Combined Chlorine and Algae

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W

waldorfw

New member
May 6, 2024
3
Ohio
Pool Size
30000
Surface
Vinyl
Chlorine
Liquid Chlorine
Every year I encounter the same problem with my 30,000 gal pool (sand filter). After initial shock treatment to address green water, CC skyrockets and requires massive intervention to fix.

Last year, I tried to address the green pool water by first adding 6 lbs of Cal-hypo, which raised the CC to 6.8. Per pool store direction, I replaced half of the pool water, which reduced CC from 6.8 to 3.6 and then added 14 lbs of dichlor on day 1, 2 lbs on day 2, 2 lbs on day 3, to get CC to 0.8 (TC 1.1, FC 0.3) and CYA to 103. A few days later added 6 lbs of Cal-hypo and CC was 0.5 (TC 0.8, FC 0.3). The rest of the summer was manageable. In reading through this forum, it appears that I never got the FC to needed levels.

This year, initial readings of green pool were TC 1.3, FC 1.3, CYA 2. Pool store recomended 10 lbs of sodium dichlor and 1 pint of Banish (copper 3.3%). This resulted in CC of 4.3 (TC 4.8, FC 0.5), CYA 25. Now, they are recommending 60 gallons of chlorine or replace 1/2 of the water and then reshock. Seeking alternatives, I took a sample to another pool store, which recommended 3 lbs of non-chlorine shock, which reduced CC somewhat to 2.96 (TC 3.45, FC 0.49), but the pool is still green (because non-chlorine shock does not affect algae, I understand). I know I need to superchlorinate, but I am afraid to increase CC by putting too little shock, but 60 gallons?????

Please help.
 
Much smarter people will weigh in shortly, but you need to get away from the pool store and get your own test kit. You cannot mix the advice here with the advice from a pool store. They got you into this, but you and a great test kit and the really smart people here can get you out. You may have to drain a bunch of water - we need you to test for CYA yourself - but this will be the last drain and refill you will most likely ever do.

Do you have a reason why they suggested adding the Banish? That has copper and can end up being another issue to overcome.

Lastly, before the experts arrive..... Can you fill out a signature with your pool details?
 
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There is nothing you need to do about the CCs, they are just part of the cycle. FC gets used up and turned into CC, then the CC's are burned off by the sun. Unless you have an indoor pool or a cover, just let the sun do its job. Thats bad advice from the pool store.

Speaking of bad advice from a pool store, don't add 60 gallons of chlorine to your pool. That will raise your chlorine to a whopping 200 which is well above where you want it.

See why we don't like pool stores? Their testing is as bad as their advice.

I would suggest reading up on TFP and making sure this is right for you, then getting a proper test kit so you can know your true water readings and never have to step foot in a pool store ever again. Start with this article:
www.troublefreepool.com

ABC's of Pool Water Chemistry

There are several items things every pool owner should know about swimming pool water. We share details on the basics of Pool Water Chemistry.
www.troublefreepool.com www.troublefreepool.com
 
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You dumped a whole lot of copper into the pool that needs to be removed immediately. A very bad decision, plan to completely replace your pool water.

You need a proper test kit and the SLAM process (impossible without your own test kit). Without your own test results, we cannot help reliably.
Test Kits Compared
SLAM Process

CC is resolved by sanitary water and time under UV (the sun).
 
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Ok, I added information to my signature.
I should also mention that I added stain and scale defender and copper reading is now zero.
I am reluctant to get a test kit because I am red/green color blind.
Th Banish was intended to kill the algae.

So, per SLAM method, I should add 4 gal of chlorine to take FC from 0 to 11, given CYA is at 25. Next, keep adding chlorine up to 2-3 tmes per day to keep FC at 11, until OCLT<1.0, CC <0.5, and algae is gone. Is this correct?
 
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Without a FAS-DPD chlorine test ability, SLAM is not really possible.
With FAS-DPD, you judge completion by absence of color, which should be possible for you.

CYA at 25 is not possible - the scale is logarithmic, so it's either 20 or 30. But if that's pool store testing, it may actually be 50.
CYA testing does not require seeing color change.

A properly calibrated pH meter could handle that for you, and the color change on TA testing is likely contrast'y enough to ascertain.
With a vinyl pool CH is not something you measure often, unless you continue to dump in DiChlor which can lead to waterline scaling.
 
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Get a kit on order today - taylor k2006c or tf100/pro are the only ones that have all the tests you need
(this will cost less than 1 trip to the pool store)
Until your kit comes you can add 5ppm worth of liquid chlorine to the pool each day to prevent things from getting worse until you can properly do battle with accurate data.
Use PoolMath to calculate amounts.
In the meantime scoop & vac as well to remove as much organic debris as possible.
& Read up on
Pool Care Basics &
SLAM Process

*The sequestrant did not remove your copper - it only hid it & it will wear off so you will eventually either need to replace your copper laden water with copper free water or use regular doses of Sequestrant to keep it hidden & prevent staining, green hair/fingernails etc.
 
waldorfw said:
I am reluctant to get a test kit because I am red/green color blind.
Click to expand...
The TA test is Green -> Red, but that's not really that critical day-to-day.
PH test is shades of red, although there are PH meters which can make that easier.
CH test is Red->Blue
FAS/DPD (Free Chlorine) is Pink-> Clear - this is important one - you can see the test here as an example (skip to about 1:45 to see the actual change)
CYA test is Clear->Milky->Opaque
 
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