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Thread: Questions about killing algae

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    Questions about killing algae

    I just read the sticky above on how to do this and have a few questions.

    By the way, I've ordered a TF-100 kit, and I expect delivery by this Monday, so I figured I'd wait until then to attack my algae. I've never used the methods of this forum before, but wanted to see if I could convert to your methods, as I'm getting the impression after reading your forum that your methods are more effective, more scientifically valid, and I think, cheaper as well (as cheaper is important to me... I always look for good deals.)

    I have a 7600 gallon round pool, so it's not really that big, but I'm seeing green, mainly towards the perimeter of the pool, but not so much in the middle.

    In the sticky, I see this statement: "The very first time through the cycle you can assume that the FC level starts at zero. After that you want to test the FC level and only add as much chlorine as needed to bring it back up to shock level."

    Why should should I assume I'm starting at zero? Shouldn't I use the test kit to see what my FC level is, and then use pool math to only add enough chlorine to that starting point to bring it to shock level?

    By the way, my pool came with an automatic chlorinator, which I've been using with 3 inch tabs to add chlorine, but I only bought one bucket of the tabs, and after reading here, I'm seriously thinking of not buying any more of those and switching to another chlorine source. I know a lot of you are fans of chlorine bleach, but I think that requires daily maintenance, and I was amazed to see that I can buy a SWG system for only $135, so I'm seriously considering buying that and installing it myself (to avoid the daily maintenance), as I see that the people in this forum consider that to also be an okay chlorine source, better than the 3 inch tabs in my bucket.

    Having said that, I read in the sticky that I'll still need something like chlorine bleach to kill the algae, because a SWG can't deliver the chlorine fast enough for slamming, plus I don't even have a SWG yet. This is okay to me... I'll go ahead and purchase chlorine bleach for the project of killing algae.

    Is this just the regular chlorine bleach that they sell in the grocery store for use in the laundry room, the type that you mix in white white clothing (not the bleach for colored clothing)?

    Also, I should mention that I've been testing my water with the test strips that came with my pool, but I've just used the last strip, which is one reason I ordered a test kit. I thought my chlorine has been normal, which is why the algae surprised me, but I should mention the simple strips just measured 3 things: chlorine, PH, and alkalinity.

    I don't completely understand the chemistry of chlorine, but doesn't free chlorine break down into something called chloramines? Could the chloramines be getting registered by my strips, giving me a false confidence in how much free chlorine I have? (There is just one chlorine reading on the strip.) Could this have contributed to the algae growth? I guess this will all get fixed when I get I get my TF-100 test kit.

    I also have a white plastic stair steps thing in my pool to make it easier to step down into it. It's actually hollow and filled with sand to weight it down, and it's screwed into my wooden deck. I'm kind of worried that it could be a source point for the algae. Do you think that during the algae treatment I'd like to start on Monday, that I should remove those steps and wash it down in case it has algae on it? I hope it's not too heavy to lift out of the pool. I wonder if I could replace the screws (there are 8 of them) with something (maybe bolts and nuts?) to make it easier to remove and reinstall in the future, in case this algae problem ever happens again.

    Also, unless I wait all the way until next weekend to start this algae treatment, that means to dedicate the 4 hours suggested by the sticky means at least some of it will be done in the dark. Is it okay to do this at nighttime, or do I need sunlight for any reason?

    Actually now that think of it, if I start Monday, that doesn't mean that's when I'll start shocking, as I see that if necessary, I could have to adjust PH and CYA before starting. I have no idea what my CYA level is, as I've never measured it. If I have to increase it, pool math says to add "stabilizer" Where could I find that, and is there any common household object that contains it (like bleach contains chlorine, for example). Or should I just go to a pool store and ask for stabilizer?

    I've actually owned pools at my two previous houses, but after reading this forum, I see that I never really had nearly the understanding of pool chemistry like the people in this forum do (and wound up spending a lot of money at pool stores treating the pools in ways that might not have been optimal). I'm glad I found this forum.
    18 foot diameter, 52" tall above ground Cornelius pool, with vinyl liner, and resin wall caps.
    Roughly 7600 gallons
    Blue Wave "Sandman" Sand filter/pump, model NE6150. Pump is 1 HP
    Intex SWG, model # 54601E

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    Re: Questions about killing algae

    Replies in red.
    Quote Originally Posted by Zindar View Post
    I just read the sticky above on how to do this and have a few questions.

