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Thread: CYA eating monsters

  1. Back To Top    #1

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    CYA eating monsters

    I just got all the pool equipment hooked up and added the 5000 gallons of water I needed to bring the pool back up to the middle of the skimmer and the best news ever is (so far, knock on wood) NO EQUIPMENT ISSUES THIS YEAR!!

    That's where the good news ends though. My water is slightly green (most people would just say "green", but after last year, I'm going with "slightly green.")

    My number are:

    FC - 0
    CC - 0
    TC - 0
    pH - 7.2
    T/A - 90
    CH - 80
    CYA - 0
    NH - 4
    Temp - 51 (Brrr!!)

    Last year I had no CYA when I opened and about 4ppm ammonia, so at least I know what I'm up against. But I got it to a nice sparkling blue last year and I know I can get it there again this year. Not having to do a lot of plumbing, rebuilding a pump then having it fail again and buying a new pump will be a nice change.

    My pool ate CYA all year last year (I felt like I should have just used pucks!!) I'm assuming that even though my pool was nice clear blue and sparkly, whatever bacteria eats CYA was hanging in there. I know I added enough CYA over the course of the year to bring it to 150, but could barely maintain 30 whenever I tested it (after waiting a week and all that. I never added enough to try to hit 150 ppm at once!!) This year, I'm planning to hold shock level a little longer after I'm "done" shocking and see how that goes. I'm still learning, but I loved how much less I spent on pool chemicals last year (so I could spend it on pool equipment instead.)

    Friday is "Go clean Sam's out of bleach day." Get there early!! Actually, I'm going to start with 5 cases of the 3 bottles that are 6% and 182oz jugs. It's a start. I get to go back and read my old posts and see if I can figure out how many bottles I used last year. Should be close.

    Good luck to all those opening this time of year!!
    32x16 ft Grecian rectangular vinyl pool 8ft on deep end - 19000 gal. 18" Hayward S-240 sand filter. 250K BTU Pentair MasterTemp heater. Hayward 3/4 HP Super Pump.

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    JasonLion's Avatar
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    Re: CYA eating monsters

    Great attitude

    Do you have an autofill system? When there is a slow leak with an autofill system you may never notice the leak but your CYA level goes down as water gets replaced.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
    Creator of PoolMath and Pool Calculator. Other handy links: Support this site, TF Test Kits, Pool School

  3. Back To Top    #3

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    Re: CYA eating monsters

    No autofill and wasn't regularly adding water (due to splashout or evaporation.) The best I can tell is the bacteria or whatever it is that likes the taste of CYA. We'll just have to see what this year brings. All I added last year was CYA and bleach. If that's the worst that happens this year, I'll by a happy guy.

    Thanks for checking up on it!!
    32x16 ft Grecian rectangular vinyl pool 8ft on deep end - 19000 gal. 18" Hayward S-240 sand filter. 250K BTU Pentair MasterTemp heater. Hayward 3/4 HP Super Pump.

  4. Back To Top    #4

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    Re: CYA eating monsters

    Are you sure your CYA test is working? I'm not sure what the shelf life of the reagent is but maybe the test is not valid.
    Free-form concrete walls with vinyl liner, 18,000 gallon capacity, Jandy 1.5HP e-Pump, Jandy DEV48 DE filter (using cellulose media), Jandy AE2500 heat pump, Jandy Aqualink Power Center with 14-blade cell kit and Jandy PDA-P8 wireless control system.

