Ho wow! How often are your testing/raising FC during the daylight hours? do you see a similar FC loss during the day? Your PM Logs only show the addition of chlorine and not the test data. It shows a range of 8-12 hr between LC additions.
Persistent Algae Spots
- Thread starter Haxzit
- Start date
Only testing FC about four times a day. Morning, afternoon, twice in even to raise to slam level and once more to log level before bed. Following slam per pool math. Just took it back over on Saturday. Because of work had wife just adding enough bleach in the morning and night to maintain slam level.
Did check cya again yesterday and was closer to 60 so currently maintaining 24ppm. But last two overnight tests show a 6ppm loss. Frustrating because I can not figure out or see what is causing the loss. I’ve cleaned and scrubbed everything. Reading in the other post for suggestions. Only change in routine I can find is test more frequently and brush more. Nylon brushing I don’t see anything like dust cloud. I do get a cloud using a metal brush but read it’s not good for PebbleTec. But I did use the steel brush lightly, last week, all over just to be sure.
Ok that makes sense and with CYA being higher than originally thought that may contribute to the persistent loss of FC. Now that you are back on a 4x a day schedule, you may see a better result in your Overnight Chlorine Loss Test
Day 18 of slam. Patience is wearing thin. Still losing 6ppm overnight. Trying to figure out what is causing the loss. Need thoughts on an experiment to see if this is valid. I saved a water sample from the night test and tested the sample in the morning. Agitated the water to mix before testing. I had the same 6ppm loss as the pool reading. This doesn’t make sense to me, as it was in a sealed container separate from the pool. So my pool water is contaminated? I have scrubbed everything I could possibly think of. Only think else I can come up with is, maybe something living in the unground plumbing? Thinking of tearing apart the de filter again today and searching in there again. Read in form a member found a faint layer of algae in filter panels and housing. I already thoroughly cleaned it a week ago but don’t find anything visible. Another question if someone knows, how much damage am I causing using a steel brush on peebletec. I used it on a couple areas with some discoloration, possibly algae, I don’t know. Surface color is difficult to see if the is some algae growth as small as the stones imbedded in the surface to see. Always get an underwater visual cloud when I use the steel brush but possibly just a cloud of plaster dust which I don’t believe is a good thing. Always use a nylon brush daily but never see cloud of debris. Keep search forms for similar issues such as mine but not having much luck. Just doesn’t seem like there is a light at the end of this tunnel. If this goes into next week without improvement think I might just abandon this. This is exhausting. I’m at the point now to just live with the small spots of algae that appear every two to three weeks and just go back to removing those by hand. Definitely a cheaper option then the money spent running equipment 24/7 and $120 on bleach. Apologize for the negativity but every pool is different and I believe mine is just stubborn and just something I’ll have to live with. On a positive note my pool has always been clear and beautiful thanks to trouble free pool. Just can not pass an overnight loss test. So I believe it’s still a win having a pool so clear it sometimes looks like there is no water in it.
How sure are you of your testing procedure? Just trying for rule out obvious stuff. Try cleaning the test vial with alcohol and rinse really well and try again.
It would also be super helpful if you could log the test results in pool math and not just the chlorine additions. Otherwise it’s hard to give advice on test data we can’t see. Sometimes really dumb mistakes like doubling the drops instead of halving them can get people.
Something is consuming chlorine and it you don’t kill it off, it’ll just keep growing.
InyoRich
In The Industry
- Oct 18, 2023
- 141
- Pool Size
- 9000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pureline Crystal Pure 40,000
I completely sympathize with your frustration over this. I don't see it in your signature and I'm not 100% sure this would cause the issue, but do you have a UV sterilizer or ozone generator in your system somewhere? Is there a sprinkler nearby that is using lake water for irrigation or a lake fountain that might get some overspray into your pool? Do you have a solar blanket on the pool? It is baffling that you are still losing that much chlorine overnight.
These are all really good questions. Pool covers are a common theme with extended SLAM’s.
