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Thread: 50+ppm FC and Pool Still Green??

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    50+ppm FC and Pool Still Green??

    OK, new member here. I've been reading this forum (and just about everything else I can google) on treating algae. I've been dumping massive amounts of chlorine into my pool-swamp, and have seen a little improvement but not as much as I had hoped. FWIW, the algae seems to be just floating in the water, not clinging to the walls, or on the steps, so I hope that's a good sign.

    Here are my numbers:

    Pool type: White plaster
    Size: appx 23,500 gallon
    Filter: Sand (new Zeobest 8/1/08)
    Cleaner: Barracuda G3
    Pump: 1.5 HP StaRite
    Run time (for now): 24/7

    Baseline chem (before treatment):

    FC=0
    PH=7.8
    TA=120
    CH=550
    CYA=135-150
    TDS=???

    I have a basic test kit (Taylor DPD, PH, TA), and also 5 way strips (PH, TC, FC, CH, TA, CYA). I know strips aren't the best, I just use them to verify my other numbers to see if they're in the same ballpark. I'm going to order a Taylor K-2006 on Monday, so I can get all my own numbers. Right now I have to rely on the pool store to tell me CH and CYA, much as I hate that. I *think* the CYA and CH numbers are close because they came from the PS and my test strip results are pretty much in line with them.

    Anyway, the back story is that I've been fighting algae almost all summer, ever since the water temp got above 80 degrees, which was back in early June (we're in Phoenix, AZ). I'd been using trichlor tabs in the floater, and powdered trichlor for shocking. I never gave a thought to the CYA I was adding to the pool and wasn't testing for it myself because my test kit didn't cover it and I hate going to pool stores. I liked the trichlor powder and pucks because it kept the pH in line and always seemed to do the trick against the algae.

    Of course, I got to the point that I couldn't get rid of the algae no matter what I did. So, I finally relented and went to the pool store to have them test my water and maybe give me some advice. When I did, of course, the number that jumped out was the CYA, which was close to 300!! Well, of course that means drain, but since it's summer, there's no way to drain a white plaster pool until the ambient temps are in the 60's or so, which won't be until November. I did a partial water swap (23,000 gallons and a $70 water bill later) by using a small pump and the garden hose. and got the CYA into the range I have now. That's when I started doing some research and found out about all the problems that CYA causes with pool chemistry, and I know that even after I do the drain I'll probably have enough residual CYA leaching out of the plaster that I won't have to add any (or very little) for some time.

    After I did the water swap and got the CYA down a bit, I was able to shock with about 6 or 7 lbs. of cal hypo and that got the water back to cloudy blue. That's also when I decided to change the sand (5 yrs old) to zeobest, in hopes of clearing the water even faster. Even after doing that, and with running the filter 24/7 for a week, it never did clear up. So, I just kind of gave up for a while and let the pool go back to green, thinking I'd just let it stay that way until November when I could do a complete drain and refill. I was letting the filter run about 10 hours a day just to keep the water moving and filtered for floating stuff.

    But after a few weeks, I couldn't stand the sight of "the swamp" anymore. So I did some research and found out lots of info on TFP and elsewhere, that basically said if you add enough chlorine it will eventually kill the algae. I found the "Pool Calculator" online, and Chemgeek's "Chlorine/CYA chart", so I have an idea of what I think I'm up against in terms of keeping the FC high enough above the CYA. Even if I don't get all the way to sparking, I'm OK with cloudy blue for now (we're done with swim season anyway) until I can drain. I just don't want to look out my window anymore and see a swamp.

    So, I bought some 70% cal hypo 1 lb bags, and then also found a pool store that sells 4 1-gallon jugs of 12.5% liquid for $11 so I bought 5 cases (20 gallons) of that as well. Last night, before sundown, I adjusted my pH down to about 7.2, added 6 bags of the cal hypo, and after about 30 minutes, put in 3 bottles of the liquid. Checked the pool about an hour later (it was dark) but it looked like the green was gone but just cloudy.

