Become a TFP Supporter Pool Math Forum Rules Pool School
Page 1 of 2 12 LastLast
Results 1 to 20 of 28

Thread: Green Algae's behavior at target FC and SLAM?

  1. Back To Top    #1

    Join Date
    Jul 2014
    Location
    NJ
    Posts
    123

    Green Algae's behavior at target FC and SLAM?

    I'm curious. If you had green algae in the past but don't see any sign of it and are at target FC levels, how does algae grow back?

    Even more curious, I realize the SLAM procedure is to kill off any algae in the pool, but if you are at target FC levels, won't that slowly kill the algae off anyway? (or is it that the algae grows faster than the FC particles can kill it)
    20x40 L-shape 35k gallons, Pentair FNS 60 SQFT DE Filter, Pentair Multi-port Valve, Hayward Super Pump w/1 glorious HP, Vinyl Liner, Dolphin Z5, TF-100 w/Speed Stir

  2. Back To Top    #2
    Texas Splash's Avatar
    Join Date
    Jun 2014
    Location
    South-Central Texas, Marion/San Antonio
    Posts
    12,955

    Re: Green Algae's behavior at target FC and SLAM?

    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.
    If you enjoyed your TFP experience, please consider donating to Support TFP!

  3. Back To Top    #3
    Divin Dave's Avatar
    Join Date
    Oct 2013
    Location
    Longview, Texas
    Posts
    4,926

    Re: Green Algae's behavior at target FC and SLAM?

    You pretty much got it.

    If you have any algae, it can multiply faster than the FC can kill it. Of course depending on how much there is.
    As the algae is killed off, FC drops, and before you know it, the FC is below the effective threshold of being buffered by CYA.
    So if algae is present, you only need to loose a couple ppm of FC before its ineffective in fighting off the algae.
    Divin Dave,
    IG Vinyl, 15' x 30', 3 1/2' - 6' deep, Oval, ~15K gal, Intelliclor IC40, Intelliflo VS pump, Clean and Clear 420 Filter, auto-fill-disabled, Retrofit LED Color Light, Dolphin Nautilus Robot, TF100 Test Kit, Taylor K1766 Salt Test Kit, Tftestkit Pressure Gauge.
    www.tftestkits.net Experience- it's what's learned just after you needed it most !!

  4. Back To Top    #4
    Texas Splash's Avatar
    Join Date
    Jun 2014
    Location
    South-Central Texas, Marion/San Antonio
    Posts
    12,955

    Re: Green Algae's behavior at target FC and SLAM?

    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.
    If you enjoyed your TFP experience, please consider donating to Support TFP!

  5. Back To Top    #5
    Richard320's Avatar
    Join Date
    Jan 2010
    Location
    San Dimas, CA (LA County)
    Posts
    18,768

    Re: Green Algae's behavior at target FC and SLAM?

    Quote Originally Posted by pisymbol View Post
    I'm curious. If you had green algae in the past but don't see any sign of it and are at target FC levels, how does algae grow back?

    Even more curious, I realize the SLAM procedure is to kill off any algae in the pool, but if you are at target FC levels, won't that slowly kill the algae off anyway? (or is it that the algae grows faster than the FC particles can kill it)
    In the case you're presenting, even though the army of algae has been defeated with a SLAM, a few tough diehards stayed behind to wage a guerilla war. They hide in places that are hard to brush and where there is poor water circulation. Algae grows a slimy biofilm that protects it from chlorine, which is why brushing is necessary. If you can't brush it, it can grow behind the shield.

    Algae spores are everywhere. How else do you explain some old empty can in the yard full of rainwater turning green? The battle in the pool is just low intensity most of the time.
    16K freeform gunite with spa; Pentair 4000 DE filter; Century Whisperflow 1 HP; Pentair Minimax heater.
    Troublefree does not mean Maintenancefree. It's like brushing your teeth: You can spend a couple minutes a day and pennies a week or go to the dentist once a year and spend several thousand dollars.
    A pool is like a pet - you have to feed it every day, even the days you don't want to play with it!

  6. Back To Top    #6

    Join Date
    Jul 2014
    Location
    NJ
    Posts
    123

    Re: Green Algae's behavior at target FC and SLAM?

    Quote Originally Posted by Texas Splash View Post
    Thanks for this, that was very informative.
    20x40 L-shape 35k gallons, Pentair FNS 60 SQFT DE Filter, Pentair Multi-port Valve, Hayward Super Pump w/1 glorious HP, Vinyl Liner, Dolphin Z5, TF-100 w/Speed Stir

  7. Back To Top    #7

    Join Date
    Jul 2014
    Location
    NJ
    Posts
    123

    Is this true? When FC drops but CC doesn't rise...

