Green cloudy pool - help with TF-100 readings

[dawydiuk]

Hi All,

I have a ~14k gallon pebble tech pool in AZ(hot). I have two mesquite trees in my backyard meaning frequently dropping leaves and pollen/flowers in the pool. Pool is about 25 years old, purchased home 4 years ago.

My pool guys struggled to keep my water clear, he wanted to drain and acid wash it, and quit when I didn't want to move forward. I've been using test strips and adding chlorine as needed based on test strip data for the past year or so. Results are the same as the pool guy... I brush about every 3 days and when I do you can see the green algae coming off the walls and where the vacuum misses, if I wait for a week to brush my pool after I brush my pool is totally green and I can't see the bottom. I've went to the pool store, and they said my biggest problem is total dissolved solids and I need to drain my pool(drain half way fill, and retest chemicals), they said I'm wasting my money adding chemicals until I do...

I picked up a TF-100 kit and just did my first test and my levels seem way off to the point of after adding 70-80 drops and the color not changing I just stopped.... I was very careful with all my measurements and rinsed everything before taking any readings. Please note I added chlorine pucks this morning in case that has any impact. Below are my readings per my test strips and the TF-100. I would really really appreciate any help, as I was excited to get the kit but really disappointed my levels seem so far off I'm wasting the testing chemicals and not even getting to a known level...

Test strips:
Hardness: 350
Total Chlorine: 25
Free Chlorine: 15
Bromine: 0
CYA: 0
pH: 10

TF-100:
Calcium: stopped at 71 drops, > 1,175
Free Chlorine: 38 ppm
Alkalinity: stopped at 80 drops, >700
CYA: Unmeasureable, I was well below any of the measurements and it's not linear so can't estimate. >100
Combined Chloramines: None

 

[IceShadow]

Do a diluted CYA test. Take the sample, then mix the mixed sample 1:1 with just pool water, and do the CYA test again. Multiply result by 2.

 

[clambert1273]

In AZ your results aren't surprising. When we bought this house in 2020 the owners had mangled the pool water. I tried to do RO on it but it was too bad so our first week in our house I drained it completely and shoveled gunk out. Filled it back up & ran that first year then in 2021 we had it renovated and it is much better now but I am pretty sure next spring I'm gonna have to drain at least half.

 

[mknauss]

Time for a complete drain and refill. See Draining - Further Reading

 

[Bperry]

Hi All,

I have a ~14k gallon pebble tech pool in AZ(hot). I have two mesquite trees in my backyard meaning frequently dropping leaves and pollen/flowers in the pool. Pool is about 25 years old, purchased home 4 years ago.

My pool guys struggled to keep my water clear, he wanted to drain and acid wash it, and quit when I didn't want to move forward. I've been using test strips and adding chlorine as needed based on test strip data for the past year or so. Results are the same as the pool guy... I brush about every 3 days and when I do you can see the green algae coming off the walls and where the vacuum misses, if I wait for a week to brush my pool after I brush my pool is totally green and I can't see the bottom. I've went to the pool store, and they said my biggest problem is total dissolved solids and I need to drain my pool(drain half way fill, and retest chemicals), they said I'm wasting my money adding chemicals until I do...

I picked up a TF-100 kit and just did my first test and my levels seem way off to the point of after adding 70-80 drops and the color not changing I just stopped.... I was very careful with all my measurements and rinsed everything before taking any readings. Please note I added chlorine pucks this morning in case that has any impact. Below are my readings per my test strips and the TF-100. I would really really appreciate any help, as I was excited to get the kit but really disappointed my levels seem so far off I'm wasting the testing chemicals and not even getting to a known level...

Test strips:
Hardness: 350
Total Chlorine: 25
Free Chlorine: 15
Bromine: 0
CYA: 0
pH: 10

TF-100:
Calcium: stopped at 71 drops, > 1,175
Free Chlorine: 38 ppm
Alkalinity: stopped at 80 drops, >700
CYA: Unmeasureable, I was well below any of the measurements and it's not linear so can't estimate. >100
Combined Chloramines: None

Just to be sure, try describing how you are doing the free chlorine and the CYA test and we can help you confirm you didn’t miss something. Those are so far off that it would be wise to make sure the test procedure is correct as a double check.