I am very anal over testing. I have used up so much regent materials. I sometimes don’t believe the results and test three or four times to be sure I’m coming up with the same results. I even have the sample device from Taylor to be sure I have exactly 10ml. I found using 5ml sample to be off by consistently 1-0.5 ppm but does save on regents. As far as logging test results I’ll try to do that from now on but if I just do just FC, it will flag the others as being off. That was the main reason for not logging data. But trust me when I say I’ve increased testing to about two hours during the day and always adding bleach to 24ppm. Just spent couple of hours and tore down the de filter again. Scrubbed both upper and lower filter housings and all seven panels. Getting ready to test levels again. Including cya since I backwashed before cleaning filter. I have no cover or anything else in pool. No other equipment than what is mentioned in my signature. Have cleaned behind light niche including tearing it apart and cleaning seal and frame, main drain, skimmer, and return fittings. If this doesn’t change any of the readings I’m at a loss and don’t no where else to look or clean. I have now become a full time pool boy and not get anything else accomplished. Think my wife is getting ready to leave me because of my intimate relationship with my pool. 
Ok so after filter maintenance just got a dramatic drop in cya in a week. From 60ppm down to 15ppm. Tested twice to be sure. Adjusting to about 35ppm. FC is at 15ppm. So I guess I’m still good for now. As long as I get the cya up. And yes I logged test results.
STOP! Do not add CYA. You can’t measure 15ppm CYA. How did you get that number?
Can you describe exactly what being anal means as far as testing goes. How are you keeping track of test results? When you are doing the OCLT, you are adding 12 drops to make it go from pink to clear?
It’s not possible to lose that much CYA in a week unless you have ammonia, or a bacteria that eats CYA. There’s a process for checking both on the site here. You should look up the details, but I think it goes soemthing like adding 10ppm of FC and checking the FC 10 minutes later.
It’s not possible to lose that much CYA in a week unless you have ammonia, or a bacteria that eats CYA. There’s a process for checking both on the site here. You should look up the details, but I think it goes soemthing like adding 10ppm of FC and checking the FC 10 minutes later.
Can you explain more what that means? Why would the other test results be flagged as being off? Can you post a full set of test results just right in this thread?
I used the test in the Taylor kit 2006C and got almost no reading. So I resorted to the Taylor K-1760 kit and got 15ppm.
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Being anal means when I test and take my time and make sure I’m being as accurate as humanly possible. I’m not a newbie and have does these tests before. I even re-run the test if the results seem a bit off just to make sure I didn’t miss count a drop or something. My least favorite test is the cya test. Just seems there is room for error trying to get it exactly on the line. The more accurate test, using the Taylor K-1720 uses a bigger sample and has to fill to the neck of the bottle which seems confusing instead of using a line. I’ve tried it several different ways with very small variations in ppm. So I just round to the closest ppm. Now I did dump some pool water today which maybe a cause of the drop. I’ve never loss that much but did test twice on both occurrences prior and today. I have since tested and I’m currently at 30ppm. If I’m successful after slam I will raise it back to 80ppm.
Using the pool math app I just logged FC, CC, CYA and water temp. The app tells me that PH is out of range but I didn’t test for that because of the slam. Thats what I was referring too. I apologize for not regularly logging test data. I have started logging as of today so you guys can see and just ignore the notifications on the tests I didn’t do. Previously was using the app to tell me how much bleach to add after testing to maintain.
OK I get it now. It’s just you haven’t ever logged test results before and so it’s telling you that pH is out of range? You can do all the tests except for PH during a slam and that would solve the app issue.
Have you tried cleaning the chlorine test tube with alcohol? Some people report getting CC’s with a dirty tube and since we’re grasping at straws here, maybe it’s something worth trying.
Have you tried cleaning the chlorine test tube with alcohol? Some people report getting CC’s with a dirty tube and since we’re grasping at straws here, maybe it’s something worth trying.
I guess you have a small pool so it’s possible that the cya dropped if you exchanged half the water. I would avoid raising the CYA back to 80ppm if you’re having algae or chlorine consumption problems. Keep it between 30-50. Maybe during summer you can try increasing it.
I will try cleaning the sample tube or just get a new one.. I have several. Crossing fingers that cleaning the filter again and now having the cya in a more acceptable range for slamming may help achieve a better ONLT.
I shouldn’t increase my cya once the slam is over? The recommended level for a swg is 70-80. I get leaving it low while I’m using bleach for the slam. I won’t raise it until I get a successful ONLT and end the slam.