New to TFP...Help with first SLAM. Chlorine expired?

[jschoen1]

Hi everyone! Newbie to TFP and attempting my first SLAM for algae.

Water test before SLAM:
FC= .5
CC = .5
TC = 1
CYA = 40
Target SLAM FC = 16

Using poolmath, we added 3.6 gallons of liquid chlorine. I checked the levels this morning and FC is only at 2. I am wondering if our chlorine was bad. It's HDX (home depot) brand liquid chlorine, 10%. According to the manufacturer code it was manufactured April 2020...but my husband said it was stored outside when he bought it, and we live in AZ where temps are over 110 most days in the summer.

I'm thinking we should return the rest and buy some different bleach? Is there anything else it could be besides this?

Kind of bummed out that our first SLAM attempt is already off the rails.

 

[Texas Splash]

Welcome to TFP! Same here in my area, HD stores their HDX out back in the pool section. It may have lost a little strength, but you should see an increase in FC. How are you testing? can you update your signature with all of your pool and equipment details to include the test kit? See mine as an example. Maybe we can compare poolmath notes. You might also post a pic or your water so we can see how cloudy or green it is.

 

[AndyTN]

First off, please include details in your signature about your pool to enable people to get better context. How bad is your algae? Just some spots on the floor or a full swamp? A picture would help.

The moment the bleach leaves the factory, it starts to degrade ever so slightly. The heat will not help preserve it but it isn't like the bleach is 2 years old. Your results of not raising the FC much is more likely due to the contaminates in the pool than the degraded bleach. I use the HDX bleach and have not had problems with it. If your 10% bleach is now 7-8%, it will be much better to use than to wait a few more days trying to find fresh bleach.

 

[Oly]

Test your FC after 30 minutes of adding the bleach and running your pump to confirm. FC will drop due to high algae levels over time and you need to add more bleach.

 

[epro05]

Breakdown of Bleach Over Time by Storage Temp - Further Reading

www.troublefreepool.com

4+ months at 110F. Check linked charts. I looked at degradation on the 8.25% chart and applied degradation %age to 10%. I think your bleach is less than 4%

 

[epro05]

Did you check pH before starting SLAM and adjust if needed?

 

[jschoen1]

Welcome to TFP! Same here in my area, HD stores their HDX out back in the pool section. It may have lost a little strength, but you should see an increase in FC. How are you testing? can you update your signature with all of your pool and equipment details to include the test kit? See mine as an example. Maybe we can compare poolmath notes. You might also post a pic or your water so we can see how cloudy or green it is.

Thanks so much for your reply. I updated my signature at your recommendation! Using the TF-100 kit. Attached are a couple pics. The water is actually very clear but there is visible green algae growth on the shallow areas that get a lot of afternoon sun (steps and shelf). We added the chlorine around midnight last night and I re tested this morning at 7am, FC had increased to 2 from .5 and CC had increased to 1 from .5, but I guess I was expecting a lot more since according to poolmath that volume of chlorine should have gotten us up to 16ppm to SLAM?

I'm trying to upload a pic but it keeps telling me the file is too large? Might be a mobile issue.

 

[jschoen1]

Did you check pH before starting SLAM and adjust if needed?

Yes we did! It was originally too high but we adjusted to 7.5 the day before starting the SLAM.

 

[epro05]

Your signature is still not showing.

 

[Texas Splash]

Also make sure you are doing the FC math correctly .... just to be safe..

10 ML water sample size. Add one generous scoop of powder and begin mixing (should be pink at first). Add drops until clear. Take number of drops and divide in half. Example: 20 drops equals and FC of 10.

 

[jschoen1]

First off, please include details in your signature about your pool to enable people to get better context. How bad is your algae? Just some spots on the floor or a full swamp? A picture would help.

The moment the bleach leaves the factory, it starts to degrade ever so slightly. The heat will not help preserve it but it isn't like the bleach is 2 years old. Your results of not raising the FC much is more likely due to the contaminates in the pool than the degraded bleach. I use the HDX bleach and have not had problems with it. If your 10% bleach is now 7-8%, it will be much better to use than to wait a few more days trying to find fresh bleach.

Test your FC after 30 minutes of adding the bleach and running your pump to confirm. FC will drop due to high algae levels over time and you need to add more bleach.

Thank you for the tip. Will try adding more and testing more promptly. We added the 3.6 gal last night at midnight and tested at about 7am this morning. I didn't realize you have to test so fast but that is helpful info to know. Do you think it is feasible that the chlorine could have dropped SO much in only 7 hours? Knowing that volume should have raised us to around 16ppm and we were only at 2? That seems like a pretty drastic difference. See my note and pics below, we are definitely not talking swamp status either.

Here's a couple pics - the water is clear but there is visible green algae growth on the shallow areas that get a lot of afternoon sun (steps, shelf).

 

[jschoen1]

Your signature is still not showing.

Sorry about that. Should be fixed now! Thank you for letting me know.

 

[jschoen1]

Also make sure you are doing the FC math correctly .... just to be safe..

10 ML water sample size. Add one generous scoop of powder and begin mixing (should be pink at first). Add drops until clear. Take number of drops and divide in half. Example: 20 drops equals and FC of 10.

Thank you - yes that's exactly how I was doing it. It only took 4 drops to get clear so FC = 2.
Here are a couple of pics attached (my signature is now updated too). My water is clear, there's just algae growth along the shallow areas that get a lot of afternoon sun (steps & shelf). Chlorine was added at midnight and I tested the water at 7am. It seems crazy to think that FC would have dropped from the estimated SLAM level I was hoping to achieve of approximately 16 after adding 3.6 gallons of liquid chlorine, down to only 2 within only 7 hours....do you think that's feasible or is my chlorine more likely just total bunk?

I saw another poster recommend to test within 30 minutes of adding the chlorine, so I'll try adding more and re-testing soon. That will probably be a more accurate determination of whether the chlorine is totally bad.

 

[mknauss]

Do you think it is feasible that the chlorine could have dropped SO much in only 7 hours?

Yes. With algae consuming it, the FC can drop fast. When possible, test and add liquid chlorine every few hours.