I Made a Mess out of my SLAM. Need advice

[daskiker]

Started battling algae April 30th, but not consistently until the last 6 days. I have a 36,000 gal pool (in Alabama) and use a TF-100 test kit. I no longer have the numbers when I started this battle, but I recall all the numbers being in an acceptable range to start the SLAM process. When I began, the vinyl liner was covered with green algae. I will point out that I watched it spread from a spot in the shallow end that never gets sunlight. This "spot" has been with me since last summer and remained all winter long. (I never did get a hold of it last summer). Imagine about a 2 inch wide green spot that follows the floor of the pool against the wall that never gets sunlight. Anyway, I point that out because this seems to be the origin of the problem and this spot is impervious to any attempts to brush it away.

So, I start the SLAM, and I made multiple mistakes, so I am going to fast forward until I got a reorder on my FC test kit and got serious about brushing and really checking things. This started 6 days ago. Importantly, after reading a lot and looking at images on the web (and based on my experience of no algae problems for years and then suddenly recurring algae problems as soon as I drop the ball in testing), I am (now) convinced that I have a mustard algae problem. However, when I first started the SLAM I tested my CYA (45) and sought to shock the pool at a level that I believed would be higher than needed (I chose FC=18). The first few days I did not check it enough, because I kept seeing readings that would go below shock value (FC=16). After two days of lazily checking, I started checking constantly. Now, here is what may be an important variable. Once I thought that I had mustard algae, I initially interpreted the "mustard shock" value as the value that I had to maintain. (I now know that you do this for 24 hours after passing the tests). So, for about 3-4 days I had the FC in our pool at around 30. One time the reading was FC=42.

Yesterday,I finally saw the proper procedure for dealing with mustard algae, but I figured that since the FC was so high I would go ahead and hurl all of the pool equipment into the chlorinated water. So this is what I did this morning. I let everything marinate in FC=42 water for two hours and then pulled it all out. Afterwards, I vacuumed out the pool and backwashed it. (Note when I did this there were mud-loooking stains on the walls in spots, and I was mostly vacuuming what looked like sand). Because so much water was lost, I filled it back up with tap water. My mindset was that I had seriously over chlorinated my pool and that I was going to damage the liner. I thought that there was no possible way to go from FC=42 to a reading below shock value (FC=16) any time soon. I decided to conserve my powder (Edit: testing powder--I've not put anything but bleach in the pool) and chemicals (edit--testing solution) and await tonight's reading. Honestly, I was thinking along the lines of passing the overnight chlorine loss test. After all, I've dumped untold gallons of bleach in the pool since I started.

Below is tonight's situation:

FC: 12
CC: 0
TA: 50
CYA: 45 (didn't test again, but this is what it was when I started)
PH: 7.4

Impervious stain is still there, unaffected. I've brushed it a thousand times. Last year I remember trying to rub Vitamin C on it for some reason. Water is crystal clear. I spent a ton of time today brushing every square inch of the pool. I will note that when I brushed a crevice below the steps I did see a big plume of (what I think is) algae come out of it.

Questions:

1. Why is my TA now so low? Should I do anything about it or is this just a false reading due to the SLAM?
2. If I one day pass the OCLT do I still need to do the 24-hour "mustard shock," given that I have erroneously been doing this for days now?
3. What the heck is this stain? I promise you it looks just exactly like algae. Imagine a line on the floor of the pool that hugs the wall. It starts out algae green/yellow and then gradually turns into just a blur.
4. I read somewhere on here that dead algae is "colorless." I am getting up every morning and seeing what looks to be lines of sand in the pool. It is mud brown.
5. Can throwing pool equipment into the the water cause FC to drop 30 points, or is this more likely indicative of a continuing algae problem more generally?

I apologize that I went off on the SLAM half-cocked and am not a good representative of the process being espoused here. I guess I got cocky and a little lazy. However, I would appreciate any advice here. My Plan: Keep shocking until I pass the OCLT and ignore the fact that I will still have the impervious stain in the shallow end. Then, I will keep the FC at double the minimum rate until the stain (hopefully) disappears in a few weeks. Does this sound reasonable?

 

[PAGirl]

My dead algae looks brownish. (My SLam is in limbo) Have you been using a lot of MA to lower PH recently? And when you mention saving powder, are you referring to the CL testing powder? (Saving it)

 

[JVTrain]

Sounds like you've committed to SLAM procedure in force, so that's good! Have you been performing the SLAM by chlorinating with only liquid chlorine AKA bleach? Powdered chlorinators will either rapidly raise your CYA at the same time or increase your CH, depending on the type. Dichlor = hypochlorite and CYA. Cal-hypo = hypochlorite + calcium. Bleach = hypochlorite + a little salt. Best to use only bleach. Not sure if you meant reagent powder or powdered pool chemicals...

