Need advice regarding my Green Swamp

Jan 30, 2017
11
Nashville, TN
Late this past fall I lost control of my pool and algae (dark green) took over. I let it go thinking over the winter the algae would die off. No such luck. Up to that point I have always used chlorine tabs in a autofeeder (different kinds/makes - never knew the difference) and run filter 24/7.

Since then I discovered this sight, ordered a TST test kit, and read about the SLAM process.
About a month ago, I tested and came up with the following levels:
PH: 7.2
FC: 26
CC: 0
TA: 160
CYA: 120+ (tested a number of times and lost sight of the black dot well below the 100 mark)

I then added baking soda and raised the PH to 8-8.2 thinking FC would start doing it's thing. Waited a few days, no change, tested again and all other levels were about the same. Going with the SLAM advice, I drained about half the pool (later when I got water bill I realized about 3K short of half.) I refilled, let it circulate for another day and tested again. No visable change in CYA..still lose sight of black dot well short of 100 - looked unchanged.

I tested again this morning and here are current results:
PH: 8-8.2
FC: 10-10.5
CC: 0
TA: 160
CYA: 120+ (same as described previously - not exactly sure how high it is)

I'm following posted directions here regarding testing, so I think it's fairly accurate. Hopefully I've shared enough to be helpful. Where do I go from here?
 

tim5055

Mod Squad
TFP Expert
LifeTime Supporter
May 11, 2014
10,122
Franklin, NC
Welcome to TFP!!:handwave:

First, stop adding baking soda - that raises TA, not pH.

Second, you don't need your pH higher, it's too high already. you need to add muratic acid (use Pool Math) to get the pH back down to 7.2

Third, 100 is the limit of the CYA test, so at this level we are unsure if it is 100 or some number above 100. Don't equate “just a little over 100” to a number, the tube is not marked for such extrapolation. At this point I would recommend at least a 50% water exchange again to get the CYA down to a number that can be tested. For vinyl lined pools leave at least one foot of water in the shallow end to keep from floating the liner and all pool owners are cautioned that in areas with a high water table lowering the water too much can “float” the pool out of the ground.

Forth, a little more reading about the SLAM. Start with ABCs of Water Chemistry and Turning Your Green Swamp Back into a Sparkling Oasis
 

YippeeSkippy

Mod Squad
LifeTime Supporter
Jan 17, 2012
9,417
Evans, Georgia
Hey there MusicCitySwimmer :handwave: Glad you found us as we can help you!

Which test kit did you order?

Have you read this--> ABCs of Pool Water Chemistry and this --> SLAM ??

Take *equal* amounts of pool water and tap water and mix, then use this sample to re-test your CYA but double the results. You still may be far over 100ppm on CYA and will have to drain again. All those pucks just stacked up and your pool is entirely saturated with excess CYA :( After the drain and refill and having your CYA at a manageable level-
Recheck you FC first as your pH may not be accurate if FC is over 10. Usually it inaccurately shows high pH though.

Then you need to stock up on liquid chlorine- either from a pool store source (usually 10-12% strength) or plain, unscented household bleach from Walmart (8.25%)

Commit to testing *often* at first and raising your FC level to the SLAM level and keeping it there as often as you can manage. Just follow the SLAM steps.


Holler back with any other questions!

Yippee :flower:
 
Jan 30, 2017
11
Nashville, TN
Appreciate it Yippee-

I have the TF test kit. I did try the CYA re-test method per the extended test kit directions link here....same result. I have also read the SLAM, which is what prompted my concern regarding my high CYA. I figured all that tab use may have been the culprit!

Understood regarding bleach supply..found Home Depot HDX 8.25% to be the cheapest in my area.
 
Jan 30, 2017
11
Nashville, TN
Appreciate it. I thought baking soda raised PH slightly, and I had it on hand. Didn't think about the impact on TA. Re-read the water chemistry link...it all ads up now. I read the Green Swamp article originally, which prompted my concern with the high CYA. Hate to drain again, but good to know that is the right thing to do.
 

YippeeSkippy

Mod Squad
LifeTime Supporter
Jan 17, 2012
9,417
Evans, Georgia
Appreciate it Yippee-

I have the TF test kit. I did try the CYA re-test method per the extended test kit directions link here....same result. I have also read the SLAM, which is what prompted my concern regarding my high CYA. I figured all that tab use may have been the culprit!