    ...the FC was removed from the pool due to sunlight and/or evaporation not from killing algae or other organics.

    Is this always true? I ask because I have gone two days straight passing the ONCT but now on my third I see that my FC dropped 1.5 ppm but I have had 0 CC since passing my first ONCT (I mean zero zero...). Also note, no signs of anything in the pool (it as clean as it can possibly be, water is almost invisible!).
    20x40 L-shape 35k gallons, Pentair FNS 60 SQFT DE Filter, Pentair Multi-port Valve, Hayward Super Pump w/1 glorious HP, Vinyl Liner, Dolphin Z5, TF-100 w/Speed Stir

  8. Back To Top    #8
    Texas Splash's Avatar
    Join Date
    Jun 2014
    Location
    South-Central Texas, Marion/San Antonio
    Posts
    12,955

    Re: Is this true? When FC drops but CC doesn't rise...

    Good to hear your water is clear. Yes, your FC will drop naturally each day based on the amount of sunlight it gets and organic matter it has battled against. Having a CC level of zero is good (ideal in fact) and just means that your water is in a very good place right now. We all lose FC each day differently, so over time we learn how much we expect to replenish each day. Does that help you?
    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.
    If you enjoyed your TFP experience, please consider donating to Support TFP!

  9. Back To Top    #9

    TFP Guide

    AimeeH's Avatar
    Join Date
    Apr 2012
    Location
    Columbia SC
    Posts
    1,837

    Re: Is this true? When FC drops but CC doesn't rise...

    If you didn't pass the OCLT, you still have something organic causing your chlorine to be consumed. I would proceed to SLAM chlorine level and repeat OCLT.

    I had clear water when a small patch of algea appeared on the floor. 4 days into the slam I STILL didn't pass OCLT with clearly sparkly water. Daughter swimming underwater identified for me where she saw "grime" in the tiny cracks in the framing around the shallow steps and deep end swim out. These are cracks where the two frames meet, not flaws. It took getting a hand brush in the pool and sure enough algea was hiding there as well as behind the skimmer box frames. Places my pool brush would never reach.

    So, I'd say if you lost 1.5 overnight, you still have something hiding.

    That is if I understood your question. Losing 1.5 during daylight would be normal. But bad overnight.
    18*36*23 true "L" vinyl IG 29,000 gallons. SWG. TF-100 test kit.
    http://tftestkits.net/splash-page.html

  10. Back To Top    #10

    Join Date
    Jul 2014
    Location
    NJ
    Posts
    123

    Re: Is this true? When FC drops but CC doesn't rise...

    Ok, it's just that I have no where else to look.
    20x40 L-shape 35k gallons, Pentair FNS 60 SQFT DE Filter, Pentair Multi-port Valve, Hayward Super Pump w/1 glorious HP, Vinyl Liner, Dolphin Z5, TF-100 w/Speed Stir

  11. Back To Top    #11
    Propbndr's Avatar
    Join Date
    Mar 2015
    Location
    Charles City, Va
    Posts
    232

    Re: Green Algae's behavior at target FC and SLAM?

    The nooks and crannies in the underside of pool ladders is another favorite place for algae to hide. Normally, these places get little or no circulation (even if you have a return jet pointed directly at the ladder) because of their location. The only real way to clean them out is to scrub them with a small brush then submerge the entire ladder, on its side, in the pool during the SLAM process. Or you could turn it upside down and lean against your fence and pour bleach into them. I did the latter and no longer have algae trying to get a foothold anywhere.
    Steve
    32 X 16 inground, 17260 gallons, Vinyl Liner, Triton II TR-60 filter,
    Sta-Rite 1hp pump Model #MPRA6E-147L, CircuPool SI-30 Plus SWG, TF-100 Test Kit

  12. Back To Top    #12
    Texas Splash's Avatar
    Join Date
    Jun 2014
    Location
    South-Central Texas, Marion/San Antonio
    Posts
    12,955

    Re: Green Algae's behavior at target FC and SLAM?

    pisymbol, something else to consider since I've been thinking about your situation quite a bit from your last post earlier today .... I first read your question in general terms of FC loss during the day, but I see now it appears you are curious about the 1.5 loss overnight, is that correct? After passing 2 days in a row, only to discover a "close" excess loss the 3rd night, it certainly is possible something is trying to return. Good thing is that if your test numbers have been rock-solid for a while, and you do SLAM, it shouldn't take too long to kill any algae. Since you have one of the best kits on the market (TF-100), and I'm assuming you are comfortable using it by now, user error is probably ruled out.