1. Your TA might be low if you've been using acidic products in your pool such as dichlor for a source of FC. As I said, dichlor adds FC and CYA as well as being acidic. Every time you add acid to your pool of any kind, your TA will decrease. Your TF-100 TA test should not be affected by high FC levels. You could add a few extra drops of the R-0007 reagent to the test if you're performing it at high FC levels. That reagent neutralizes chlorine so extra drops may help at 20+ FC or so.

2. WHEN you pass the OCLT (you will if you stick to the SLAM) you can certainly perform the mustard shock to attempt to knock it out. You may have mustard algae, but I'm not entirely clear on how to identify properly.

3. That stain could be metals or it could be organics. Testing some Vitamin C tablets in a sock, held on the stain for a few minutes will tell you if it's metals. If it fades with Vitamin C, it's metals. If that does not work, try holding a trichlor tablet on the stain for a minute or two. That will fade organics stains. Left too long and it will bleach your liner so not too long. If you continue the SLAM and regularly scrub that area as you have been, it should go away if it's organic/algae.

4. Dead algae tends to be colorless or gray dust on the bottom. Live algae can look brown, yellow or a light green color. I get lots of dust/dirt in my pool (live near farm fields and it's been a dry, windy spring...) and it looks brown or tan.

5. Depending on what you threw in the pool for equipment, that could have consumed some FC if it was dirty or had residual algae on it as well. Likely a combination of continuing algae and the equipment... depending on what it was and what condition it was in. If you have any ladders or fixtures, removed them and scrub with a brush and dilute bleach solution, maybe a cup of bleach in 5 gallons of water. Scrub them well, then rinse with tap/hose water.

 

[daskiker]

No, I have added nothing but bleach since I started the SLAM. Sorry for being unclear, but I was referring to the little cup of powder in the testing kt. As many times as I need to test, I wanted to conserve it!

 

[daskiker]

Thanks for your reply JVTrain. Sorry to be unclear, but I was referring to the "powder" in the test kit, not various pool store chemicals. I have only put in bleach (8.25%) since I started the SLAM, so I am not sure why the TA reading is down so much.

The Vitamin C test that you described is what I recall doing last summer to no avail. The stain was unimpressed. It seems to be some type of bionic algae that I hope to fade to nothing over time by keeping my FC 2X what the minimum recommended setting is once the SLAM is complete. Does this make sense, or should I attack it more directly? Or, should I not consider the SLAM complete until this spot goes away?

 

[daskiker]

I am at an interesting crossroad in my cobbled together SLAM. First off, I started the SLAM with a CYA of 45 and designed the whole process around that value. As I said in my initial post, I had several days of very high FC, thinking that the "mustard shock" was a value to be held throughout. Anyway, as far as NEW information, here is what has happened:

- I checked the FC last night after dark and it was at 23.
- I woke up this morning and the FC was at 23. CC=0. Water is clear. BUT, there is still that algae stain on the shallow end floor, hugging the wall. The darn thing has survived days of FC in the 30s and multiple attempts at scrubbing.
- So, I thought I would ask you guys what to do about this. Do I stop the SLAM? My instinct is to stop it and keep the FC higher than recommended over several weeks until (hopefully) the stain will disappear.
- Before I posted this question, I thought that everyone would want some final, to the minute numbers. Here they are, after about 3 hours of sunshine:

FC: 17.5 (drop of 5.5 in 3 hours)
CC: 0
TA: 70
CH: 90
CYA: 0 (I have NEVER had this happen. I poured the whole bottle in and could still clearly see the dot. I checked it again. Same result)
PH: 7.5

What happened to my CYA?

I am not positive on even the questions to ask. I've got a clear pool. I've been over shocking it for mustard algae. At some point in the process, I began losing CYA (and therefore needing lower FC values) and nonetheless dumping much more bleach in than required. Somehow, through all of this, my TA rose 30 points....and I still have the stain in the corner that kicked off the whole process. Again, with that stain, I tried that Vitamin C test LAST SUMMER to no avail. Last summer I did not have a swim season due to constant algae battles. This, and after much research, led me to be convinced I was dealing with mustard algae in the first place.

Vinyl liner. 36,000 gallon pool. TF-100 test kit. Hayward pump. Sand filter.

Any advice on what to do now? Without any guidance, my plan is to go throw some pucks in the chlorinator and get my CYA back up again. Ignore the stain for now, and keep a sharp eye on my FC levels and maintain it every day. Thanks for reading!