Understood regarding bleach supply..found Home Depot HDX 8.25% to be the cheapest in my area.
I caution you against buying bleach at Lowes or HomeDepot. They tend to store it outside in the garden center where heat/light weaken it enormously, not to mention they don't get a huge turn over in bleach this time of year so it very well may be old degraded stuff. Check the Julian date stamp on the jug.

...and yeah... you have another big drain in your future. :(
Yippee :flower:
 

domct203

Bronze Supporter
LifeTime Supporter
TFP Guide
Jun 3, 2015
3,959
CT
Are you doing the CYA test outdoors on a bright sunny day, with your back to the sun?

How much backing soda did you add?
 
Jan 30, 2017
11
Nashville, TN
Are you doing the CYA test outdoors on a bright sunny day, with your back to the sun?

How much backing soda did you add?

Yes, I've followed the extended test kit directions article in Pool School and tried it numerous times...I do think I've done the test correctly.

I added about 8 lbs of baking soda (per instructions on arm & hammer bag) about a month ago when my PH was around 7.2, which at the time I thought was low. I've since learned otherwise...
 

tim5055

Mod Squad
TFP Expert
LifeTime Supporter
May 11, 2014
10,122
Franklin, NC
I caution you against buying bleach at Lowes or HomeDepot. They tend to store it outside in the garden center where heat/light weaken it enormously, not to mention they don't get a huge turn over in bleach this time of year so it very well may be old degraded stuff. Check the Julian date stamp on the jug.
I can't agree with this more. Big box hardware stores are generally not a great place to get chlorine.

Appreciate it. I thought baking soda raised PH slightly, and I had it on hand. Didn't think about the impact on TA. Re-read the water chemistry link...it all ads up now. I read the Green Swamp article originally, which prompted my concern with the high CYA. Hate to drain again, but good to know that is the right thing to do.
YS explained about a diluted test above, here are more details:

100 is the limit of the CYA test, so you have to do a diluted test. While the full instructions are in the Pool School, here is the short version. Mix 50% pool water with 50% tap water. Use this mixed sample as your test water. If still at a 100 you will need to dilute more. Here is a great chart by JamesW to explain dilution rates and what you multiply the results by to get an approximation of your CYA level.

Pool water......Tap or distilled water.........Multiply result by

....1...................1................................2
....1...................2................................3
....1...................4................................5

But, with each additional level of dilution you get more error in the test.

Right now yo know you need to drain, may as well save the CYA test reagents and wait until you do a huge drain to test again.
 

madwil

Well-known member
May 2, 2011
370
lebanon tn
I'm also in Nashville. Try cleaning bleach at Walmart. 6%at 1.77 a gal
. Also nashville water will adjust your sewer bill for a one time event. Don't want to pay sewage for water in the street!
 
Jan 30, 2017
11
Nashville, TN
Late this past fall I lost control of my pool and algae (dark green) took over. I let it go thinking over the winter the algae would die off. No such luck. Up to that point I have always used chlorine tabs in a autofeeder (different kinds/makes - never knew the difference) and run filter 24/7.

Since then I discovered this sight, ordered a TST test kit, and read about the SLAM process.
About a month ago, I tested and came up with the following levels:
PH: 7.2
FC: 26
CC: 0
TA: 160
CYA: 120+ (tested a number of times and lost sight of the black dot well below the 100 mark)

I then added baking soda and raised the PH to 8-8.2 thinking FC would start doing it's thing. Waited a few days, no change, tested again and all other levels were about the same. Going with the SLAM advice, I drained about half the pool (later when I got water bill I realized about 3K short of half.) I refilled, let it circulate for another day and tested again. No visable change in CYA..still lose sight of black dot well short of 100 - looked unchanged.

I tested again this morning and here are current results:
PH: 8-8.2
FC: 10-10.5
CC: 0
TA: 160
CYA: 120+ (same as described previously - not exactly sure how high it is)

I'm following posted directions here regarding testing, so I think it's fairly accurate. Hopefully I've shared enough to be helpful. Where do I go from here?
Since my original post I drained well over half the pool - down to 1 foot in shallow end. This morning I retested and here are the results:
FC: 1
CC: 0
PH: 8.2
TA: 120
CYA: 130

I noticed the PH remained the same, the FC lowered significantly, and the TA lowered. I used the 50% mixed water version to test CYA because in the first test I lost sight of the black dot well below 100. Is it possible that after draining about 50% of the pool twice my CYA could still be that high? I read somewhere that during algea bloom CYA can be inflated?

I want to SLAM but confused by this CYA reading.

Wasn't sure how best to update post...hope this makes sense.
 

