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Thread: Liner stained yellow but 0 metals and 0 algae

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    Question Liner stained yellow but 0 metals and 0 algae

    I have totally stumped the pool guys here so I am asking for help. I have been reading your forums and have gotten helpful hints but I still have problem. This has been an ongoing saga and I will try to be brief. When opening pool in April the light was shattered over the winter season and pool water dropped (leaked out) so the water level was now at the lower ˝ of the light. Fixed broken conduit and repaired light. Tested water adjusted chemicals. Clear for a while and then cloudy and real difficult to clear. Was told to change sand in filter (sand had not been changed for about 7 years). Started to clear, shocked heavy because low chlorine (all levels normal) and 2 distinct yellow water lines appeared. One from where the water had dropped this winter after light broke and a new line at current level. Water was tinted slight yellow. Looked more aqua because of the liner. Metal right? Tested negative. Went ahead and did an ascorbic acid treatment anyway. Cleaned up yellow liner like a dream, added Metal Free and water no longer yellow but had algae because of low chlorine. Treated that and had a to shock for the Yellow Out treatment and what should appear again…the yellow lines and distinct yellowing where the water hits the shallow end on the floor and an overall aqua color. Just lowered chlorine again, treated last night with 3 pounds of ascorbic acid, put on recirculate and pool looks beautiful this morning. Of course chlorine is at 0 again. What can be in this water to do this? We have no heater and use city water. Two of my next door neighbors have pools with no problems. Could there be any way the “gunk” from the light could have contaminated this water with some kind of mineral? I mean it sat all winter with water running in all parts of the light. I have had this pool for 10 years and have always had crystal blue water. Our house is fairly newer (20 years) so I don’t think it is a pipe problem.

    Pools stats: 16x36 underground vinyl liner
    Most recent readings today:
    Free and total Chlorine 0
    Calcium hardness: 260
    Cyanuric Acid: 40
    Total Alk: 110
    PH: 7.1
    Copper: 0
    Iron: 0
    Total Dissolved Solids: 900

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    JasonLion's Avatar
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    Re: Liner stained yellow but 0 metals and 0 algae

    Welcome to TFP!

    You have iron in the water. Ignore the iron test, it is often wrong. Yellow stains that are removed with ascorbic acid are iron regardless of what the test says.

    Metal Free is not one of the sequestrants we recommend. Sequestrants based on HEDP, phosphonic acid, or phosphonic acid derivatives are the most effective. ProTeam's Metal Magic and Jack's Magic The Pink Stuff (regular), The Blue Stuff (fresh plaster), and The Purple Stuff (salt) are some of the top sequestrants. You can also find many other brands with similar active ingredients, some of which are noticeably less expensive.
    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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    Re: Liner stained yellow but 0 metals and 0 algae

    Thank you for the quick reply! Where can it be coming from? And why all of a sudden? Do you think I would benefit from totally emptying pool and starting all over again? I hate to do that but wow this had been an expensive summer already so... Sorry about all the questions.

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    JasonLion's Avatar
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    Re: Liner stained yellow but 0 metals and 0 algae

    If there are low levels of iron in your fill water, it will slowly accumulate in the pool. Eventually, often years later, there gets to be enough to cause stains.

    Replacing some water might well be a good idea, but only when the stains are removed and the iron is in the water. I wouldn't replace all of the water, replacing a little less than half should be enough to get the level back down to where it doesn't matter.
    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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    Re: Liner stained yellow but 0 metals and 0 algae

    Thanks I will do that. Hate to keep bothering you but I have another question. So the local pool company told me to add put the Metal Free in today ( I did this morning) and algaecide as a preventer tonight and then tomorrow up my PH by adding a pound of soda ash and start with liquid chlorine the following day. So I was up to the algaecide adding part which I did. Took the dogs for a walk and came home an hour later and...pool so cloudy I cannot see the bottom ( but the water is still blue). Why is the algaecide making the water cloudy? Here I go again. I swear it is one step forward and 5 steps back. I have only had clear water maybe for a total of 2 weeks this season and not consistent either!
    Pools stats: 16x36 underground vinyl liner
    Most recent readings today:
    Free and total Chlorine 0
    Calcium hardness: 260
    Cyanuric Acid: 40
    Total Alk: 110
    PH: 7.1
    Copper: 0
    Iron: 0
    Total Dissolved Solids: 900