    By the way, I've ordered a TF-100 kit, and I expect delivery by this Monday, so I figured I'd wait until then to attack my algae. I've never used the methods of this forum before, but wanted to see if I could convert to your methods, as I'm getting the impression after reading your forum that your methods are more effective, more scientifically valid, and I think, cheaper as well (as cheaper is important to me... I always look for good deals.)

    I have a 7600 gallon round pool, so it's not really that big, but I'm seeing green, mainly towards the perimeter of the pool, but not so much in the middle.

    In the sticky, I see this statement: "The very first time through the cycle you can assume that the FC level starts at zero. After that you want to test the FC level and only add as much chlorine as needed to bring it back up to shock level."

    Why should should I assume I'm starting at zero? Shouldn't I use the test kit to see what my FC level is, and then use pool math to only add enough chlorine to that starting point to bring it to shock level?

    By the way, my pool came with an automatic chlorinator, which I've been using with 3 inch tabs to add chlorine, but I only bought one bucket of the tabs, and after reading here, I'm seriously thinking of not buying any more of those and switching to another chlorine source. I know a lot of you are fans of chlorine bleach, but I think that requires daily maintenance, and I was amazed to see that I can buy a SWG system for only $135, so I'm seriously considering buying that and installing it myself (to avoid the daily maintenance), as I see that the people in this forum consider that to also be an okay chlorine source, better than the 3 inch tabs in my bucket.

    Having said that, I read in the sticky that I'll still need something like chlorine bleach to kill the algae, because a SWG can't deliver the chlorine fast enough for slamming, plus I don't even have a SWG yet. This is okay to me... I'll go ahead and purchase chlorine bleach for the project of killing algae.

    Is this just the regular chlorine bleach that they sell in the grocery store for use in the laundry room, the type that you mix in white white clothing (not the bleach for colored clothing)?
    Regular chlorine bleach. Not splashless, scented, outdoor bleach, and not colour-safe bleach.

    Also, I should mention that I've been testing my water with the test strips that came with my pool, but I've just used the last strip, which is one reason I ordered a test kit. I thought my chlorine has been normal, which is why the algae surprised me, but I should mention the simple strips just measured 3 things: chlorine, PH, and alkalinity.

    I don't completely understand the chemistry of chlorine, but doesn't free chlorine break down into something called chloramines? Could the chloramines be getting registered by my strips, giving me a false confidence in how much free chlorine I have? (There is just one chlorine reading on the strip.) Could this have contributed to the algae growth? I guess this will all get fixed when I get I get my TF-100 test kit.
    Yes, strips only report total chlorine levels and the reading isn't that accurate either.

    I also have a white plastic stair steps thing in my pool to make it easier to step down into it. It's actually hollow and filled with sand to weight it down, and it's screwed into my wooden deck. I'm kind of worried that it could be a source point for the algae. Do you think that during the algae treatment I'd like to start on Monday, that I should remove those steps and wash it down in case it has algae on it? I hope it's not too heavy to lift out of the pool. I wonder if I could replace the screws (there are 8 of them) with something (maybe bolts and nuts?) to make it easier to remove and reinstall in the future, in case this algae problem ever happens again.
    Yes, you should always remove steps when SLAMming as they are known to harbour algae. We recommend scrubbing removable steps with a mixture of 50% household bleach and 50% water. Also, if you follow the TFPC method, you should not have algae problems in the future.

    Also, unless I wait all the way until next weekend to start this algae treatment, that means to dedicate the 4 hours suggested by the sticky means at least some of it will be done in the dark. Is it okay to do this at nighttime, or do I need sunlight for any reason?
    It is actually better to do it at night as there will be no chlorine loss due to sunlight. That being said, the process should continue through the day as much as possible.

    Actually now that think of it, if I start Monday, that doesn't mean that's when I'll start shocking, as I see that if necessary, I could have to adjust PH and CYA before starting. I have no idea what my CYA level is, as I've never measured it. If I have to increase it, pool math says to add "stabilizer" Where could I find that, and is there any common household object that contains it (like bleach contains chlorine, for example). Or should I just go to a pool store and ask for stabilizer?
    There is no household object that contains CYA. CYA is sold as stabiliser/conditioner in the pool aisle of Walmart, Lowes, Home Depot or at the pool store. Look for 96%+ cyanuric acid/isocyanuric acid.