    If you would like, along with the advice of the past few comments today, you are certainly welcome to post a full set of numbers for us later this evening. Maybe it will give you some validation before this evening in case you decide to do another OCLT. Just a thought.
    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.
    If you enjoyed your TFP experience, please consider donating to Support TFP!

  13. Back To Top    #13

    Join Date
    Jul 2014
    Location
    NJ
    Posts
    123

    Re: Green Algae's behavior at target FC and SLAM?

    So Texas Splash, since I have a lot of faith in you guys I decided to do the following:

    1) Let the FC fall back to normal swim levels (you'll see why in a moment)
    2) Enter the pool and do a full interior inspection (something I can't do while in SLAM mode)
    3) I noticed deep inside the skimmers, all the way in the corner, there is live green algae (you have no idea how obscure this spot is and it's ONLY because I am a big believer in the TFP methodolgy that I went this far).
    4) I cleaned that algae off
    5) Continued the inspection and found nothing (in the process I wiped down the entire side walls of the entire pool THREE times)
    6) The ladder has been out of the pool, cleaned off and dry for days now (I don't want to introduce any more variables, it's the engineer in me)

    I have a humongo party on the 20th (family, friends, the whole nine).

    I am going to try to test tonight and see what my overnight chlorine loss is. The quandry I have now is if I start a SLAM tomorrow, I will have to go full stop on Wednesday since I want to the FC to be about 8-10.

    My last numbers this morning were:

    FC 9 (0 CC and I mean zero)
    CYA 45-50
    PH 7.2

    I brought it up to FC 12 when I cleaned out the algae. I realize I'm not in shock mode but I suppose there is a slim chance that at these FC levels I might pass an ONCT? Right?
    20x40 L-shape 35k gallons, Pentair FNS 60 SQFT DE Filter, Pentair Multi-port Valve, Hayward Super Pump w/1 glorious HP, Vinyl Liner, Dolphin Z5, TF-100 w/Speed Stir

  14. Back To Top    #14
    Mod Squad pooldv's Avatar
    Join Date
    Aug 2012
    Location
    DFW, TX
    Posts
    23,994

    Re: Green Algae's behavior at target FC and SLAM?

    Sure, it is worth a try. Do you have a light? That seems to be a favorite hiding place.
    TFP Moderator
    If TFP helped you or saved you money - Become a TFP Supporter! <--Click here
    2012 build and pics, 20k gal gunite, black onyx pebblesheen, OK flagstone, IntellifoVS, cart filter w/Pleatco, IC40 SWG, Solartouch, 5 12'x4' solar panels, HP50HA heat pump, 8mil solar cover, borates, TF-100 test kit, SONOS, Doheny's Discovery Robot, hot tub on bleach

  15. Back To Top    #15

    Join Date
    Jul 2014
    Location
    NJ
    Posts
    123

    Re: Green Algae's behavior at target FC and SLAM?

    I just got back from an event with the wife.

    12:15AM EST
    FC/CC 10.5/0.5

    (I did not test CYA, it is too dark, but I will assume my afternoon 45-50 reading is good enough).

    The filter will run all night. Pool *looks* clean as a whistle but I brushed a few areas where I have seen sporadic dead algae before for S&G's.

    I DO have a pool light but it is enclosed and I have brushed everything on top of it and around it. What else do I need to do? (I have never even thought about removing the top cover to the pool light).

    I got to tell ya, no one I know goes through what I'm gong through and I am beginning to think most people just live with algae to some extent (pool folks just clean it off or dump more chemicals to abate the issue temporarily).
    20x40 L-shape 35k gallons, Pentair FNS 60 SQFT DE Filter, Pentair Multi-port Valve, Hayward Super Pump w/1 glorious HP, Vinyl Liner, Dolphin Z5, TF-100 w/Speed Stir

  16. Back To Top    #16

    Join Date
    Jul 2014
    Location
    NJ
    Posts
    123

    Re: Green Algae's behavior at target FC and SLAM?

    I'm about to scream....so last night I must have been tired because after testing twice this morning I have:

    6:15AM EST:
    FC 12.5 / CC 0.5
    CYA 45-50
    pH 7.5

    +2FC which makes no sense to me.