  5. Back To Top    #5

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    Re: CYA eating monsters

    Quote Originally Posted by poolneophyte
    Are you sure your CYA test is working? I'm not sure what the shelf life of the reagent is but maybe the test is not valid.
    It's possible, but I doubt that the reagent is expired. Because CYA reagent usually get used up pretty quick as it takes a lot to do the test, it generally doesn't sit around long enough to go bad. That, and the fact that he had the same thing happen last year all points to this being a repeat event.
    10K gallon IG gunite with waterfall; Pentair CC320P filter; WhisperFlo 2 HP pump
    TF Test Kits - Pool Math - Pool School
    "It depends."- JohnT

  6. Back To Top    #6
    frustratedpoolmom's Avatar
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    Re: CYA eating monsters

    What brand of CYA were you using? What was the % strength of CYA? (I once accidently bought and added CYA That was only 50%...didn't realize it till I noticed that I didn't reach my goal.)
    Helpful links: Pool School; CYA/Chlorine Chart
    24' round AG pool, 52" high, Raypak heater; Waterway 2 spd Pump;
    150 Sq ft. Clearwater Cartridge Filter; Former and DISSATISFIED "Pool Frog" owner
    http://www.PerfectlyClearPoolService.com

  7. Back To Top    #7

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    Re: CYA eating monsters

    I'm pretty confident about the CYA test. My reagent is from late last season (ordered it from TFTestKit site probably in Aug. or Sept.) And I tested CYA so often last season, I got pretty good at the test too!!

    Last year I was using BioGuard's Stabilizer 100. According to the MSDS it's 100% CYA.

    I'd be interested to find out if anyone has any suggestions on what to do to get rid of bacteria. I'm pretty sure shocking it is the answer, but I don't know if it's more resistant to shock like mustard algae or if the standard "test" for being done shocking applies (ie. >1ppm FC loss overnight, >.5ppm CC, etc.) Last year, I met the requirements for being "done" shocking and the pool was nice and blue, but I kept losing CYA.

    I'm going to keep close track of my CYA this year and report on here, but if anyone has any experience or thoughts, let me know.
    32x16 ft Grecian rectangular vinyl pool 8ft on deep end - 19000 gal. 18" Hayward S-240 sand filter. 250K BTU Pentair MasterTemp heater. Hayward 3/4 HP Super Pump.

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    Re: CYA eating monsters

    Quote Originally Posted by loughps
    I'd be interested to find out if anyone has any suggestions on what to do to get rid of bacteria. I'm pretty sure shocking it is the answer, but I don't know if it's more resistant to shock like mustard algae or if the standard "test" for being done shocking applies (ie. >1ppm FC loss overnight, >.5ppm CC, etc.) Last year, I met the requirements for being "done" shocking and the pool was nice and blue, but I kept losing CYA.
    Unless the bacteria were in biofilms, say in your sand filter, it is unlikely that there were living bacteria eating the CYA since it takes a very low level of chlorine to kill most bacteria. Nevertheless, it is certainly possible to have some channeling in a sand filter such that bacteria aren't exposed to very much chlorine, then form biofilms, and can then grow relatively protected and could convert CYA into ammonia (i.e. use the CYA as a lovely source of nitrogen) more slowly than in a pool with no chlorine at all. This is just speculation, but your approach to shock the pool is part of the solution. The other would be to check the sand filter for channeling and fix it as needed (see this Pool School article).
    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"

  9. Back To Top    #9

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    Re: CYA eating monsters

    Thanks for the info. I replaced the sand in my filter at the beginning of last season or the end of the previous season, so I doubt I had channeling last year. I can check it again later this year, but I will admit I'm not looking forward to taking all those bolts off of the top. I guess this weekend is probably a good time though since I've only had my system on recirculate, so there's no water in the sand filter right now.

    That's good to know about low levels of chlorine killing the bacteria. There is a drain at the deep end of the pool and one skimmer in the side of the pool. There are two eye returns, one at each end of the pool and I get a good circular flow from those, so I don't think I have any dead spots that the chlorine isn't getting too. I'm going to work at keeping good records on my CYA levels and when I backwash or add extra water to the pool. I'm pretty sure my CYA loss wasn't due to dilution, but I didn't keep good enough records that I can prove that.