    I've actually owned pools at my two previous houses, but after reading this forum, I see that I never really had nearly the understanding of pool chemistry like the people in this forum do (and wound up spending a lot of money at pool stores treating the pools in ways that might not have been optimal). I'm glad I found this forum.
    See also instructions on SLAM, recommended pool chemicals and ABCs of pool water chemistry.

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    Re: Questions about killing algae

    Uh oh, I might feel silly after that long post... I actually haven't swam in about a week, and the pool looked green on the bottom to me, but I was looking in dim light. Now in the day, I'm not positive that what I'm looking at is green. There's a fair amount of residue on the bottom and I can't tell if it's stains (like algae would do), or if it's simply sand.

    I have another thread I started awhile back where I was noticing fairly tiny bits of what felt like under my toes as sand showing up in the middle of my pool, and I've been vacuuming it up. If what I'm seeing is sand, it's a lot more than was there before. I do have a sand filter, but it's only been one month since it and the pool was installed.

    This afternoon when I get time (as I have a lot of errands to go on right now), I should go in the pool and try to retrieve some of that residue and hopefully if I look at it in the light, close up, I'll be able to tell if it's sand. So I'm not 100% sure if I have algae or not at this point.

    Regardless, I do thank Abigail for her valuable information.

    - - - Updated - - -

    Wait... there's one more possibility. As I said, our plastic stair steps are filled with sand. For all I know, the steps themselves are leaking sand.
    18 foot diameter, 52" tall above ground Cornelius pool, with vinyl liner, and resin wall caps.
    Roughly 7600 gallons
    Blue Wave "Sandman" Sand filter/pump, model NE6150. Pump is 1 HP
    Intex SWG, model # 54601E

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    Re: Questions about killing algae

    Update: I don't think that residue is sand after all... It definitely has the slimy feel of algae. I'll be brushing the floor of the pool during the algae killing campaign.
    18 foot diameter, 52" tall above ground Cornelius pool, with vinyl liner, and resin wall caps.
    Roughly 7600 gallons
    Blue Wave "Sandman" Sand filter/pump, model NE6150. Pump is 1 HP
    Intex SWG, model # 54601E

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    Re: Questions about killing algae

    I have another thread I started awhile back
    Please don't add any more to that "other" thread. It is VERY confusing. Keep all future posts right here and do not atart ajnother threaed.

    Post up your numbers as soon as you get them.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    Re: Questions about killing algae

    Okay, but I should mention that in the other thread I was looking at just small bits of residue in the middle of the pool, which looks and feels like sand, but in this thread, I'm talking about the residue that exists near the perimeter (different residue, and much larger amounts of it), which as of yesterday I've confirmed is not the same residue (it's algae). If something comes up regarding the residue in the other thread (which I think was sand), it seems like to me that it would be confusing to put that into this thread.

    Back to the subject of this thread though, I've just purchased some bleach. In the spot where you usually would see the scent, it says "regular", so I assume that was correct of me to pick that one.

    In the ingredients, it says:

    Quote Originally Posted by label on bottle
    Active ingredient:
    Sodium Hypchlorite: 8.25%
    Other ingredients 91.75%
    Total 100%

    Yields 7.86% Available Chlorine.
    CONTAINS NO PHOSPHORUS
    A question I have: Should I assume it contains 8.25% chlorine in my calculations, or should I assume 7.86%?
    18 foot diameter, 52" tall above ground Cornelius pool, with vinyl liner, and resin wall caps.
    Roughly 7600 gallons
    Blue Wave "Sandman" Sand filter/pump, model NE6150. Pump is 1 HP
    Intex SWG, model # 54601E

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    Re: Questions about killing algae