    This morning, the water was a cloudy light green, much better but still not blue or gray. I checked the pH, which was back to around 7.8, and the FC (using the dilution method, I had to go 20:1 to be able to read it on my DPD kit) which was at about 30. So I added about a quart of acid, and 2 more gallons of liquid chlor, and within about 30 minutes, the darker green cast came back. So I added 4 more gallons of liquid in hopes of getting some results, and had to leave for work.

    Came home, no difference in the pool, still dark green. Checked the FC again using the dilution method, was still at 35-40. Added another 4 gallons of liquid. So in the last 24 hours, I've added enough **unstabilized** (won't make the CYA mistake again) chlorine to put about 70ppm chlorine the pool. That seems like that should have been more than enough to kill anything that was there, even if some of it was used up in the process.

    I haven't tested for nitrates or metals. Since I can't see the bottom, there might be a fair amount of organic material down there (the cleaner has been out for quite a while since I've been superchlorinating), but is there anything else I'm missing?? Or do I just need more patience (and chlorine)?

    Thanks for any help or suggestions!!!

  2. Back To Top    #2

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    Re: 50+ppm FC and Pool Still Green??

    Welcome to the forum. You have a common issue and the folks on this forum can solve it for you.....but you may not like the cure.......you'll have to give up some of the "convenience" items.

    1. Your CYA is still w-a-a-a-y too high. You are beating your head against the wall trying to keep that pool clear when the CYA has essentially rendered your chlorine ineffective.

    You really need to get your CYA into the 40-60 range. That may require that you drain 1/3 of your pool and then drain 1/3 again and possibly even again but, until you get your CYA down to a manageable level, you will continue the same frustrations you currently have.

    2. Stop using Cal Hypo. Your CH is already too high and you are only driving it higher. Continued use will cause you some secondary problems that can/will cloud your water.

    3. Stop using Tri chlor. That's what has driven your CYA to it's present level and it's continued use will only exacerbate the problem

    All other methods to clear your pool are just chipping around the edges.......once you commit to getting your CYA into the 40-60 range, you will have a very easy time balancing the rest of your chemistry and can get back to enjoying your pool.
    Dave S. - Forum owner
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

  3. Back To Top    #3
    Butterfly's Avatar
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    Re: 50+ppm FC and Pool Still Green??

    Hi Kuladog and welcome to the forum!

    As usual, duraleigh has given excellent advice!

    Do you think another $70-water-bill-partial-swap-of-water might be the better financial choice? ...in the long run?

    Many folks in your part of the country run a higher CYA, like 70 to 90, especially if the pool is getting full sun......but, every pool is different!

    Some of your AZ neighbors will probably chime in soon and you'll get some 'local' advice!

    Glad to hear you are going to order a good test kit, the Taylor K-2006, but I also point out the kit comparision chart found in Pool School.....category/pool-school/pool_test_kit_comparison

    You will find that you get more for your money with TF Test Kits. I highly recommend the TF Test kit sold by duraleigh (Dave), a very active member on this site. He also has excellent customer service and will ship same day if the order is received before 2 p.m.....I think I'm correct on that same day shipping info, but I KNOW I'm correct about the customer service .

    You can find a link to TFTestKits.com in my sig and on the home page. Oh, duraleigh gives a $10 discount to TFP Supporters! :P

    When you have a few minutes, please add all your pool and equipment info in your signature. Also, adding your location in your profile will be a big help!

    Lots of members here to help you clear your pool and keep it that way!

    So, do you have a pic of the pool to share? green or blue or any color, we don't care We love pix!
    TFP Moderator TF100 Test Kit TF100 TestKit YouTube Channel PoolMath
    You're done SLAMing when:
    1)You lose 1ppm or less FC overnight, & 2)You have .5ppm CC's or less, & 3)your water is clear.

