Safe to Swim?

[frankos]

Hi there. This is my 3rd summer with our plaster pool. 32700 gal. I didn't do as well keeping up with the pool year 2 as I did year 1 so I hired a pool guy over the winter. Now he is proving to be unreliable and I have to switch. In the meantime, the salt cell needs cleaned and the pool started growing green algae on the walls about a week ago. His efforts to control have been poor at best. I started a proper SLAM after he left Saturday (he had put enough shock in to bring the FC to about 8, LOL) I'm passing parts 1 and 2 of the SLAM test, but there are stubborn green patches on the walls that just don't want to come off. I've resigned to needing to put a steel brush to them to get them to loosen up and let the chlorine do it's job.

Test Results:
FC: Adding as needed to maintain 15ppm
PH: Muriatic Acid as needed to keep between 7.2 and 7.8. It's starts climbing, I add. It's always climbing because of how hard it is.
CYA: 40ish
TA: 110 last test. that was down from 140 the test before.
Here is part of the problem:
CH: 625!!! I'm trying to decide the best way to tackle this without throwing out half my water. City Water Source tests 110. But city water continually makes PH rise. I have aquariums and if I use city water, I fight constantly to keep PH under control.... just like my pool.
SALT: 4100. This is my bad. I was down around 2600 end of winter, added to bring up to 3600, but after a week it was testing at 2900 so I added 4 more bags. I think the 2900 reading was because the pH at the time was stupid high (probably around 9 based on the pH requirements drop test)
BORITES: 0, although I have the stuff to raise it, But I didn't see the point right now. I tried to keep it around 60 last year to help stabilize the pH. This pool loves 1-2 gal of Muriatic acid a week!

That's the intro. My real questions are:
1. It's it safe for me to swim to do some manual scrubbing on the algae? Maybe a hour at best?
2. Is it safe for the kids (teens) to swim? No telling how long they would be in there.
3. For my CH, which is at least partly to blame for the Algae IMO, I'm pondering options to remediate:
A. drain and refill with a filter on the hose.. (the ones for my RV didn't touch the CH in the water, so it would have be one designed for CH removal)
B. Hire a pool sanitation service that does the whole Reverse Osmosis on site thing.
C. Drain and have RO water brought in a truck to fill (not even sure if that is done around here)

 

[Texas Splash]

Let's call your CYA 40. It's safe for anyone to be in that water as long as you don't take the FC over 16.

As for the CH, I would leave it alone. You can keep the pH and TA lower to compensate until you get rains to help lower it. Or just get by until winter.

 

[frankos]

Let's call your CYA 40. It's safe for anyone to be in that water as long as you don't take the FC over 16.

As for the CH, I would leave it alone. You can keep the pH and TA lower to compensate until you get rains to help lower it. Or just get by until winter.

Awesome, thank you @Texas Splash is there a chart I'm missing or is it in Pool Math app, where it says what FC levels relative to the CYA are safe?

 

[mknauss]

CYA Chlorine Relationship - Further Reading

www.troublefreepool.com

 

[Newdude]

Anything between min and SLAM is sterile.
Alglea while unsightly, is harmless. You also need to be able to see the bottom well enough to rescue a disabled swimmer.

 

[frankos]

@mknauss Thank you. You know I'm such a stickler for precision and the CYA test leaves a lot to be desired. It just seems so subjective to me. I don't have the best eyes to begin with so I never know for sure the most accurate way to read the results. In the shade, in direct sunlight(which cauises a slight glare on the top of the water?)

Anyway, I just tested again and in direct sunlight and I'm low, like 20, like the tube was about full before I was confident I didn't see any resemblance of that black dot.

I'm adding now to bring it up to 40 and I'm going to switch to

Anything between min and SLAM is sterile.
Alglea while unsightly, is harmless. You also need to be able to see the bottom well enough to rescue a disabled swimmer.

View attachment 495843

View attachment 495844

So, I guess I'm worried about too much chlorine, rather than not enough to be sterile. Surely at some point the chlorine becomes toxic?