    I really shouldn't be too concerned. The pool looked awesome last year. I guess now I want it all.
    32x16 ft Grecian rectangular vinyl pool 8ft on deep end - 19000 gal. 18" Hayward S-240 sand filter. 250K BTU Pentair MasterTemp heater. Hayward 3/4 HP Super Pump.

  10. Back To Top    #10

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    Re: CYA eating monsters

    YUCK!! So, I opened the sand filter. It wasn't channeled, but there was a good bit of junk still in there from last year. I followed waterbear's suggestion from the other post and put a hose in there and stirred it a lot with my hands (I'm too scared of breaking a lateral to use anything else.) While stirring it, I could tell there were some areas that were more packed than others. I'd pull up a handful that looked more like a ball of dirt than sand and STINKY!!

    I ran water in it until it was overflowing and then stirred and kept the water going for over a half-hour and never got close to clean. I put the top back in place for the night and I'll start again tomorrow.

    I'd like to just switch the sand to zeolite (need to read more articles first though). But the biggest problem with that is that I do the pool, my wife does the budget. She gets the last say and I'm pretty sure it's going to be "No." But I'll get it as clean as I can and if it wasn't the problem, at least I'll know it's in good shape.

    Now I gotta read up and see if I want to try to make a case for 150 lbs of zeolite or just keep cleaning the sand that's in there.

    Thanks for the idea ChemGeek!!

    [EDIT]OK, just a little reading tells me my interest in zeolite may be overrated. Probably not going that route, but doing LOTS more research if I do.[/EDIT]
    32x16 ft Grecian rectangular vinyl pool 8ft on deep end - 19000 gal. 18" Hayward S-240 sand filter. 250K BTU Pentair MasterTemp heater. Hayward 3/4 HP Super Pump.

  11. Back To Top    #11
    New2Me's Avatar
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    Re: CYA eating monsters

    When I first got this pool I had persistent problems with algae, do to ignorance on my part. It would appear clean, but used a LOT of chlorine. When I went to change the sand, I had to scrub the top inside of my sand filter, it was coated with a layer of "biofilm?" that was a green color.
    I think that any time you have algae in the pool, it would be a good idea to clean out the filter area above the sand bed(or the whole thing if it looks like it needs it,) to remove the stuff. It is not as easy as brushing down the walls/floor of the pool, but may help prevent algae return. The pool's chlorine demand dropped after that.
    I also take out the light to clean it on the back side, as well as cleaning the bottoms of the ladder steps and the wall bumpers. You should pretty much try to at least inspect, if not clean, anything that is wet.
    After the sand change, while I was using 5% liquid chlorine, I also took to slowly pouring it in the skimmer so that the filter would get a strong dose. Last year I used a SWG, (augmented with LC when needed) to maintain a healthy FC, never had any CC above 0.5, no signs of algae, steady minimal chlorine demand, 50 ppm borates. This week, when I inspected the filter I again had a "film" on everything above the sand bed that I was able to easily wipe off and dis-infect. i don't remember seeing it last fall, but everything was wet, and it was cold and damp out, too, so I may have missed it, or it just may have "grown" over the winter.
    Anyway, when you go to clean up after algae, clean everything!(Toys & tools too!)
    Good Luck, and Best Wishes!!!
    22 x 40 IG vinyl lined, 23,570 gal.
    1 hp. Pac-Fab Challenger pump 300# sand filter
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  12. Back To Top    #12

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    Re: CYA eating monsters

    Just a progress report.

    Friday
    Filter on recirculate
    7PM - Added 10 ppm chlorine
    Added 4lbs CYA targeting 20ppm via sock in front of return

    8PM - Test
    FC - .5
    CC - 3.0 (No typo here)
    Added chlorine to target 10 ppm again

    9PM - Test
    FC - .5
    CC - 6.0 (Nice number, but upside down)
    Added chlorine to target 10 ppm again

    1030PM - Test
    FC - 6.5 (Woo hoo!!)
    CC - 1.0
    Added chlorine to target 10 ppm again (a theme, I know.)

