A pool that hates chlorine

[RLP]

Your conduit for the light is probably 1" pvc.

They ran my conduit 18" below grade to my equipment pad, before I knew better. So my conduit is constantly filled with pool water that doesn't get circulated . Yours may be the same.

100' of 1" pvc holds around 4 gallons of water. The algae could be hiding there.

 

[FrankieKat]

Are you pulling the dolphin after every cycle and rinsing it and the filters off? I would.

Not every time, but probably every other time. Good point, can't hurt to just take the extra few minutes to do.

Is this the light?

If that's not it, it's darn close. It's a multi color light one. The pool was installed by the previous owner so I don't have full records of all of the pieces to be 100% sure. The question is how difficult or possible it is to remove for cleaning?

Removing/cleaning drain covers might be an interesting trick... 7ft down and I don't really have any good goggles or anything for diving. I don't want to break anything either... Would they just need to be pryed and snap off I suppose?

Also, FC test at 12:15, was about 22 ppm FC, which would be a 8 ppm drop in 4 hours. Now that previous number was calculated based on perfect chlorine, which I know isn't going to be that potent due to my buying two cases made in February, so the actual drop may not be as much. Also worth noting it rained heavily for at least two hours, if that might make any difference.

Gave the skimmer a very good scrub. It was dirty - not sure if it was algae or dirt but either way much cleaner now. I'll deeply scrub the joints of the stairs and work on those fixtures and covers.

Thanks everyone!

 

[FrankieKat]

Your conduit for the light is probably 1" pvc.

They ran my conduit 18" below grade to my equipment pad, before I knew better. So my conduit is constantly filled with pool water that doesn't get circulated . Yours may be the same.

100' of 1" pvc holds around 4 gallons of water. The algae could be hiding there.

Oh boy... So what's the best way to handle that?

 

[kimkats]

You are doing an awesome job so far! @Mdragger88 has laid out your path going forward. Keep listening and doing like you are! You WILL win over the monster!

 

[RLP]

Ugh . Ive been worried about it for a year lol. Ive got around 250' of 1" conduit ran back to my equipment pad.

I think I would get the lights out of the niche, and let them dangle in the pool through each conduit. check the back of the lights and niche for algae.

Then I would use a shop vac at the junction box to suck pool water away from the pool. Problem is the wires will be in the conduit, so need to get a good seal around them. Then maybe inject some bleach into the niche and repeat.

What does your junction box look like? How far away from the pool is it?

 

[RLP]

Removing/cleaning drain covers might be an interesting trick... 7ft down and I don't really have any good goggles or anything for diving. I don't want to break anything either... Would they just need to be pryed and snap off I suppose?

Most have screws on them. There was an instance recently and it was found to be under the grate. It extended the slam for that pool owner.

Also, FC test at 12:15, was about 22 ppm FC, which would be a 8 ppm drop in 4 hours. Now that previous number was calculated based on perfect chlorine, which I know isn't going to be that potent due to my buying two cases made in February, so the actual drop may not be as much. Also worth noting it rained heavily for at least two hours, if that might make any difference.

Dont sweat the date code. As long as the jug wasn't stored outside in the heat and direct sun, it will still have plenty of strength. I have a jug from last year that had a gallon left in it. 15 oz. Raises my FC by 1, and I used it last week and it raised it just about 1.

Keep at it, you are getting there. After all the hard work your pool will sparkle, more importantly be sanitized, and it will be way easy to keep it that way. Its just a bit of a project to get it there. Once you're there you wont have to chase it every week for perpetuity, like most have to.

 

[BDY]

I thought i read somewhere that light conduits were not that conducive to algae because the sun never shines in there and algae needed sunlight to grow

Any truth to that?

 

[RLP]

I saw that somewhere as well. I guess in a perfect world.

But if people are finding it under drain covers, and behind weir doors, Im pretty sure it could be behind the lights and somewhat into the conduit. Heck, I found algae inside of my plumbing from my main drains last year when I was doing some repiping. I never use the main drains, but it was full of stagnant pool water, And algae was adhering to the inside of the sch 80 pvc, which is dark gray. So no sunlight was getting there.

Some pool owners really struggle with eradicating algae. To the point they are really frustrated and suffering. I think it would be worthwhile to check / treat the lights and conduit. It seems like the conduit is only place that isn't mentioned on this forum.

 

[Bperry]

Also, FC test at 12:15, was about 22 ppm FC, which would be a 8 ppm drop in 4 hours. Now that previous number was calculated based on perfect chlorine, which I know isn't going to be that potent due to my buying two cases made in February, so the actual drop may not be as much.

Just a note of encouragement and reminder to not trust the calculation of how much FC is being added by each addition. Once you get closer to being done, you’ll want to actually test what it is as a starting point and then test again in the morning to figure out the actual loss. Sounds like you already realize that but wanted to highlight it as it’s a common oversight.

Also, your earlier note about the pool service not being able to do any harm…you’de be surprised.

 

[RLP]

I would use the more accurate 25 ml test when checking the OCLT.

With sanitized water, If you test the fc shortly after adding it, and you expected a certain amount of liquid Chlorine to raise the ppm (per pool math), and it doesn't, either your chlorine has lost some strength, or your pool volume is not accurate.

 

[sjfrank]

Im new as well and had a similar issue this year, I didn't drain the entire pool, I drained a few inches a day until I noticed the numbers stabilize after adding chlorine. I use both, strip and the Taylor kit. The strips for me are fine in knowing when its probably safe to get back in the pool after a shock. But for maintenance and especially when you think there is a problem use the kit IMO.