 

[dawydiuk]

Just to be sure, try describing how you are doing the free chlorine and the CYA test and we can help you confirm you didn’t miss something. Those are so far off that it would be wise to make sure the test procedure is correct as a double check.

I stopped at 71 drops on calcium test as the water didn't change to blue. I stopped at 80 drops on the Alkalinity test as the color was pink but not yet red. Im taking a sample to pool store as a sanity check to see what they say calcium and alkalinity levels are. It sounds like draining pool is likely needed?

 

[clambert1273]

I stopped at 71 drops on calcium test as the water didn't change to blue. I stopped at 80 drops on the Alkalinity test as the color was pink but not yet red. Im taking a sample to pool store as a sanity check to see what they say calcium and alkalinity levels are. It sounds like draining pool is likely needed?

View attachment 489373View attachment 489374

I think with these don't necessarily take color term at face value. Red could be any shade of pink. The important piece is the color change & when it stops changing color (I usually have an extra drop to make sure it doesn't change any more then subtract my extra drop checks).

 

[Mdragger88]

It sounds like draining pool is likely needed?

Yes, unfortunately.
The question is after the water exchange how will you maintain the pool going forward to mitigate these issues…

How to Chlorinate Your Pool

Before chlorinating your pool, you should know these simple tips. Learn the best way to add chlorine to your pool.

www.google.com

Calcium Hardness - Further Reading

www.troublefreepool.com

 

[Bperry]

I stopped at 71 drops on calcium test as the water didn't change to blue. I stopped at 80 drops on the Alkalinity test as the color was pink but not yet red. Im taking a sample to pool store as a sanity check to see what they say calcium and alkalinity levels are. It sounds like draining pool is likely needed?

View attachment 489373View attachment 489374

The TA test should give you a note about testing higher than expected levels like that calcium test. Did you try following those? Sadly the pool store is even worse about water tests so I would’NT trust anything they tell you, except for maybe their metals test. For sure not to buy anything from them.

If these test results are accurate, then yea it’s probably cheaper to drain and refill. But you have to figure out how you plan to avoid this from happening again like mentioned above.

 

[Bperry]

The TA test should give you a note about testing higher than expected levels like that calcium test. Did you try following those? Sadly the pool store is even worse about water tests so I would trust anything they tell you, except for maybe their metals test. For sure not to buy anything from them.

If these test results are accurate, then yea it’s probably cheaper to drain and refill. But you have to figure out how you plan to avoid this from happening again like mentioned above.

And you’re double sure you filled it to the correct mark for each test? The chlorine test should only get filled to the 10ml mark and that allows you to use less reagent and easier math.

 

[IceShadow]

Your FC is very high. This will affect the colors of the test. Look for a shift, not necessarily a change to a specific color.

Did you do a diluted CYA test? If your CYA is too high, you’re gonna be exchanging water. But how high is it? The diluted test should at least give you an idea.

 

[Bperry]

Your FC is very high. This will affect the colors of the test. Look for a shift, not necessarily a change to a specific color.

Did you do a diluted CYA test? If your CYA is too high, you’re gonna be exchanging water. But how high is it? The diluted test should at least give you an idea.

This is probably your best course of action. If your CYA is sky high you’ll need to dump the water anyway so doesn’t matter what all the other levels are.

 

[dawydiuk]

And you’re double sure you filled it to the correct mark for each test? The chlorine test should only get filled to the 10ml mark and that allows you to use less reagent and easier math.

Yes

 

[clambert1273]

Like I said in AZ it isn't surprising. When I first moved in, I couldn't even test the water it was so bad. The day we got here, the previous owners left like 20 pucks laying on the bottom of the pool I knew I was in trouble. RO wouldn't work and we just dumped it all. Before my HOA started getting huffy about people draining. It was the best & easiest decision so I could start with a blank slate. We emptied it on one day & filled it the next and I only had one water hose then. Once full, I got to balance it my way & not worry about what they did. The damage from them was obvious before & during reno. You can do it I promise

 

[dawydiuk]

Your FC is very high. This will affect the colors of the test. Look for a shift, not necessarily a change to a specific color.

Did you do a diluted CYA test? If your CYA is too high, you’re gonna be exchanging water. But how high is it? The diluted test should at least give you an idea.