 

[mknauss]

How did your CYA drop to 20? That would have taken half of your pool water to be drained. Did you?

See CYA - Cyanuric Acid Test

 

[frankos]

No, Probably a bad reading on my part the first time. I was in a hurry that day. Today I was patient and took my time, making sure all measurements were accurate. Also, the pH was probably close to 9 the day of the first reading. Now sure how much that would effect things.

Regardless, I only had about 12oz of dry CYA. It's in there now. But I'll try to get to the store before it closes to get some more. I'll probably go with another 2 lbs and that should at least get me closer to 40 if my 2nd measurement was correct and 60 if it wasn't.

If you have advice on how to correctly look for the dot to disappear, I'm all ears. I know I can think it's gone, then change my position slightly and there it is... like lighting, glare on the water, whether I'm in sun or shade, time of day... so many variables. All of these seem to effect whether or not the dot is visible to me. I really don't know what the correct way to get consistent readings is.

 

[mknauss]

f you have advice on how to correctly look for the dot to disappear, I'm all ears.

When you do the CYA test, try this next time.

Once you have your solution ready, back to the sun, etc. Fill the vial to a line, say 80, lower the vial to your waist level and glance for the dot, you see it, add solution to the 70 line, glance, see it, repeat until you no longer see it with a glance. Then use the CYA value one step above the line you read. So if you stopped at 50, use 60 ppm CYA.

The vial is in logarithmic scale. So it is not viable to interpolate between the lines. Just use the whole numbers, such as 50, 40, 30, ....

 

[Newdude]

Surely at some point the chlorine becomes toxic?

Of course. Caustic, really, which in a way is toxic But you have no business with the FC over SLAM. So pretty much you can swim anytime, ever, so long as it's clear enough and not below minimum.

 

[frankos]

Okay I'm here for an update. I'm rather confident with my cya readings now and it goes cloudy / invisible about halfway between 55 and 60.

The chlorine level has been between 30 and 35 for 3 days now. Get these yellowish patches don't seem to want to go anywhere. I'm afraid to get the chlorine any higher because we have a party planned saturday. Yesterday I did a No-No and went to the LPS looking for some sort of algaecide. Their machines had a hard time testing my water correctly because the chlorine was so high. It said I had zero ta but that's just because the high chlorine the colors are off I know my ta is around 85. Anyway a customer suggested it could be iron spots and they all started to want to jump on that bandwagon. They said there's nothing I could do about it with the chlorine so high and then I would have to wait.

I came home and tried vitamin c on a stain to see if I could get it to go away it made minimal difference. I then put a 50/50 muriatic acid / water solution in a squirt bottle and try to squirting it directly on the stain. Still not much of a change.

If the stains were on the floor I know I can just put some shock on it and see if that takes care of it. But they're all on the walls. So I took a 3 inch tablet and started scrubbing on the walls. Lo and behold that is clearing it up! Just to double check my theory I put about a third of a bag of shock in a sock and rested it on a patch that's right on a curve in the deep end. I'll attach the photo but you can clearly see that there is a nice round spot where the sock was sitting. So whatever this stuff is it's definitely organic and it's definitely stubborn. I used that one 3 inch tab and got most of the visible spots out of the shallow end.

Yesterday I cleaned my filters let it run for a few hours and then started draining the pool and I've now got about 2 ft out of it. This is largely because A, the chlorine is so high and is not dropping quickly at all at this point and B my calcium hardness is well over 600. The lower water level should make it easier for me to finish scrubbing the deep end with another 3-in tab or two. I know that will continue to increase my overall chlorine and CYA, but I'll get it diluted back out when I start adding water tonight.

Once water got down below the tanning lid there were some slight algae spots that I could see. They look more tan than yellow or green, but I sprayed a diluted bleach on them and they turned greenish yellowish when wet.


I am concerned about little spots like the ones on the tanning ledge returning and giving me lots of problems once I feel the pull back up and the chlorine level comes down to normal. I'm considered using yellow out. I got some copper from The pool store too. It is Biogiard Banish. The instructions say to get the chlorine quite high before adding I'm tempted to dump it in but would like someone else who's been through this to let me know that I'm not going to cause more problems than solve?