    ~ One should not use a sledge hammer to swat a mosquito. ~

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  4. Back To Top    #4

    Re: 50+ppm FC and Pool Still Green??

    Thanks for the speedy replies, duraleigh and butterfly. I will try to get a pic later on today to post.The good news is that I just needed to be patient. This morning I awoke to a cloudy blue pool!! I guess that last dose of 4 gallons of liquid chlor was enough to turn the tide. Just tested the FC and it's still above 60+ppm as near as I can tell (had to dilute 20:1 with RO water to get in range of my old kit) so should I just wait and let the filter keep running? Hate to add any more chlorine with that much already there. Of course, now that I have blue, I want clear.


    Quote Originally Posted by duraleigh

    1. Your CYA is still w-a-a-a-y too high. You are beating your head against the wall trying to keep that pool clear when the CYA has essentially rendered your chlorine ineffective. I was extrapolating from the chart posted by chemgeek that said for a CYA in the 140+ range I would need a shock level of around 54ppm FC and a maintenance level of around 16ppm FC. I think that's doable with liquid chlor in the short term (couple of months) until I can drain and refill.

    You really need to get your CYA into the 40-60 range. That may require that you drain 1/3 of your pool and then drain 1/3 again and possibly even again but, until you get your CYA down to a manageable level, you will continue the same frustrations you currently have. I'm told I can't expose that much plaster even for a short time with the temps where they are now (mid 90's) without damage. I have to wait until the ambient temps get into the 60's before I can drain.

    2. Stop using Cal Hypo. Your CH is already too high and you are only driving it higher. Continued use will cause you some secondary problems that can/will cloud your water. Understood and agreed. Only liquid chlor from here on out as best I can. My water's still cloudy, wondering if that's from dead algae, or the CH being so high. How can I tell? Should I try a flocculant, or just wait?

    3. Stop using Tri chlor. That's what has driven your CYA to it's present level and it's continued use will only exacerbate the problem. Already know about the trichlor, haven't touched it since I got the test back with the 200+ CYA, and plan to never use it or dichlor again. Big problem with keeping water balance here in AZ, as evaporation loss tends to concentrate CYA, CH, and TDS much more than splash out can ever offset. You pretty much have to plan on doing a complete water replacement every 2-3 years because of that and the fact that our tap water starts out at about a 15 grain hardness to begin with.
    Thanks again for all your help!

  5. Back To Top    #5

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    Re: 50+ppm FC and Pool Still Green??

    You can drain and refill simultaneously and expose no plaster (not sure why that's an issue, but.....) simply by siphoning from one end on the bottom and filling from the other end on the top.

    CYA in the range you're in is beyond the scope of my experience so I cannot comment on the source of the cloudiness.
    Dave S. - Forum owner
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

  6. Back To Top    #6

    Re: 50+ppm FC and Pool Still Green??

    Drain out ALL the water and start over.

    That solved ALL my problems overnight.

    IMHO

    Hal
    "Whatever happened to the guy who drained his whole pool?"
    27,000 gal plaster in-ground
    Compupool 40k SWG from eBay - works great!
    Polaris 380
    Hayward DE
    1.4 HP Hayward Northstar pump
    Two FAFCO Solar Bear panels now heating the pool!

  7. Back To Top    #7
    JasonLion's Avatar
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    Re: 50+ppm FC and Pool Still Green??

    Very high CYA levels can be managed by using very high FC levels. If you really got FC above 50 then it is likely that you have killed, or are in the process of killing, all of the algae. It can take the filter up to a week to clear the water after the algae is all dead.

    Fairly soon you are going to need to lower your CYA level. High CYA levels present a number of challenges. For example the standard PH test is essentially useless when FC is much above 20, and not completely accurate when FC is above 10. With CYA around 150 you are going to need to keep FC at 12 or higher, preferably higher, at all times. Which is going to make measuring the PH a little tricky.
    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

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