    What I don't understand is I added sod-hypo before I left last night around 6:30PM. I had the filter on non-stop and took reading a little past midnight as per comment #15. I would think that would be more than enough time for the chlorine to mix to get an accurate reading. Right? I guess wrong since I'm +2 FC. And yes, I know how to test with the TF-100 (it's not exactly hard). CYA is the same so that's not it. Argh.

    I just added some acid to bring it back down to 7.2 (usually takes about a half hour).

    Well, the algae is back and with a vengeance, I see it growing out of the lines now and I have now not a clue how this can be possible. Perhaps someone is coming late in the night and dumping highly active green algae spores in my pool. Or maybe it's ancient alients screwing (it's a family website) with me.

    One thing, I can not SLAM all friggin summer, both due to the cost and the fact people want to swim in it. I'm at a loss now on what to do.

    I am going to bring the pool up to shock, scrub the whole pool down and then figure what to do for the 20th. No one has this problem but me and everyone I talk to that has had some algae goes to the pool store and buys algeacide which is what I don't want to do. What I don't understand is how fast it comes back compared to other folks stories. What the heck am I dong wrong?
    20x40 L-shape 35k gallons, Pentair FNS 60 SQFT DE Filter, Pentair Multi-port Valve, Hayward Super Pump w/1 glorious HP, Vinyl Liner, Dolphin Z5, TF-100 w/Speed Stir

  17. Back To Top    #17
    Propbndr's Avatar
    Join Date
    Mar 2015
    Location
    Charles City, Va
    Posts
    232

    Re: Green Algae's behavior at target FC and SLAM?

    Did you draw your sample from the same location as all your previous samples? If not, you may have a zone that is not seeing the same circulation as other parts of your pool.

    Also during the test, you could have miss counted the reagent drops or, a couple of drops came out at the same time and you did not see all of them. It has happened to me, especially for the first couple of drops, if the reagent is warm. I now give all open reagent bottles a quick squeeze before I start any test to equalize them.

    BTW, it is not necessary to test the CYA levels each time you test FC. You're just wasting your reagent. It is not going to change unless you change the water or get a lot of rain.
    Steve
    32 X 16 inground, 17260 gallons, Vinyl Liner, Triton II TR-60 filter,
    Sta-Rite 1hp pump Model #MPRA6E-147L, CircuPool SI-30 Plus SWG, TF-100 Test Kit

  18. Back To Top    #18

    Join Date
    Jul 2014
    Location
    NJ
    Posts
    123

    Re: Green Algae's behavior at target FC and SLAM?

    Quote Originally Posted by Propbndr View Post
    Did you draw your sample from the same location as all your previous samples? If not, you may have a zone that is not seeing the same circulation as other parts of your pool.
    Same location.

    Also during the test, you could have miss counted the reagent drops or, a couple of drops came out at the same time and you did not see all of them. It has happened to me, especially for the first couple of drops, if the reagent is warm. I now give all open reagent bottles a quick squeeze before I start any test to equalize them.
    Good idea, will do.

    BTW, it is not necessary to test the CYA levels each time you test FC. You're just wasting your reagent. It is not going to change unless you change the water or get a lot of rain.
    Yes, I know that. But the sudden increase of FC confuzzled me so I wanted to go back to a steady state.
    20x40 L-shape 35k gallons, Pentair FNS 60 SQFT DE Filter, Pentair Multi-port Valve, Hayward Super Pump w/1 glorious HP, Vinyl Liner, Dolphin Z5, TF-100 w/Speed Stir

  19. Back To Top    #19

    Join Date
    Jul 2014
    Location
    NJ
    Posts
    123

    Re: Green Algae's behavior at target FC and SLAM?

    And here is what I see (see the lines, there is something growing out of them).
    20x40 L-shape 35k gallons, Pentair FNS 60 SQFT DE Filter, Pentair Multi-port Valve, Hayward Super Pump w/1 glorious HP, Vinyl Liner, Dolphin Z5, TF-100 w/Speed Stir

  20. Back To Top    #20
    Defgufman's Avatar
    Join Date
    Mar 2015
    Location
    Savannah GA
    Posts
    577

    Re: Green Algae's behavior at target FC and SLAM?

    Yep that stuff is hiding in there waiting for fc to drop so it can start again.
    Inground 13,200 gal Vinyl, Pentair 3/4 hp pump, Pentair Sand Dollar filter, Polaris 280

    Pool School, Pool Math, CYA to FC ratio chart, Testing Kits

Page 1 of 2 12 LastLast

Posting Permissions

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