    Yes, use 8.25 for your calculations. Regular is what you want. You don't have your location in your profile (so it shows up under your name) so I'm not sure where you are, but many areas of the country have higher concentrations of liquid chlorine available. Pool stores and some big box stores have 10% & 12.5%. Both of these would mean less toting of bottles during a SLAM.
    TFP Moderator 39 X 18 23,000(ish) freeform gunite; built 2007ish; Pentair Triton II TR100 600lb Sand filter; 2 HP Pentair pump with 2.2 HP AO Smith single speed motor; 2 skimmers, 1 main drain, 4 returns w/waterfall, Stenner 45MHP2 3GPD running@ 60% - 15 gal Tank; heated by the sun CYA 200+ when I started - 50 now. Dolphin Supreme M5 Pool Cleaner. Hot Springs SX Spa, 285 gallon

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    Re: Questions about killing algae

    Quote Originally Posted by tim5055 View Post
    You don't have your location in your profile (so it shows up under your name)
    Sorry; I just updated my profile (Austin, Texas).

    Anyway, I just received my TF-100 testing kit today (and optional borate testing strips). Reading the instructions and following them seemed quite time consuming, but hopefully I'll get used to it and faster with time.

    This is the first time I've tested this pool, by the way:

    FC 6
    CC 2
    PH 6.8
    TA 60
    CH 100
    CYA 70 <- I could barely see the black dot at 100, but I think I slightly passed the 70 mark before it completely dissappeared.

    Borates 30 ppm

    I included the borates measurement because I put in proteam supreme, and I followed the pool stores advice by adding muriatic acid to offset the PH raising effect of it. I haven't added proteam supreme or acid in weeks though.

    To me the PH looks too low now... so I wonder if I got bad advice from the pool store on how much acid to put in. If I need to raise the PH, one way is by adding more proteam supreme, because I have some. However, is 30 ppm already the correct amount of borates? If it is, maybe I should not add anymore proteam supreme.

    Anway, does it makes sense, given the above stats that I'd have algae in my pool? By the way, I should mention that I added some of my dichlor shock powder to the pool about 2 or 3 days ago, hoping it would help with the algae problem, so my above stats might be influenced by that.
    18 foot diameter, 52" tall above ground Cornelius pool, with vinyl liner, and resin wall caps.
    Roughly 7600 gallons
    Blue Wave "Sandman" Sand filter/pump, model NE6150. Pump is 1 HP
    Intex SWG, model # 54601E

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    Re: Questions about killing algae

    6.8 is the lower limit of the test, so you may be lower. Skip playing with the borates now and get teh pH in line first. Here is a clip from the Pool School (which you should be reading in your spare time )
    Raising PH

    PH can be raised in three ways: borax, soda ash, and aeration. Borax is usually the best choice. Borax raises the PH and also raises the TA level just a little. If your TA level is low soda ash will raise both the PH and TA levels. If your TA level is high, aeration is best as it will not raise the TA level at all. However, aeration is rather slow compared to the other two.

    Borax is available as 20 Mule TeamŪ Borax Natural Laundry Booster. It is sold in the laundry detergent section of most larger grocery stores and some big box stores. Borax is best added by pre-dissolving it in a bucket of water and then pouring that slowly in front of a return.

    Soda ash is available as ARM & HAMMERŪ Super Washing Soda Detergent Booster. Do not confuse this with ARM & HAMMERŪ laundry detergent! It is sold in the laundry detergent section of most larger grocery stores and some big box stores. It is also sold by pool stores under various names, including PH Increaser, PH Up, Balance Pak 200, etc. Soda ash is best added by pre-dissolving it in a bucket of water and then pouring that slowly in front of a return.

    Aeration can be provided by a SWG, spa jets, waterfall, fountain, return pointed up so it breaks the surface, air compressor, kids splashing, rain, etc. It can take some time for aeration to raise the PH. The higher your TA level, the faster aeration will work.
    CC=2 says something is growing in the water, so once you have the pH in line you need to read the directions on SLAMing your pool in the How To section of Pool School and follow that procedure completely to the end.
    TFP Moderator 39 X 18 23,000(ish) freeform gunite; built 2007ish; Pentair Triton II TR100 600lb Sand filter; 2 HP Pentair pump with 2.2 HP AO Smith single speed motor; 2 skimmers, 1 main drain, 4 returns w/waterfall, Stenner 45MHP2 3GPD running@ 60% - 15 gal Tank; heated by the sun CYA 200+ when I started - 50 now. Dolphin Supreme M5 Pool Cleaner. Hot Springs SX Spa, 285 gallon

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    Re: Questions about killing algae

    Are you borating the pool or are you just increasing pH? The MSDS indicates that proteam supreme is borax (sodium tetraborate pentahydrate), could you clarify your intentions?

