Why does the rain cause me to slam my pool

Frezel

Active member
Jul 6, 2018
40
Doylestown, PA
So it's been raining alot here however we get a few nice days and water chemistry is perfect. Then it rains for a day however it does not affect my levels that much. I mean my chlorine may go down a point at most but I am able to keep my chlorine levels at 3. My cya has been low like around 20. The water is still clear however there is allot of algae areas on the bottom and I try to vacuum but it still clouds the water and doesn't clear unless I slam it.
First off why is algae occurring if my chlorine levels are at 3?
Is my cya to low?
Should I be slamming my pool when I see this much algae at bottom of pool after vacuuming and doesn't clear with running pump?
Do you guys have any suggestions with chemistry or running pump longer during rain storms etc...
 

duraleigh

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Rain is almost irrelevant to pool maintenance.....unless you get a frog strangler!

All of our conversations begin and end with test results so we all get on the same page. Can you post current ones?
 

duraleigh

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Let's see, where to start?

1. Algae simply does not appear in a pool that is adequately chlorinated however that chlorine has to be maintained 24/7 at that adequate level.

2. So it would seem at some point your chlorination has gotten too low. To get your pool back to crystal clear (and eliminate ANY sign of algae), you must follow the SLAM process. It is a process and you must follow the article in Pool School precisely.

3, Before you start the SLAM I would add 20 ppm CYA to get your pool 30-40.....something you can test for a little better.

4. Start the SLAM and read every word of the article The SLAM process Your initial dose of chlorine should bring your FC to about 14 ppm.
The rest of your numbers are fine. Once you begin the SLAM, you only need to test for FC and CC.

Do you have a pic of your current pool water?
 

Frezel

Active member
Jul 6, 2018
40
Doylestown, PA
I do not have a pic but generally the presentation is water is clear and at the bottom there are allot of patches of algae as if the pool wasn't vacummed for a long time right after heavy rain, I try to vacuum it slowely and ends up in water column that just never clears. I did go ahead and shock it and will check levels tonight and again first thing in morning. What baffles me is that I never really let the chlorine drop below 3 usually hold between 3-5. So I don't see how this stupid algae always comes back. My slam process I follow to the T. It's always allot of rain my pool turns. I also keep my pool pumps on only 8 hours a day should I increase the time when I am not in a slam method??
 

tim5055

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May 11, 2014
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Franklin, NC
I do not have a pic but generally the presentation is water is clear and at the bottom there are allot of patches of algae as if the pool wasn't vacummed for a long time right after heavy rain, I try to vacuum it slowely and ends up in water column that just never clears. I did go ahead and shock it and will check levels tonight and again first thing in morning. What baffles me is that I never really let the chlorine drop below 3 usually hold between 3-5. So I don't see how this stupid algae always comes back. My slam process I follow to the T. It's always allot of rain my pool turns. I also keep my pool pumps on only 8 hours a day should I increase the time when I am not in a slam method??
Pump run time has little effect on the proper chlorination of a pool unless the time is needed for a SWCG to generate adequate chlorine.

You say you have SLAMed your pool. Have you followed the directions from beginning to end or have you just brought the chlorine up to slam level a couple of times?

A SLAM does not end until 3 things happen -

  • CC is 0.5 or lower;
  • You pass an OCLT, ie shows a loss of 1.0 ppm or less);
  • The water is clear. (including no visible algae)
So, have yo followed the directions to the end?

 

Frezel

Active member
Jul 6, 2018
40
Doylestown, PA
i think you are keeping your fc a little low
throw in a bit of cya test error and makes it worse
after you slam try keeping your fc a little higher
You could be right I mean I fill that area up to the top around 20 and still sort of see the dot when testing cya. Last year my cya was 110 this year it might be 10 lol . That cya test is so subjective I don't think I ever seen that dot truly ever disappear
 

Frezel

Active member
Jul 6, 2018
40
Doylestown, PA
Pump run time has little effect on the proper chlorination of a pool unless the time is needed for a SWCG to generate adequate chlorine.

You say you have SLAMed your pool. Have you followed the directions from beginning to end or have you just brought the chlorine up to slam level a couple of times?

A SLAM does not end until 3 things happen -

  • CC is 0.5 or lower;
  • You pass an OCLT, ie shows a loss of 1.0 ppm or less);
  • The water is clear. (including no visible algae)
So, have yo followed the directions to the end?

Ok well pool is sitting at 12 ppm CL as what pool math gave me based off my parameters we shall see what it does over night and my CC was 0.5
 

Frezel

Active member
Jul 6, 2018
40
Doylestown, PA
i think you are keeping your fc a little low
throw in a bit of cya test error and makes it worse
after you slam try keeping your fc a little higher
I might raise my cya to 40 or keep my FC just alittle higher. I mean I only add about a cup a day of 12.5% chlorine in a 27ft round pool
 

Frezel

Active member
Jul 6, 2018
40
Doylestown, PA
So last night my pool went from 12ppm to 11.5ppm this morning the pool is not sparkly clear as you can see and there is what appears to me as alagae at bottom. Is my low cya affecting slam? According to pool math with a cya of 20 my slam was 10 which I went higher. Currently I have the pool vac running to clean up bottom and filter is running on high 24/7 . I did backflush what do 109700you guys think ???109699
 

Frezel

Active member
Jul 6, 2018
40
Doylestown, PA
That is 0.5 ppm FC added per day. Your pool is not holding a minimum FC all the time doing that.
I usually do not loose alot of chlorine as my pool gets about 4 hours sun and is lightly used during the week I keep it between 3-5 never below 3 by adding about a cup a day it keeps me there is this method wrong?
 

Frezel

Active member
Jul 6, 2018
40
Doylestown, PA
Let's see, where to start?

1. Algae simply does not appear in a pool that is adequately chlorinated however that chlorine has to be maintained 24/7 at that adequate level.

2. So it would seem at some point your chlorination has gotten too low. To get your pool back to crystal clear (and eliminate ANY sign of algae), you must follow the SLAM process. It is a process and you must follow the article in Pool School precisely.

3, Before you start the SLAM I would add 20 ppm CYA to get your pool 30-40.....something you can test for a little better.

4. Start the SLAM and read every word of the article The SLAM process Your initial dose of chlorine should bring your FC to about 14 ppm.
The rest of your numbers are fine. Once you begin the SLAM, you only need to test for FC and CC.

Do you have a pic of your current pool water?
I slammed pool but didn't add cya as stores were closed can I add some cya during a slam process? I would test to see what new level is after slam. Pool math has me adding almost 1 gallon to raise from 20-40
 

duraleigh

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Let's fix the terminology a little. You have not SLAMed your pool. You have started the SLAM process but you are not done.

Yes, you can add CYA during this SLAM but I am going to withdraw that suggestion now that I know you get so little sunlight.

So, you are in the middle of the SLAM process and you are replenishing your FC back up to 12 ppm at least twice daily, correct.

Vacuum that dead algae off the pool floor, backwash as necessary, and keep running your pump 24/7. You should see less and less of that dead algae on your pool floor and your pool should get clearer as you progress......it will be a daily improvement if you keep your FC up.