I did a diluted CYA test, it didn't say to measure but I did to try to ensure accuracy. It was 15 ml to the bottom of the label, so I added 7.5ml of tap water and 7.5 ml of pool water. I couldn't see the black dot and I wasn't at the 100 level so my CYA is > 200... Oddly the pool store and my strips both indicated no CYA.

It's going to be high of 75 on Wed, so plan to start draining Tuesday night. I don't have any stains so plan to fill it up right away, unless there is anything else I should do when it's empty?

I use IN THE SWIM - 3 INCH CHLORINE TABLETS - 50 LBS I believe they contain CYA("sun-stabilized") and so I believe this will lead to the same problem again(CYA levels to high). As far as I know most all chlorine tables contain CYA, does this mean I need to switch to liquid chlorine or I'm bound to have these same problems again?

Going forward I plan to use the TF-100 test kit to ensure my chemicals(Calcium, Free Chlorine, Alkalinity, CYA, & Combined Chloramines) are balanced. Is that sufficient or should I be measuring other chemicals(eg the pool store said my phosphates could be problematic given I have to trees next to the pool)?

 

[clambert1273]

I did a diluted CYA test, it didn't say to measure but I did to try to ensure accuracy. It was 15 ml to the bottom of the label, so I added 7.5ml of tap water and 7.5 ml of pool water. I couldn't see the black dot and I wasn't at the 100 level so my CYA is > 200... Oddly the pool store and my strips both indicated no CYA.

It's going to be high of 75 on Wed, so plan to start draining Tuesday night. I don't have any stains so plan to fill it up right away, unless there is anything else I should do when it's empty?

I use IN THE SWIM - 3 INCH CHLORINE TABLETS - 50 LBS I believe they contain CYA("sun-stabilized") and so I believe this will lead to the same problem again(CYA levels to high). As far as I know most all chlorine tables contain CYA, does this mean I need to switch to liquid chlorine or I'm bound to have these same problems again?

Going forward I plan to use the TF-100 test kit to ensure my chemicals(Calcium, Free Chlorine, Alkalinity, CYA, & Combined Chloramines) are balanced. Is that sufficient or should I be measuring other chemicals(eg the pool store said my phosphates could be problematic given I have to trees next to the pool)?

No worries on the phosphates bit. I have 2 huge trees next to my pool and all the neighborhood leaves as well lol as long as everything is balanced phosphates are a moot point.

 

[Bperry]

I did a diluted CYA test, it didn't say to measure but I did to try to ensure accuracy. It was 15 ml to the bottom of the label, so I added 7.5ml of tap water and 7.5 ml of pool water. I couldn't see the black dot and I wasn't at the 100 level so my CYA is > 200... Oddly the pool store and my strips both indicated no CYA.

It's going to be high of 75 on Wed, so plan to start draining Tuesday night. I don't have any stains so plan to fill it up right away, unless there is anything else I should do when it's empty?

I use IN THE SWIM - 3 INCH CHLORINE TABLETS - 50 LBS I believe they contain CYA("sun-stabilized") and so I believe this will lead to the same problem again(CYA levels to high). As far as I know most all chlorine tables contain CYA, does this mean I need to switch to liquid chlorine or I'm bound to have these same problems again?

Going forward I plan to use the TF-100 test kit to ensure my chemicals(Calcium, Free Chlorine, Alkalinity, CYA, & Combined Chloramines) are balanced. Is that sufficient or should I be measuring other chemicals(eg the pool store said my phosphates could be problematic given I have to trees next to the pool)?

All chlorine in tablet or powdered form contains stuff that builds up over time and makes you have to drain. The only other alternatives are liquid chlorine or a salt water chlorinator. I’d skip the liquid and go straight for the SWCG. It pays for itself over the long term and is just easier to maintain.

 

[Mdragger88]

I did a diluted CYA test, it didn't say to measure but I did to try to ensure accuracy. It was 15 ml to the bottom of the label, so I added 7.5ml of tap water and 7.5 ml of pool water. I couldn't see the black dot and I wasn't at the 100 level so my CYA is > 200... Oddly the pool store and my strips both indicated no CYA.