Mr Bruce

TFP Guide
Mar 24, 2014
2,095
Greenville, SC
It is certainly possible. You could have had CYA well the 3-400s. pH could have been higher than 8.2 too, since that is the top of the test.

Before draining again though, is the water is so murky it is messing with the CYA test? What do you get with just straight pool water for the CYA test?
 
Jan 30, 2017
11
Nashville, TN
The water sample doesn't necessarily look murky, though I notice after letting it sit for awhile algae settles to the bottom of the sample bottle. As I mentioned, with straight pool water I lose sight of the black dot well before reaching the 100 mark. That's why I'm asking if the test may be skewed by the algae in the water.
 

tim5055

Mod Squad
TFP Expert
LifeTime Supporter
May 11, 2014
10,122
Franklin, NC
The water sample doesn't necessarily look murky, though I notice after letting it sit for awhile algae settles to the bottom of the sample bottle. As I mentioned, with straight pool water I lose sight of the black dot well before reaching the 100 mark. That's why I'm asking if the test may be skewed by the algae in the water.
It is doubtful that algae in the water will mess up the test.

It is more likely that the pool had been fed a steady diet of tabs and granular shock, pushing the CYA into the hundreds.
 

Mr Bruce

TFP Guide
Mar 24, 2014
2,095
Greenville, SC
It is actually very possible, I've seen it first hand. Pool water so gunky it obscures the dot in the CYA tube around 40-50.

with straight pool water I lose sight of the black dot well before reaching the 100 mark
If the "stuff" settles after a while, I would collect a large sample in a pitcher or measuring cup and let it settle out. Then use a pipette to get enough of a clear sample from the top and do the CYA test with that.
 

tim5055

Mod Squad
TFP Expert
LifeTime Supporter
May 11, 2014
10,122
Franklin, NC
It is doubtful that algae in the water will mess up the test.

It is more likely that the pool had been fed a steady diet of tabs and granular shock, pushing the CYA into the hundreds.
I stand corrected and retract these comments-

I totaly mis-read what was said.
 
Jan 30, 2017
11
Nashville, TN
Since my original post I drained well over half the pool - down to 1 foot in shallow end. This morning I retested and here are the results:
FC: 1
CC: 0
PH: 8.2
TA: 120
CYA: 130

I noticed the PH remained the same, the FC lowered significantly, and the TA lowered. I used the 50% mixed water version to test CYA because in the first test I lost sight of the black dot well below 100. Is it possible that after draining about 50% of the pool twice my CYA could still be that high? I read somewhere that during algea bloom CYA can be inflated?

I want to SLAM but confused by this CYA reading.

Wasn't sure how best to update post...hope this makes sense.
Really confused folks. Since my last post I drained over half the pool for the 3rd time and the CYA did indeed drop to a manageable level this time. After testing several times to be sure, I came up with a CYA reading of 80. Also added some CA to bring my PH down to 7.2. Began SLAM today and added 8 - 128oz jugs of 8.25% chlorine per Pool Math to bring to shock level of 36. 30 minutes later I tested and FC was still 36...and I saw no signs of improvement. An hour later tested again and FC was still 36, the same 2 hours later.

Out of desperation I added another 4 jugs of chlorine a bit ago. Am I missing something??

Update: Now about 5 hours into it my FC is 50...due to the extra 4 jugs I added...but still no visable signs of green color lightening or algae being killed. Just flushed filter and there was some green for a bit, but not as much as I would have thought. Help!!
 

Mr Bruce

TFP Guide
Mar 24, 2014
2,095
Greenville, SC
:shock: It is really not a good idea to go that far above SLAM levels. SLAM for a CYA of 80 is 31.

This sounds like a filtration problem. Can you post a picture?

edit: Just noticed this is all today. SLAMs take several days, it's not a one time thing!
 
Jan 30, 2017
11
Nashville, TN
:shock: It is really not a good idea to go that far above SLAM levels. SLAM for a CYA of 80 is 31.

This sounds like a filtration problem. Can you post a picture?

edit: Just noticed this is all today. SLAMs take several days, it's not a one time thing!
I guess I was trying to be safe in case I was overzealous on my CYA test and assumed 90 in Pool Math...didn't think over chlorinating at first would be a bad thing.
I also assumed in following the "Turning Your Green Swamp" sticky that FC would immediately start dropping once it started killing algae, and you should test after 30 minutes and add more chlorine to bring FC back up to shock level. My FC has not dropped at all after hours..and does not appear to be killing algae.

And still I see no improvement in water color after about 4 hours??

My filtration seems to be working..when I flush it out it is dark green.
 
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