 

[JVTrain]

How long ago did you measure the CYA at 45? CYA can break down slowly over time in the presence of high FC levels, but if it's only been several weeks, that's extremely unlikely. There are a couple other ways to lose CYA. One obviously being water replacement. The other may happen if the FC drops to zero for a period of time, even a short period in some situations and bacteria consumes the CYA, converting it to ammonia. Did you have a period of massive chlorine demand anywhere in this process?

As far as the stain that appears to be the source of the algae, I would try applying a trichlor tablet directly to the stain if you can. I'm not sure on your location but it might be tough to get in the pool to do this. (You should update your location in your profile and add the details to your pool, testing methods in your forum signature.)

Using granular CYA to get that back up to 30 ppm is probably a better option than pucks in the chlorinator to get your CYA up quicker.

 

[daskiker]

Thank you for your help. I measured the CYA a bit less than 2 weeks ago once I decided to start the SLAM. To answer your questions about the CYA loss:

- Three times during the SLAM I vacuumed the pool to waste and then refilled with tap water what I had just hosed out.

- The one instance where there was a pretty significant use of FC was when I gave all of my pool equipment a mustard shock bath. When I threw the Polaris, the hose, the poles, etc. in the water the FC went from 30 to 12 in short order. I then quickly got it back up by adding more bleach.

- I will put some granular chlorine in now.

- Yes, I can easily reach this stain, so I will lay a couple of trichlor tablets on it so that I can cover the whole thing and see what happens.

- I will update my signature when I next post an update on the situation. Again, thank you!

 

[frustratedpoolmom]

I've never lost CYA while shocking pools. I've oxidized millions of gallons of ammonia...
Algae, of every type ALWAYS, ALWAYS BRUSHES OFF. Black Algae is unheard of in vinyl liner pools. It can grow in the gasket/stair strips by the stairs in some pools if the stairs are fiberglass, for example. But even then, with the right procedure and diligence, it can be removed.

DO NOT LAY TABS on a vinyl liner!!!

Whatever that area is you've been dealing with, it does not sound like algae to me... and I've seen just about it all. It may be some kind of staining.

I would recommend you start keeping a daily log of testing, journal so to speak, to eliminate guess work or testing error.

I've found that this whole learning process of pool ownership, pool store advice, TFP methods, can be very overwhelming for our new guests. Your TA is on the low end but not a pool crisis by any means.

 

[JVTrain]

Keep in mind, when I recommended putting a trichlor tab on the liner, I was not advocating putting it on there and then going out for dinner. Only for a minute or two by hand to see if the stain fades and to confirm that it's an organic stain. If it does fade then you know for sure it's organic and should continue to fade as you maintain your sanitation.

 

[daskiker]

Thanks, frustratedpoolmom. I appreciate your experience and taking the time to weigh in on my problem. Believe me, I am open to the possibility of this stain being virtually anything. I would like nothing better than for this to be a permanent, yet innocuous, stain on the pool liner that is not algae. The only reasons that I have for referring to this as an "algae stain" are: 1) it looks like a typical, garden-variety, yellow-greenish algae stain, 2) the stain is on the floor by the wall which is located in the only spot in the pool that hardly ever gets sunlight, 3) when I do get an active algae outbreak, like this time, it first reveals itself by that particular stain becoming greener and then expanding further along the same wall and around the foot of the steps. This "new algae" is then indistinguishable from "the stain". It all blends in. But, the "new algae" can be brushed off while the stained part cannot be brushed away.

In terms of the CYA loss, all I can say is that when I start a SLAM, I take measuring the CYA extremely seriously, given that this is the measure that determines the proper FC level. When I measured pre-SLAM, I wrestled with the value. "Is it 40 or 50?" I asked my wife to look at it. We decided on 45 as "the number". Today's measurement was very different. Today, you could simply pour the entire solution in the tube and the black dot was crystal clear. I repeated the test and got the same thing. I am not ruling out testing error, but I tried to be very careful; particularly on the CYA measurement.

As far as what to do NOW, I am assuming that you are recommending that I disregard the stain, as it is almost certainly not algae. Also, lets assume that there is not currently, nor has there ever been. an accurate CYA test done on the pool. If I have a FC=23 at night and a FC=23 in the morning with no CC, is the SLAM over, no matter the CYA? If the stain is not algae, then wouldn't you be saying that I should stop the SLAM today?

I hope this is not coming across as argumentative or defensive because that is not how I feel or what I wish to convey. I just have dumped countless dollars worth of bleach, hours of brushing, etc. and I do not wish to have to do this again. I feel like I need to make the right decision and am just trying to lay out all the facts as I believe them to be.