 

[Donldson]

let me know that I'm not going to cause more problems than solve?

Sorry to tell you, but keeping your FC above SLAM is going to cause more problems than it solves, and everything you are contemplating doing is going to cause WAY more problems and likely won't even solve this one.

EDIT: Is your PoolMath log correct, did you really raise your FC to 63.5???

 

[frankos]

Sorry to tell you, but keeping your FC above SLAM is going to cause more problems than it solves, and everything you are contemplating doing is going to cause WAY more problems and likely won't even solve this one.

EDIT: Is your PoolMath log correct, did you really raise your FC to 63.5???

Lol, no. 67 drops, 33.5 ppm. Oops. I just swam around and scrubbed the walls with another tab. It seems like some of the worst areas that I thought I had conquered were starting to grow back.

Pool stores in my phosphates weren't that bad, but they had them up at like 28 PPM not ppb. To me that seems probably pretty high? I do have drop tests coming but they won't be here for a couple more days. I do have some phosphate remover arriving today.

I really feel like I'm grasping at straws here but I just need to have a reasonably clean and clear pool with chemistry that's not going to mess up people's hair or burn their eyes Saturday. I can do whatever I need to after that to finally take care of this problem.

 

[Mdragger88]

Okay I'm here for an update. I'm rather confident with my cya readings now and it goes cloudy / invisible about halfway between 55 and 60.

The chlorine level has been between 30 and 35 for 3 days now. Get these yellowish patches don't seem to want to go anywhere. I'm afraid to get the chlorine any higher because we have a party planned saturday. Yesterday I did a No-No and went to the LPS looking for some sort of algaecide. Their machines had a hard time testing my water correctly because the chlorine was so high. It said I had zero ta but that's just because the high chlorine the colors are off I know my ta is around 85. Anyway a customer suggested it could be iron spots and they all started to want to jump on that bandwagon. They said there's nothing I could do about it with the chlorine so high and then I would have to wait.

I came home and tried vitamin c on a stain to see if I could get it to go away it made minimal difference. I didn't put a 50/50 in your attic acid / water solution in a squirt bottle and try to squirting it directly on the stain. Still not much of a change.

If the stains were on the floor I know I can just put some shock on it and see if that takes care of it. But they're all on the walls. So I took a 3 inch tablet and started scrubbing on the walls. Lo and behold that is clearing it up! Just to double check my theory I put about a third of a bag of shock in a sock and rested it on a patch that's right on a curve in the deep end. I'll attach the photo but you can clearly see that there is a nice round spot where the sock was sitting. So whatever this stuff is it's definitely organic and it's definitely stubborn. I used that one 3 inch tab and got most of the visible spots out of the shallow end.

Yesterday I cleaned my filters let it run for a few hours and then started draining the pool and I've now got about 2 ft out of it. This is largely because A, the chlorine is so high and is not dropping quickly at all at this point and B my calcium hardness is well over 600. The lower water level should make it easier for me to finish scrubbing the deep end with another 3-in tab or two. I know that will continue to increase my overall chlorine and CYA, but I'll get it diluted back out when I start adding water tonight.

Once water got down below the tanning lid there were some slight algae spots that I could see. They look more tan than yellow or green, but I sprayed a diluted bleach on them and they turned greenish yellowish when wet.


I am concerned about little spots like the ones on the tanning ledge returning and giving me lots of problems once I feel the pull back up and the chlorine level comes down to normal. I'm considered using yellow out. I got some copper from The pool store too. It is Biogiard Banish. The instructions say to get the chlorine quite high before adding I'm tempted to dump it in but would like someone else who's been through this to let me know that I'm not going to cause more problems than solve?