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    Re: Questions about killing algae

    When I bought the pool (last June), the store that sold to me is for some reason really big on selling proteam supreme. He told me that it's supposed to reduce the need for other chemicals, so that was really the reason for adding it. I'm not sure if I've quite added as much as he told me to, and in the meantime I started reading this forum, so I figured maybe I could do my own testing (hence the borate strips I got) to see if I needed to add more or not.

    Since then, I read on this forum that proteam supreme is really optional, and a personal choice if I want it. I think I might have read that it might make the water feel more comfortable, which if so, sounds good, and since I already have the chemical, I figured I may as well use it.
    18 foot diameter, 52" tall above ground Cornelius pool, with vinyl liner, and resin wall caps.
    Roughly 7600 gallons
    Blue Wave "Sandman" Sand filter/pump, model NE6150. Pump is 1 HP
    Intex SWG, model # 54601E

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    Re: Questions about killing algae

    So, ph is the first thing to fix? Pool math is saying, if I'm reading it right, I should have 7.5 to 7.8, but isn't my CYA too high also? I think pool math says to the only way to lower that is by draining water, which seems like it would be a waste of chemicals to fix ph before fixing CYA. But my pool was freshly filled just last month. I don't see how my CYA could be too high. What could the source of that high reading be caused by? I'm hoping that I'm correctly using the TF-100 kit I got.

    I did have the water tested at a pool store in June, and it seems like my levels weren't that far off then, according to the guy that tested it.
    18 foot diameter, 52" tall above ground Cornelius pool, with vinyl liner, and resin wall caps.
    Roughly 7600 gallons
    Blue Wave "Sandman" Sand filter/pump, model NE6150. Pump is 1 HP
    Intex SWG, model # 54601E

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    Re: Questions about killing algae

    If you have been shocking / using pucks / dichlor / trichlor, then CYA 70 is entirely possible.

    With CC2 and seeing green, you really need to SLAM.
    It is recommended to do a partial drain and refill to lower your CYA, but it is also possible to SLAM at CYA 70 if you are under water restrictions.

    If you do go the drain/refill route, then you should do that before getting the pH in range. If you decide not to do a drain/refill then you need to be aware that you do not have much wiggle room on your CYA and will need to use bleach/liquid chorine to maintain your FC levels. See also how to chlorinate your pool.
    Whatever you decide, you need to adjust pH before beginning SLAM.

    We do not trust pool store testing, trust your readings from the TF-100.

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    Re: Questions about killing algae

    Also, I would recommend reading ABCs of pool water chemistry.

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    Re: Questions about killing algae

    Yes, I'll definitely do a slam once I get the other levels fixed.
    Quote Originally Posted by Abigail K View Post
    If you have been shocking / using pucks / dichlor / trichlor, then CYA 70 is entirely possible..
    I'm still surprised because I haven't used all that much of the dichloro shock, and less than a bucket of the chlorine tabs. I just thought it would have taken more than 1+ months of pool ownership for the CYA to migrate that high.
    18 foot diameter, 52" tall above ground Cornelius pool, with vinyl liner, and resin wall caps.
    Roughly 7600 gallons
    Blue Wave "Sandman" Sand filter/pump, model NE6150. Pump is 1 HP
    Intex SWG, model # 54601E

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    Re: Questions about killing algae

    Quote Originally Posted by Zindar View Post
    Yes, I'll definitely do a slam once I get the other levels fixed.
    I'm still surprised because I haven't used all that much of the dichloro shock, and less than a bucket of the chlorine tabs. I just thought it would have taken more than 1+ months of pool ownership for the CYA to migrate that high.
    Wasn't your earlier CYA reading from a pool store? I would not try to compare their reading with yours using your own kit. Pool stores (note the "s") that I went to all got my CYA wrong. They all told me it was less then 90 when it was really 200+

    When I bought the pool (last June), the store that sold to me is for some reason really big on selling proteam supreme.
    There is a large profit margin in these type of add on sales. The retail stores I worked at (another industry) paid flat commissions on regular sales (think a chlorine or acid purchase at a pool store) but you got a "Spif" for these add on sales. I guess that's why I always did lousy at retail sales, I can't look someone in the eye and lie to them.

