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Thread: slam question

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    elainerader's Avatar
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    slam question

    Long story.....now my pool has mustard algae.

    I ran full tests, these are my numbers:

    CL 5
    CYA -0- !!
    TA 50
    PH 8 !!

    I know I need to lower my PH to 7.2, I have the dry acid and I'm ready to lower it BUT notice my CYA levels, they are -0-.
    My question is do I have to raise my CYA levels before I can effectively slam?? I know raising the CYA level would also lower my PH. My problem is I cannot find any cyanuric acid locally, and the only place to buy pool chems around here does not stock them this time of year. (walmart)

    So.....can I just adjust my Ph and ignore my CYA for now or would the slam not work?

    Thanks
    25K GALLON IG VINYL
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    Texas Splash's Avatar
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    Re: slam question

    Greetings! I would be hesitant to go into SLAM mode without any CYA at all The reason being is that CYA not only protects your FC from the sun, but it also serves to protect you and your pool from the chlorine. When a pool has no stabilizer (CYA), the strength/effects of FC are significantly increased. I understand your concern about Wal-Mart not stocking stabilizer. What about ordering on-line? Have you tried Home Depot or Lowe's? Also, can you confirm please what test set you used to test your CYA?

    As a note, CYA (stabilizer) shouldn't have any effect on your pH. Muriatic acid will lower your pH. Hope this helps.
    Pat (a.k.a. Texas Splash) ~ My Pool: Viking Fiberglass; 17,888 Gal; Waterway Supreme 2-sp/2-hp pump; Hayward Ctg filter; TF-100 w/ Speed Stir
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    elainerader's Avatar
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    Re: slam question

    Hi and thanks for getting back to me!! I've been waiting to hear from someone before ordering on line from amazon. So now I will do that!

    I use the Taylor test kit that has all the tests.....the CYA Reagent R-0013 is about three years old, would that make a difference when testing? I tested at the beginning of the season and my CYA was 40, just as it has been for three years without ever adjusting it. What would make it change so drastically?

    Thanks again for your help!

    Note: I thought I read somewhere that raising CYA levels would lower Ph....of course now I can't find where I read that!
    25K GALLON IG VINYL
    LASER SAND JACUZZI FILTER #250L 66GPM JACUZZI 1.0 HP PUMP
    UNDER WATER LIGHT
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    Texas Splash's Avatar
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    Re: slam question

    The primary way CYA drops is from water exchange (i.e lots of storms/heavy rain, backwashing a lot, etc). Some folks will see a change in CYA if they allowed their FC to drop to zero, thereby allowing the pool to introduce an ammonia conversion into the mix. But it's not common for CYA to just stay in one place for a very long time - season after season. It usually needs a little adjusting each year. As for the age of your reagent, 3 years is a long time. If it was maintained in a cool place out of the sun it may still be fine, but since you look like a SLAM is in your future, you may want to consider ordering some fresh reagents for the SLAM. Definitely make sure you have stabilizer in the water before increasing the FC real high for a SLAM. For now, until you can get the stabilizer, if you're sure you CYA is zero, just keep your FC around 2-3ppm.
    Pat (a.k.a. Texas Splash) ~ My Pool: Viking Fiberglass; 17,888 Gal; Waterway Supreme 2-sp/2-hp pump; Hayward Ctg filter; TF-100 w/ Speed Stir
    Vital Links: POOL SCHOOL, RECOMMENDED LEVELS, RECOMMENDED CHEMICALS, Poolmath Calculator, SLAM, Chlorine/CYA CHART.
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    elainerader's Avatar
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    Re: slam question

    Thanks for all the explanations! I did have to add a lot of water this year due to high heat, and drought conditions....so that would explain the change. I have kept my chems in a drawer in A/C since I've had them. I have all new FC testing reagents so I'll be good for the slam.

    Thanks SO much!!
    25K GALLON IG VINYL
    LASER SAND JACUZZI FILTER #250L 66GPM JACUZZI 1.0 HP PUMP
    UNDER WATER LIGHT
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    Texas Splash's Avatar
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    Re: slam question

    You're welcome. Just to clarify one thing on the CYA ... it doesn't lower by evaporation. Instead, it remains in concentration and acclimates with the new water when added. That's why water exchange is the primary method of lowering CYA. But not to worry, with your good test kit you'll always be able to monitor it. Best to check CYA once a month or so just to make sure all is well. Let us know if you have any more questions when you get your stabilizer and start your SLAM. Enjoy the rest of your day.
    Pat (a.k.a. Texas Splash) ~ My Pool: Viking Fiberglass; 17,888 Gal; Waterway Supreme 2-sp/2-hp pump; Hayward Ctg filter; TF-100 w/ Speed Stir
    Vital Links: POOL SCHOOL, RECOMMENDED LEVELS, RECOMMENDED CHEMICALS, Poolmath Calculator, SLAM, Chlorine/CYA CHART.
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    Re: slam question

    Quote Originally Posted by Texas Splash View Post
    As a note, CYA (stabilizer) shouldn't have any effect on your pH.
    Pool Math would seem to disagree with this. It indicates it will lower the pH although the effect will be small especially will small amounts of CYA.
    11K gal IG screened-in plaster pool w/ spa
    pentair 150 cartridge filter, Pentair Intelliflow VS pump,
    Aquarite AQR15 SWG, AquaCal Heatwave Heat Pump, TF-100 test kit

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    elainerader's Avatar
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    Re: slam question

    Hello again......I have fixed the CYA level and adjusted the Ph:

    CYA 50
    Ph 7.2

    I'm in my 7th day of slam to get rid of the mustard algae.....UGH it's still there bright and alive although a lot less.
    I have been holding the FC level at 29.5 slam level as indicated on the chart for my CYA.
    Overnight it still looses about 3 ppm.
    I have been brushing once a day and running the pump 24/7.
    I have backwashed twice.
    Should this be a normal length of time to shock for a bad mustard algae attack? Should I consider adding diatomaceous earth to my sand? Or should I just continue as I am?