 

[daskiker]

I tried the pucks on the liner and I did not notice anything dramatic, though it is possible it made a dent in the stain. I did conclude; however, that it has faded some since I started the SLAM. Of course, that could be true for the liner as a whole, given how out of whack my FC has been!

Does anyone have a clear opinion on exactly what I should do next? Recall that this morning I passed the OCLT, but my reading of CYA went to zero. Further, my latest FC reading (taken just now), was 11. So, if my initial CYA reading was to be believed, then I am under shock value right now and would need to add more bleach to keep going. (Note a loss of FC=12 on a bright, sunny day in Alabama).

In the absence of any opinions to the contrary, my plan is to 1) figure out how much chlorine grannuals I need to raise my CYA to about 40 over time and hurl that into the pool, 2) consult my CYA / FC chart to determine what level of FC is needed (not the shock level, just the normal one) and look to keep my FC levels at double this amount, starting now. The hope is that over time this stain, if it is algae, will fade. If it doesn't go away in about a month, I'll assume it is not going to be anything troubling, just ugly to look at.

 

[JVTrain]

I would go to normal maintenance mode with your FC levels and keep and eye on the stain. It should fade over time and keeping the FC slightly above recommended maintenance levels may help accelerate that. Keep and eye on the area for algae and brush often in that area. It might be an area of poor circulation leading to locally lower FC levels. Brushing and trying to adjust your returns for better flow would help.

 

[cowboycasey]

Hey there, looks like you have been on a SLAM for sure.. here is the problem I see...

1. If your CYA is truly 0 now your fc should be no more than 2... it can bleach out your liner with no CYA..

2. if no CYA, put the amount of CYA that poolmath says to get you to 30

3. you can keep your FC at SLAM level as long as you want, but I would not stay above that level and if you do go to Mustard level it should be for very little time, you do not want to stay up there for long..

I believe you probably had your CYA eaten and you had ammonia that you have already broken because you are holding chlorine

It is your pool so these are only recommendations

 

[frustratedpoolmom]

My reasoning is this, I don't believe your CYA if you had that level of "45" converted to ammonia WHILE adding chlorine because if that were the case, you would not see the high FC levels you reported. You would only see high CC levels, and a FC of less than 1. That's just the way the tests behave when oxidizing ammonia.

More likely it was lower than you originally thought, and through dilution it is unmeasurable around 20 or so. I would suggest adding enough CYA to reach another 20ppm and retest in a week.

Live algae definitely behaves much different that old organic staining and will not contaminate the pool with a new algae bloom... what you are describing is something different. Any chance you can snap a pic?

- - - Updated - - -

Yes, do as you said in your last post and you may have to learn to live with it. My organic staining that I had for 5 years eventually faded permanently after following the advice here at TFP.

 

[daskiker]

Thanks so much for the input.
I have added some chlorine grannuals to the pool in an effort to increase the CYA, but I think I am going to stop adding further chlorine and just go get some stabilizer for the job. As someone posted above, if I am to believe that my CYA is indeed close to zero, the FC should be at 2, not 20. So, tomorrow, I plan to leave the pool alone and let the FC go down. If it is truly low CYA, then the bright sun should do the job in short order. On the CYA issue, I am personally beginning to wonder things like, "maybe the CYA solution just at some point rapidly breaks down into uselessness and this just so happened to occur in the middle of my SLAM." Other than that, I am at a loss. All I can say is that I did my best in testing the CYA both before and after, and the difference was not subtle. Something happened to the reading.

I also dug out a waterproof camera. I plan to don the swimsuit and dive down in the pool and get a close up shot of this stain so that you all can see exactly what I am talking about. I took some pictures today standing over it, but they aren't worth posting because they weren't that clear due to the constant shadow over the stain. I could well be wrong, but I predict that you will see the picture and at least be able to say, "Yes, that does look exactly like algae, but it can't be, can it?"

As far as possibly bleaching the liner, I can live with that. At this point, the only thing I care about is standing over the corpse of this algae and raising my hands triumphantly in victory. I just don't want to lose a swim season like I did last year. Plus, having held a mustard shock for several days (possibly with a drastically overstated CYA as my baseline), I don't know if I could do significantly further damage than I've already done to the liner. I'm proud of the liner; it's held up as well as it could be expected to, given what I've put it through the last two weeks.

Again, I really appreciate you all taking the time to respond. I'll update the situation sometime tomorrow!

 

[frustratedpoolmom]

I have never seen CYA behave that way but I suppose anything is possible?

I love your attitude Hang in there!