    12AM - Test
    FC - 9.5
    CC - 1.5
    Went to bed.

    Saturday
    8AM - Test
    FC - 8.0
    CC - 1.0
    Added chlorine to target 10 ppm again.

    Pretty happy with numbers, so I switched from recirculate to filter. Planning on testing every four hours now (I'm low on FAS-DPD powder until my order gets here.) Since I just switched to filter, I'm going to check that hourly (only going to backwash at 8psi increase.)

    Before I put my sand filter back together, I backwashed it a little with the top off because cleaning the water with a hose wasn't getting me anywhere. Got it much cleaner that way and added some bleach directly to the water in the filter and mixed the sand up good (or at least think I did.) I drained it from the bottom drain to try to move the bleach through the sand bed. There wasn't any kind of film on anything above the sand bed, but hopefully all that work in the sand will help the problem I was having last year.

    I'm going to try to keep an eye on how much I backwash since I'm hoping to get a handle on my CYA this year.
    32x16 ft Grecian rectangular vinyl pool 8ft on deep end - 19000 gal. 18" Hayward S-240 sand filter. 250K BTU Pentair MasterTemp heater. Hayward 3/4 HP Super Pump.

  13. Back To Top    #13

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    Re: CYA eating monsters

    Latest info:

    The pool is getting much clearer by the day. I'd definitely call it blue now, but it's still cloudy. I haven't bothered with an overnight FC loss test yet because I plan on shocking until Friday no matter what. Then I'll try an overnight test and see if I want to hang in there a little while longer (assuming the test says I'm "done.")

    I'm trying to keep an eye on the amount of water I use backwashing and rain brings so I can determine if my CYA loss is really all in the backwashing, or if there might have been something in the sand filter eating it up, or if something else is going on. Time will tell.

    I've backwashed three times and based on the flow rate of the filter and the water meter reading to bring it back up to the mark on the skimmer, I use about 300 gallons for backwash (about five minutes with a one or two minute rinse factored in.) So I've "added" (and drained) almost 1000 gallons since adding my CYA less than a week ago. (I used the Wal-Mart HTH stabilizer in a sock in front of a return.) Two days ago I tested my CYA because that's all the longer I could stand it and I could still make out the dot at 20ppm (but just barely, so I know there's some in there). I'm not going to really bother keeping a close eye on it until I get more in there (which I'm not doing until I finish shocking.) Hopefully I'll get a more steady number this year, or be able to correlate the loss with the backwashing.

    On a sad note, my equipment luck ended today. I noticed a small amount of water under the pump and on closer inspection, sure enough, the shaft seal is going. Last year, I had a one year old Hayward Max-Flow that I bought online (new, but didn't have the warranty info, nor want to be without a pump while I sent it away) that went through 2 shaft seals before I decided to have the local pool store install the pump they recommended (the 1 HP Hayward Super Pump in my sig.) A few weeks after they installed it, the shaft seal started leaking and instead of replacing it, they replaced the pump (they thought it was a manufacturing defect with a lot of motors they had.) Went the rest of the season without any issues. Opened the pool with the new pump this year and less than a week later, the shaft seal is leaking. The local store needs to order some seals and they'll be out Monday.

    What the heck?! Anyone had a similar experience? I wish I had gone with a different brand of pump at least now. For now, I'm at the mercy of the warranty. I don't want to spend money to replace it again while the store will still fix it for free. Still bummed though.

    Only doing FC/CC test while shocking (with the occasional pH check for comfort):
    FC - 11.0
    CC - 0.5
    TC - 11.5
    pH - 7.2 (only test it every few days since I'm above 10ppm chlorine. Aerating to bring it up some since I plan on adding CYA when I'm done shocking.)
    32x16 ft Grecian rectangular vinyl pool 8ft on deep end - 19000 gal. 18" Hayward S-240 sand filter. 250K BTU Pentair MasterTemp heater. Hayward 3/4 HP Super Pump.

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