    Trust your numbers and use Pool Math to figure out what you need to do.

    Like Abigail said, if you are going to drain/refill for the CYA do it first. If not, then get the pH in line and SLAM away.
    TFP Moderator 39 X 18 23,000(ish) freeform gunite; built 2007ish; Pentair Triton II TR100 600lb Sand filter; 2 HP Pentair pump with 2.2 HP AO Smith single speed motor; 2 skimmers, 1 main drain, 4 returns w/waterfall, Stenner 45MHP2 3GPD running@ 60% - 15 gal Tank; heated by the sun CYA 200+ when I started - 50 now. Dolphin Supreme M5 Pool Cleaner. Hot Springs SX Spa, 285 gallon

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    Re: Questions about killing algae

    Quote Originally Posted by Zindar View Post
    I'm still surprised because I haven't used all that much of the dichloro shock, and less than a bucket of the chlorine tabs. I just thought it would have taken more than 1+ months of pool ownership for the CYA to migrate that high.
    It doesn't take a lot of dichlor and tabs to move the CYA. In your pool 16oz of dichlor will raise your CYA 8.9 and a tab (I think they are 8oz) will raise your CYA 4.9. Numbers move fast in a smaller pool.
    TFP Moderator 39 X 18 23,000(ish) freeform gunite; built 2007ish; Pentair Triton II TR100 600lb Sand filter; 2 HP Pentair pump with 2.2 HP AO Smith single speed motor; 2 skimmers, 1 main drain, 4 returns w/waterfall, Stenner 45MHP2 3GPD running@ 60% - 15 gal Tank; heated by the sun CYA 200+ when I started - 50 now. Dolphin Supreme M5 Pool Cleaner. Hot Springs SX Spa, 285 gallon

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    Re: Questions about killing algae

    Quote Originally Posted by tim5055 View Post
    Wasn't your earlier CYA reading from a pool store?
    Yes, but it was also a freshly filled pool, using City of Austin municipal water. (By the way, I had to truck in that water, as I live outside the city limits, and we have pool filling water restrictions where I live.) Admittedly I have no idea how much CYA is naturally occurring in municipal water.

    Quote Originally Posted by tim5055 View Post
    It doesn't take a lot of dichlor and tabs to move the CYA. In your pool 16oz of dichlor will raise your CYA 8.9 and a tab (I think they are 8oz) will raise your CYA 4.9. Numbers move fast in a smaller pool.
    Okay, that explains a lot; thank you.

    By the way, I owned my last two pools for years each, and I had (for years) used dichlor shock and, in the case of one of those pools, chlorine tabs as well, and I don't remember having CYA problems, but on the other hand, maybe I never tested for CYA (i.e. maybe the pool store never tested for it). Actually I know they did test for it in the case of my SW pool, because I remember adding stabilizer on their advice. I can't remember if if was tested for the chlorine tab pool.

    Anyway, thanks for this education that in my small pool, the CYA can get out of hand fast. I think I'd like to give a try using the existing water to save on my water bill. Maybe eventually between backwashing and water splashing, the CYA will eventually come down on its own. Also, who knows; it was my first crack at the TF-100, and I don't know how accurately I measured things.

    So this morning, I used materials I had on hand to try to raise the PH. I reasoned that since my borates are at 30 ppm, and I hear that its okay to go up to 50 ppm, and since I still have some proteam supreme on hand, this morning I added some. The pool store told me not to add more than 2 cups in the morning, and not more than 2 cups in the evening, so I added 2 cups this morning, and when I get home this evening, I'll see how much impact that had on the PH, and I'll continue treating the the PH until it's in range, before I starting thinking about slamming. I guess if the borates reach 50ppm and my PH is still too low, I'll have to switch PH treatment strategies. I do have the chlorine bleach on hand, so I'm ready to slam, when my pool is. I just hope it won't be too hard to lift the stairs out of the pool. With the stairs out, maybe I can brush the algae by using a brush on the end of my pool pole.