Not surprising- the cya test is the one that the pool stores get wrong more than right, also the strips are easily bleached out leading to such a result.

It's going to be high of 75 on Wed, so plan to start draining Tuesday night. I don't have any stains so plan to fill it up right away, unless there is anything else I should do when it's empty?

If you have anywhere algae can hide it’s a convenient time to check & scrub those places especially since you have been underchlorinating for some time.
Light niches, ladders, drain covers etc.

I use IN THE SWIM - 3 INCH CHLORINE TABLETS - 50 LBS I believe they contain CYA("sun-stabilized") and so I believe this will lead to the same problem again(CYA levels to high). As far as I know most all chlorine tables contain CYA, does this mean I need to switch to liquid chlorine or I'm bound to have these same problems again?

Correct- liquid chlorine or a salt water chlorine generator is the best way to accomplish daily chlorination without adverse side effects as they only add fc - nothing more.
All other forms of chlorine add either cya or calcium which only leaves the water through replacement. Get your cya in check & save the tabs for vacation or when you need a little bump in cya.
Here’s how each dissolved tab affects your water- you can see how that can get out of hand quickly

Going forward I plan to use the TF-100 test kit to ensure my chemicals(Calcium, Free Chlorine, Alkalinity, CYA, & Combined Chloramines) are balanced. Is that sufficient or should I be measuring other chemicals(eg the pool store said my phosphates could be problematic given I have to trees next to the pool)?

If the proper fc/cya ratio is maintained
FC/CYA Levels
Phosphates are pretty irrelevant. I have trees all around my pool as do most here with outdoor pools, I have never tested my phosphate level or treated for them- having “algae food” doesn’t really matter if you don’t have a habitable environment for algae in the 1st place.
If you are still concerned with it & want to test for them etc. it’s last on the list of importance.
here is the way so you can STAY OUTTA THE POOL STORE

Phosphate Removers - Further Reading

www.google.com

One more thing…
Managing your ch -
Test your fill water’s ch, ta, & ph & record that somewhere so you can know how it will affect your pool each time you add water & get an idea of what your starting point will be on a fresh fill.
Do you have the ability to use softened water for top offs?
Doing so would greatly reduce the need for periodic drains due to high ch.
To prevent scaling managing csi is imperative- turn on csi tracking in
PoolMath

Calcium Saturation Index (CSI)

How is CSI calculated? Very simple – use our PoolMath tool. To ensure long plaster life and save money, click here to learn more.

www.troublefreepool.com

 

[IceShadow]

I did a diluted CYA test, it didn't say to measure but I did to try to ensure accuracy. It was 15 ml to the bottom of the label, so I added 7.5ml of tap water and 7.5 ml of pool water. I couldn't see the black dot and I wasn't at the 100 level so my CYA is > 200... Oddly the pool store and my strips both indicated no CYA.

It's going to be high of 75 on Wed, so plan to start draining Tuesday night. I don't have any stains so plan to fill it up right away, unless there is anything else I should do when it's empty?

I use IN THE SWIM - 3 INCH CHLORINE TABLETS - 50 LBS I believe they contain CYA("sun-stabilized") and so I believe this will lead to the same problem again(CYA levels to high). As far as I know most all chlorine tables contain CYA, does this mean I need to switch to liquid chlorine or I'm bound to have these same problems again?

Going forward I plan to use the TF-100 test kit to ensure my chemicals(Calcium, Free Chlorine, Alkalinity, CYA, & Combined Chloramines) are balanced. Is that sufficient or should I be measuring other chemicals(eg the pool store said my phosphates could be problematic given I have to trees next to the pool)?

The other three responses have you covered. Have you tried testing your fill water for CH, TA, pH to see what you're going to be starting from?

 

[dawydiuk]

Thanks everyone so much for all the help!!!!

Pool is draining now, I measured the fill water CH = 250 ppm & TA = 140 ppm. Below is a picture of pH, I'm guesstimating a little above 8.2?

Once the pool is drained I'll brush the green / algae from all surfaces, should I use liquid chlorine on the brush?

How many 3" chlorine tabs should I put in once full, and what other chemicals do I need? I'd love to learn how to figure this out myself so can do this on my own in the future with out needing to ask for help

Please note it's a 14k gallon pebble tech pool.