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    JasonLion's Avatar
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    Re: Liner stained yellow but 0 metals and 0 algae

    Metals plus sequestrant often cause cloudy water for one to three days.
    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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    Re: Liner stained yellow but 0 metals and 0 algae

    But it was crystal clear after the sequestrant was added. Looked beautiful all day. This happened within 1 hour after the algaecide being put in. What would you do? Should I add the soda ash tomorrow and then proceed to slowly raise the chlorine level the following day? I am having a flash back that by this time next week I will have aqua green/yellow water again and I will be repeating this disaster all over again : (

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    JasonLion's Avatar
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    Re: Liner stained yellow but 0 metals and 0 algae

    If you don't find a better sequestrant, it will indeed do exactly what it did before.
    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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    Re: Liner stained yellow but 0 metals and 0 algae

    I plan on ordering the Pink Stuff but it will take a week to get here.What would you recommend in the meantime? Should I continue to balance water? And add more of the sequestrant that I have on hand? Right now I have 0 chlorine according to the readings and I'm thinking algae will be next.
    From reading your replies I'm still not sure why it is the sequestrant that made it cloudy rather than the algaecide? The timing seems off.

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    Re: Liner stained yellow but 0 metals and 0 algae

    The timing on the algaecide is interesting, but algaecide just about never makes the water cloudy. Meanwhile, cloudy water about 12 to 36 hours after adding sequestrant is quite common. There are other possibilities, like algae, but sequestrant really seems like the most likely candidate.

    You need to add chlorine or algae will take over. The trick is to add chlorine only until the FC level is one or two, and not more than that. It may well take quite a bit of chlorine to get to that level, as you still need to burn off any remaining ascorbic acid, which uses up chlorine fairly quickly. Then raise the FC level very gradually over the next few days. If you keep the PH low (7.0 to 7.3) and FC on the low side for your CYA level you should be able to avoid the green coming back.
    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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    Re: Liner stained yellow but 0 metals and 0 algae

    Thank you! I will add some liquid chlorine tonight. I was going to try just adding 6% bleach over the next couple days. I've used you calculator and think I have it figured out! Thanks again for the help. Will keep you posted and the pool is back to clear now!

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    Re: Liner stained yellow but 0 metals and 0 algae

    Just on a curious side note. I looked up Natural Cemistry Metal Free MSDS and is it possible that the only active ingrediant is Citric acid?! https://media.nat.cm/filer_public/20...ds_-_jul14.pdf

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    Re: Liner stained yellow but 0 metals and 0 algae

    There are lots of things that don't have to be listed on a MSDS, because they are safe. Since citric acid is only 1%, I assume there are other active ingredients. Whatever they are, they are not as effective as the sequestrants we recommend.
    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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    Re: Liner stained yellow but 0 metals and 0 algae

    Thank you for all of your help! I just had my water tested yesterday and the results were looking good. I have had crystal clear water for 4 days until this morning. Woke up to cloudy water ( cannot see the bottom of the pool) and what looked like a small amount of yellow algae on the bottom of the shallow end ( is there really a ever a small amount of algae). SO I am thinking I need to really shock it but worried about the metal returning. Have not received The Pink Stuff in the mail yet so put in some Metal Free just now. What do you think the best method of ridding the algae and clearing the water would be? I actually did not use shock previously to get Chlorine up but liquid bleach. Plus how soon after a sequestrant can I add the bleach?
    Free and total Chlorine 2
    Calcium hardness: 240
    Cyanuric Acid: 50
    Total Alk: 80
    PH: 7.2
    Copper: 0
    Iron: 0
    Total Dissolved Solids: 800

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    Re: Liner stained yellow but 0 metals and 0 algae

    You should never let your FC get below 4 ppm when your CYA level is 50 ppm. Otherwise, algae can grow faster than chlorine can kill it.
    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"

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    Re: Liner stained yellow but 0 metals and 0 algae

    I did not know that! The problem I have is trying to keep the chemicals at a level so the metal staining does not occur. So what would you suggest I do?

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    Re: Liner stained yellow but 0 metals and 0 algae

    It's a higher pH that would cause staining, not the higher FC level itself. As for the proper FC level for your CYA level, I suggest you take a look at the Pool School including the Chlorine / CYA Chart.
    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"

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