    By the way, we recently had several inches of heavy rain, and I'm thinking it's possible that's why my PH is low. The water was also above the top of my skimmer because of it, but yesterday I backwashed (and I could tell the filter needed backwashing, judging from how dirty the backwashed water was), and now the water is a just a bit below the top of the skimmer, which is probably good because when it goes above the top of the skimmer, I have a feeling that interferes with the skimmer's ability to skim. Also, on the advice of this forum, I noted the filter pressure after I backwashed, so that I have a benchmark to compare to, to have a good idea when it's time to backwash again.

    Quote Originally Posted by Abigail K View Post
    Also, I would recommend reading ABCs of pool water chemistry.
    That's a great link; thanks for that. I'm still reading it, but haven't finished it. I did already read the link about slamming a few days ago, but this ABC link does seem like essential reading.
    18 foot diameter, 52" tall above ground Cornelius pool, with vinyl liner, and resin wall caps.
    Roughly 7600 gallons
    Blue Wave "Sandman" Sand filter/pump, model NE6150. Pump is 1 HP
    Intex SWG, model # 54601E

  19. Back To Top    #19
    Mod Squad tim5055's Avatar
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    Re: Questions about killing algae

    Municipal water will have "0.0" CYA. There is no need for them to add this to the water supply.

    You certainly can maintain a pool with CYA 70, heck mine is 80 and sparkling clear. You just have to maintain a higher FC level due to the additional CYA. Where the problem will come in is when (sorry to say I still think you will have to) you SLAM you will need to have a higher level of FC, which means more chlorine than if you had a lower CYA level.

    You are already way ahead of many folks because you have your test kit and are reading the Pool School and asking questions. That is what this site is all about - empowering you to take control of your pool.

    Remember, with CYA 70 the minimum your FC should ever be is 5 with a target of 8. I would say get it to 8 before you go to work and see what it is when you com home each day. You will get a feel for the appetite of your pool for chlorine. If the usage continues to be high it is just another sign that the SLAM is needed.
    TFP Moderator 39 X 18 23,000(ish) freeform gunite; built 2007ish; Pentair Triton II TR100 600lb Sand filter; 2 HP Pentair pump with 2.2 HP AO Smith single speed motor; 2 skimmers, 1 main drain, 4 returns w/waterfall, Stenner 45MHP2 3GPD running@ 60% - 15 gal Tank; heated by the sun CYA 200+ when I started - 50 now. Dolphin Supreme M5 Pool Cleaner. Hot Springs SX Spa, 285 gallon

  20. Back To Top    #20

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    Jun 2011
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    Re: Questions about killing algae

    Just to verify, the ABC's link says ph should between 7.5 and 7.8. So that's regardless of the type of pool? So could I start slamming as soon as it gets up to 7.5? The good news is that this morning's treatment apparently raised it from 6.8 to 7.2, over half the distance needed. I'm thinking of putting the same amount of proteam supreme again right now, which will hopefully get it within range, but first I'm going to do a borates test to make sure I'm not up the 50 ppm, lest I get too much borates into the pool. I'm also tempted (even though it's just one day since my last test) to do another CYA test to give me confidence that my reading was accurate.

    Edit: I just did the borates test, and the color's a little patchy and not the easiest to read, but my best guess is that it's up to 40 ppm. So I guess I could do one more application, but it's probably pushing it.

    Edit2: More good news. This time when I measured the CYA I got a little less than 60. Maybe it's because today I did it outside with sunlight, so it's easier to see the black dot through the solution. I will say that at the 70 calibration mark, I could just barely see the black dot, and it was fuzzy, but if I stared, I could certainly see that region was darker than the perimeter (though I could just make that out), and only when it went a tad over the 60 mark could I say I just couldn't see it at all. I also had enough of the solution left over, that about 10 minutes later I used it to do another reading. By then the sun had just dipped below the neighbor's roof, so less direct light, but I still got the same reading: A tad lower than 60. So maybe this will give me a bit of a break on the chlorine requirements vs what I thought I'd be dealing with.

    Meanwhile I guess I have to give time for the pump to run and mix up the ph rising chemical, so I guess I can't really slam until tomorrow, I assume.
    18 foot diameter, 52" tall above ground Cornelius pool, with vinyl liner, and resin wall caps.
    Roughly 7600 gallons
    Blue Wave "Sandman" Sand filter/pump, model NE6150. Pump is 1 HP
    Intex SWG, model # 54601E

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