 

[FrankieKat]

I would use the more accurate 25 ml test when checking the OCLT.

For sure, when I get closer I will. As it is, measuring 30 ppm with the 10 mL can still take up to 60 drips of the 871 and I'm already running low so may need to ration some future tests. More ordered... Arriving Tuesday.

With sanitized water, If you test the fc shortly after adding it, and you expected a certain amount of liquid Chlorine to raise the ppm (per pool math), and it doesn't, either your chlorine has lost some strength, or your pool volume is not accurate.

I didn't think it would be particularly accurate to measure newly added chlorine since it hadn't had enough time to circulate well (an hour or so?). If I can accurately measure it sooner then that would be much more helpful than relying on calculation.

Since I didn't build the pool I don't have all of the original specs and documents, so I'd relied on a number the pool company that installed it told me "I think it's probably about 18,000 gallons". I just re-measured it and it's 32' x 16', with 6' in the deep end, about 4 1/2' at the midpoint and 3' in the shallow end... So that's actually pretty close to 18k.

Given the need to ration my 871 I'm going to test it every other time now and just keep adding chlorine based on the trend line.

 

[Bperry]

Im new as well and had a similar issue this year, I didn't drain the entire pool, I drained a few inches a day until I noticed the numbers stabilize after adding chlorine. I use both, strip and the Taylor kit. The strips for me are fine in knowing when its probably safe to get back in the pool after a shock. But for maintenance and especially when you think there is a problem use the kit IMO.

I’ll let someone else chime in, but those strips are really not worth the gasoline to go buy them. You may get lucky with them sometimes but if you can’t trust something 100% then there’s no point in trusting it even 50%.

Additional note is that it’s perfectly safe to swim in try pool from your minimum FC all the way up to SLAM level. The “shocking” thing isn’t a TFP endorsed method as it ends up failing with no way to know if it worked or not.

 

[Bperry]

For sure, when I get closer I will. As it is, measuring 30 ppm with the 10 mL can still take up to 60 drips of the 871 and I'm already running low so may need to ration some future tests. More ordered... Arriving Tuesday.


I didn't think it would be particularly accurate to measure newly added chlorine since it hadn't had enough time to circulate well (an hour or so?). If I can accurately measure it sooner then that would be much more helpful than relying on calculation.

Since I didn't build the pool I don't have all of the original specs and documents, so I'd relied on a number the pool company that installed it told me "I think it's probably about 18,000 gallons". I just re-measured it and it's 32' x 16', with 6' in the deep end, about 4 1/2' at the midpoint and 3' in the shallow end... So that's actually pretty close to 18k.

Given the need to ration my 871 I'm going to test it every other time now and just keep adding chlorine based on the trend line.

You really don’t ever need to test more accurately than the 0.5ppm. All of the SLAM criteria is based on that measurement precision. If your chlorine is low enough where it battered whether it was 0.2 or 0.4, you’re in trouble or doing a science experiment.

 

[Saturn94]

measuring 30 ppm with the 10 mL can still take up to 60 drips of the 871 and I'm already running low so may need to ration some future tests. More ordered... Arriving Tuesday.

Unless you are performing an OCLT, with FC that high you can use a 5ml sample instead; 1 drop would equal 1ppm. That will really save on reagents.

 

[FrankieKat]

Additional note is that it’s perfectly safe to swim in try pool from your minimum FC all the way up to SLAM level. The “shocking” thing isn’t a TFP endorsed method as it ends up failing with no way to know if it worked or not.

Really. I've been pretty careful about getting close to this 30 ppm water, like thoroughly washing my hands and arms and anywhere else it might have splashed. I assume I probably wouldn't want my 5 year old who has a habit of opening her eyes underwater to go for an extended swim it? Though we've all been swimming in it this summer with this chlorine resistant algae... So maybe that was actually worse!

 

[BDY]

It’s the CYA buffering effect. FC with no CYA is incredibly more harsh than with CYA

Read this threads if interested

CYA and water chemistry questions

It seems that my account doesn't have the privileges to start a new conversation in order to send a private message to a member. It's been a few days since I emailed the webmaster for support and I haven't received a reply, so I'm trying this approach. I really enjoyed reading the technical...

www.troublefreepool.com

 

[RLP]

Imbalanced ph is what causes eye irritation.

 

[Bperry]

Really. I've been pretty careful about getting close to this 30 ppm water, like thoroughly washing my hands and arms and anywhere else it might have splashed. I assume I probably wouldn't want my 5 year old who has a habit of opening her eyes underwater to go for an extended swim it? Though we've all been swimming in it this summer with this chlorine resistant algae... So maybe that was actually worse!

Your kid is totally fine. No need to wash any more than normal. The stabilizer in the water holds some chlorine in reserve, but the chlorine tests don’t know if it’s reserved or not. That’s why the FC/CYA ratio is so important to get right.

 

[FrankieKat]

Ugh . Ive been worried about it for a year lol. Ive got around 250' of 1" conduit ran back to my equipment pad.

I think I would get the lights out of the niche, and let them dangle in the pool through each conduit. check the back of the lights and niche for algae.

Then I would use a shop vac at the junction box to suck pool water away from the pool. Problem is the wires will be in the conduit, so need to get a good seal around them. Then maybe inject some bleach into the niche and repeat.

What does your junction box look like? How far away from the pool is it?

Here's the junction/controller box. It's fairly close to the side of the pool - would say the closest light is maybe 15 feet, and the others maybe 10 feet further each.