    Thanks
    25K GALLON IG VINYL
    LASER SAND JACUZZI FILTER #250L 66GPM JACUZZI 1.0 HP PUMP
    UNDER WATER LIGHT
    10 YEARS OLD, LINER 2 YRS OLD

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    Re: slam question

    Keep on trucking, doing what you're doing. There is no standard length of time that a SLAM will last, it all depends on the severity of the problem to start as well as how often you're brushing, testing and dosing. Dosing as frequently as possible to keep the FC at SLAM level will give the fastest results. Brushing frequently also helps. Be sure to remove ladders and lights and give them all a good scrubbing, including inside the light niche.

    DE can be added to help enhance filtration and I'd recommend trying it. Just be sure you're able to be around to monitor the filter pressure for several hours after adding DE to the sand filter. Start with a small amount, wait 30 minutes, check pressure, repeat until you get a 1 psi increase. Your filter size, I'd start with 1/4 cup mixed with pool water, dump into the skimmer, repeat as needed.
    Joel - TFP Moderator - Minnesota - **Become a TFP Supporter!** Helpful Links: ABCs of Pool Water Chemistry - SLAM Procedure - Chlorine/CYA Chart
    40x20 Pool: 32K Gallons * Vinyl * Bleach Chlorination * Hayward S270T Sand Filter * Pentair SuperFlo 1 HP * Teledyne/Laars Heater * AquaVac Tigershark * TF-100 w/ SpeedStir
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    elainerader's Avatar
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    Re: slam question

    Thank you for the re assurance!

    One more question. I have bee suspect of our light for quite some time....it's been holding some water for about a year and I can't get my husband to fix it
    I mentioned to him, that since we've always had a mild re-occuring mustard algae problem, that we should take out the light and clean (and fix it!) .....he felt there was no way algae could get in there....could this be the culprit?

    Also how do you take out the light without getting into the pool?? (dumb question) We don't own wet suits and the water is quite cold! (Even though we don't shut down the pool over the winter, its way too cold to swim)
    25K GALLON IG VINYL
    LASER SAND JACUZZI FILTER #250L 66GPM JACUZZI 1.0 HP PUMP
    UNDER WATER LIGHT
    10 YEARS OLD, LINER 2 YRS OLD

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    Mod Squad JVTrain's Avatar
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    Re: slam question

    Lights themselves that are leaking as well as the niche behind them can CERTAINLY be culprits for algae. When I first took over my pool after buying my house, the light was half full of water with algae inside. Also when I removed the light from the niche and brushed it out, a cloud of algae came out with it.

    Nearly all lights can be removed from the niche by removing a single screw on the top of the light. 12 o'clock on the light. Then it will tip outward from the top and you can lift the light out of the water, as long as when it was installed, they left plenty of cord behind the light. You can then clean the fixture, perhaps replacing the seal to fix the leak in the fixture and scrub out the niche where the fixture resides. A clean toilet brush is best for cleaning out the niche. I'm able to remove my light by laying on the pool deck and reaching into the water to get the screw out. Just don't drop the screw to the bottom!
    Joel - TFP Moderator - Minnesota - **Become a TFP Supporter!** Helpful Links: ABCs of Pool Water Chemistry - SLAM Procedure - Chlorine/CYA Chart
    40x20 Pool: 32K Gallons * Vinyl * Bleach Chlorination * Hayward S270T Sand Filter * Pentair SuperFlo 1 HP * Teledyne/Laars Heater * AquaVac Tigershark * TF-100 w/ SpeedStir
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  12. Back To Top    #12
    elainerader's Avatar
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    Re: slam question

    Thanks again for your tips, it appears there are screws around the entire ring but hopefully, as you say the 12:00 one might be the only one holding it on, hopefully
    25K GALLON IG VINYL
    LASER SAND JACUZZI FILTER #250L 66GPM JACUZZI 1.0 HP PUMP
    UNDER WATER LIGHT
    10 YEARS OLD, LINER 2 YRS OLD

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    Mod Squad JVTrain's Avatar
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    Re: slam question

    You can see from this image what you might be dealing with. This is a common Pentair or Amerilite style light that was common in the 90s for installation.

    There are screws all the way around to secure the housing to the front plate and tighten the rubber seal around the light, but at the top, there is a brass screw that holds the entire fixture in the niche. On the bottom of the light, there is a u-shaped tab that lines up with the bottom of the niche so only the tab and the top screw actually hold the light in place.
    Joel - TFP Moderator - Minnesota - **Become a TFP Supporter!** Helpful Links: ABCs of Pool Water Chemistry - SLAM Procedure - Chlorine/CYA Chart
    40x20 Pool: 32K Gallons * Vinyl * Bleach Chlorination * Hayward S270T Sand Filter * Pentair SuperFlo 1 HP * Teledyne/Laars Heater * AquaVac Tigershark * TF-100 w/ SpeedStir
    Isolated Spa - 345 Gallons

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    elainerader's Avatar
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    Re: slam question

    You are awesome! Thank you so much for going to the trouble of finding the photo and describing the whole process.

    I will get on this first thing tomorrow!

    25K GALLON IG VINYL
    LASER SAND JACUZZI FILTER #250L 66GPM JACUZZI 1.0 HP PUMP
    UNDER WATER LIGHT
    10 YEARS OLD, LINER 2 YRS OLD

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