Adding copper & yellow out will only make your problems worse! Do not use those. You will end up with a bromine pool & copper stains + still have an algae problem!
Scrub the pool, stick with the
SLAM Process- then follow the MA protocol after completing regular slam

Mustard Algae

Today We are going to show you how you can get rid of mustard algae in your pool. By following the steps in this guide and with no expensive chemicals.

www.troublefreepool.com

 

[HermanTX]

The chlorine level has been between 30 and 35 for 3 days now.

If your CYA is 60 then you should not be swimming until the FC drops below 24ppm and you are able to see the bottom of the pool.

 

[Mdragger88]

I do have some phosphate remover arriving today.

That will likely make your pool very cloudy

I really feel like I'm grasping at straws here but I just need to have a reasonably clean and clear pool with chemistry that's not going to mess up people's hair or burn their eyes Saturday. I can do whatever I need to after that to finally take care of this problem.

You are grasping at straws- all the straws you mentioned have the strong possibility of making things worse not better.
Stick with slam level fc which is 24ppm - no higher until you pass ALL 3 end of slam criteria. Scrub the whole pool daily to break up the biofilms that algae is protecting itself with so the chlorine can do it’s job.
It is safe to swim with fc up to slam level so long as you can see the bottom of the pool. Pause slam when your guests arrive.
When your guests leave resume slam. If you pass all 3 end of slam criteria on Saturday morning wait until after they leave to go for the MA protocol.

 

[clambert1273]

in your attic acid / water solution

This is possibly my favorite typo ever

 

[frankos]

I passed steps 1 and 2 of SLAM a week ago. Geting rid of visible algae seems impossible! I've been brushing 2 or 3 times a day for days!!! I alternate between a SS brush and my pool whale brush which is much easier for the sides in the deep. But some of this algae just doesn't want to give up. The only thing that is making a significant difference lately is scrubbing with a chlorine tab. Easy in the shallows, but not so much in the deep.

I increased the Algae to over 30ppm because the stuff on the walls is so stubborn.

The pool is crystal clear in the day, seeing the bottom is not a problem. There is however quite a bit of stuff floating in the pool. You can see it at night when the lights are on. I'll attach a photo. I've cleaned the filters twice now and was thinking of doing a mild acid bath for them next cleaning.

So here is the plan and I'll do my best to stick too it assuming no one here says it's wrong.

• I'll stop draining the pool and start refilling in a couple hours. I think I've removed a good 20-30% at this point.
• I'm refilling with CH filters on the hoses which would put in about 80ppm CH water.
• I will keep pool balanced aming for:
  • FC: SLAM Levels based on CYA
  • PH 7.4-7.8
  • CYA: 30-50
  • TA: around 70-80
  • CH: it is what it is, hopefully under 400.
  • SALT: 3400-3600
  • BOR: 30-50
• Keep Brushing at least once a day. I'll get in and brush by hand with tabs when I can.
• YM Protocol after SLAM is complete.
• I have my underwater camera charging too so I can get better photos / video to show what I'm experiencing.

Is there any reason to try and understand the levels of phosphates, nitrates in the pool? I don't understand how this algae isn't dying with repetitive brushings and such high chlorine content?

Big patches in deep end

Closeup of a tiny spot in shallow.
This is a bit smaller than a dime.

 

[frankos]

Here's a couple more photos.

The first one is the worst spot in the pool it's a different angle of the patch that is on the top of the photo in the previous post.


This next photo is of the step in the deep end. This step is about 20 in below the water line and goes down to the bottom of the pool. The pool is 9 ft deep but at this spot is closer to seven and a half or eight.

 

[Mdragger88]

You say you passed the oclt & cc criteria a week ago. Your logs are only go back 11 days & in that time you only reached slam level a couple times (with the exception of your recent over chlorination) & each time immediately after, you added dichlor which then immediately results in an inadequate fc level due to the increase in cya.
Treating phosphates & nitrates now won’t rid you of your algae problem. Adamantly maintaining slam level will.

Phosphate Removers - Further Reading

www.google.com

Also- when fc is above 10ppm the ph test is invalid
Focus on fc & cc testing only now that you’ve nailed down your cya level & it’s no longer a moving target.