will take some work. The key is to get the FC level up very high all at once and recheck and bring it back up several times a day for a couple of day. With a CYA level of 90 you will need to bring your FC level up to 50, or higher, and hold it there for a few days while brushing the wall reguarly to defeat mustard algae. That would be twenty gallons of bleach to start, and plenty more to hold the level. It might be more practical to lower your CYA level a little first, which will reduce the FC level you need to aim for.

    If you don't go all the way up to shock level and frequently retest and restore the FC level you are essentially wasting your time. The algae gets beaten back but grows right back when there is a moment of lower FC level. You really need to tackle it all at once. If you don't kill all of the algae all at once then nothing is really going to help. You might get the pool a little clearer on one day only to have it go back to looking bad the next day.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
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  13. #13
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    Hi,

    This may be a silly question but we still don't know much.

    While we are are experiencing this algae problem should we divert more pressure through the skimmer by partially closing the main drain. We have a lever for the skimmer and a lever for the main drain. We closed the main drain a bit and the skimmer seemed to be more forceful.

    Another stupid question...we have the stabilized chlorine tablets floating even though our cya level is high. I know they are making it stay high but you can always tell when they are used up because the pool starts to get cloudy. One hundred percent of the times when the pool has started to become hazy it's because those pucks are used up. We are no longer using granules...just clorox. Should we stop using these?

    Our kids are coming this weekend and I guess they will not be able to swim. I am too afraid of 50 gallons of clorox over a 10 day period. Still cloudy. Adding it 3 times a day and now Walmart doesn't have anymore clorox!! We bought it all...

    Thanks again for all your advice...

  14. #14
    Administrator JasonLion's Avatar
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    The mix of skimmer and main drain doesn't make any difference to the algae. Ideally you should be able to have them both on and still get reasonable flow from each one. The only times to change that would be if you are vacuuming (turn off the main drain), or lowering the water level below the skimmer (turn off the skimmer).

    Using stabilized chlorine will continue raising the CYA level and make it even more difficult to get rid of the algae. The tablets don't just keep the CYA high, they make it go higher.

    As long as you have algae you will not be able to maintain a safe chlorine level and the pool is not safe to swim in. You either need massive amounts of bleach all at once or replace a lot of the water to bring down the CYA level and then use large amounts of bleach all at once. How clear or cloudy the water is while you still have algae doesn't really make any difference. If you haven't killed all the algae the pool is not safe to swim in.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
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  15. #15
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    Muratic acid

    Hi,

    Do you mean it's not safe because of the chlorine level or because of the algae itself. Also, thanks for the lesson on the filter/pool drain/skimmer. We just thought it may suck the algae through the skimmer faster or with more force...

    We have learned more from you in a week than over the last two years. The pool is actually getting sparkly.

    Deb

  16. #16
    Administrator JasonLion's Avatar
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    When there is algae, the water right near the algae won't have any chlorine left. Any chlorine around the algae will go to attacking the algae lowering the chlorine level in that part of the pool. No chlorine means that viruses and bacteria can live in the water near the alage thus create unsanitary/unsafe conditions.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
    TFP Admin. Creator of PoolMath and Pool Calculator. Other handy links: Support this site, TF Test Kits, Pool School

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