please help with SLAM-algae

[abfab]

So, I have a green clear pool with algae. Using the K2006 kit I just got I have the following chem levels:

FC = 4.4
PH = 7.8
TA = 110
CH = 130
CYA = 45
Salt = 2900

From what I read in pool school I need to shock to 18. I know I need to lower the PH to 7.2 before adding chlorine. I know muriatic acid is recommended but is it ok to use dry acid?
I'm confused with the pool calculator. If I enter 18 as my target it says I need about 10L of 12.5% bleach to get to this level, but at the bottom it says adding that amount (10000ml) will increase my fc by 27. Did i do something wrong?? which is correct?

 

[one_knight4u]

Neither,,,, you have some numbers entered wrong somewhere.

I show 5.4 liters of 12.5% chlorine to bring it up to 18 from the 4 you are at now.
10 liters (10,000 ml) will raise it by 25 + the 4 you are at now for a total of 29.

 

[BoDarville]

So, I have a green clear pool with algae.

Just to be clear...is your pool green, but clear (as in there are no green splotches on the pool walls and you can see to the bottom) or is it green and dull/murky? Green and clear is usually a sign of metals in the water whereas green and dull/murky with green clumps on the pool walls are signs of algae. We can rule out metals if you are on municipal water (e.g., not a well) and do not use any products containing copper or other metals. Wanted to bring this up since the treatment for these two conditions is very different.

 

[pwrstrk]

I agree with Bo. A clear green with no visible algae points towards metals in the water. ?

 

[abfab]

The pool is green but clear (I can see the bottom) with yellow-brown sand-like algae only on the floor only. From what I've read this indicates regular algae not mustard algae. I am brushing the floors and walls (just in case) to loosen everything up.
My salt level got too low causing the swg to stop generating while I was on vacation.

Thanks for clarifying one_knight4u. I have a 10L jug and for some reason I was fixated on the 5L jug size and was multiplying by 2 instead of focusing on the amount. I got 4971ml when i entered 4.4 to 18, which I rounded to 5L then erroneously doubled. Oops! Makes sense now.

 

[one_knight4u]

Not a problem, it happens to the best of us....

and was multiplying by 2 instead of focusing on the amount

but does that mean if i give you $10, multiply by 2 and give me $20 back....Lol....

Good luck and have a great day.

 

[BoDarville]

abfab: Thanks for the extra info.

If the SWG stopped generating, that would certainly cause the chlorine to get too low which opens the door for algae. We will proceed under that assumption. Follow the target shock levels outlined in the Chlorine CYA Chart or PoolMath. Also, check out the SLAM- Shock Level And Maintain article. The most important part of the SLAM process is the M for Maintain (as in maintaining the chlorine level as close to the target as possible). Doing this will speed up the SLAM process.

 

[SunnyOptimism]

Do you know the cause of your salt going low? Salt doesn't usually change much over a swim season unless you are backwashing a lot of water and refilling.

How did you test for salt?


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[abfab]

Update:
So a couple of days in my pool is looking much bluer and clearer, but it still has a slight green color (aqua-teal and I can't see the bottom clearly yet). I've been checking the fc about every 3 hours or so during the day and adding chlorine as prescribed by the pool calculator. I always made sure it was at 18 at night but in the morning it usually dropped to 16. CC has been 0 before and during SLAM. I have been brushing the pool twice a day. This morning my fc was the same as yesterday. Also, my swg is still off.
The problem however, is that I can still see some algae in the shallow end in the morning. What have I done wrong?? Did my fc get too low? I haven't backwashed yet as my psi hasn't changed (replaced gauge in the spring). Also, I haven't vacuumed as I wasn't sure if it is ok to use my robot (Z5) with high fc. Are these my problem??? Should I increase my FC?

- - - Updated - - -

Do you know the cause of your salt going low? Salt doesn't usually change much over a swim season unless you are backwashing a lot of water and refilling.

How did you test for salt?


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We've had unusually cool nights this summer so we've had to refill due to evaporation (don't have solar cover). I should be keeping it at about 3200 but wasn't very good about checking it as it normally doesn't change. The reading is from the panel which has always been similar to the pool store reading.

 

[SunnyOptimism]

Update:
So a couple of days in my pool is looking much bluer and clearer, but it still has a slight green color (aqua-teal and I can't see the bottom clearly yet). I've been checking the fc about every 3 hours or so during the day and adding chlorine as prescribed by the pool calculator. I always made sure it was at 18 at night but in the morning it usually dropped to 16. CC has been 0 before and during SLAM. I have been brushing the pool twice a day. This morning my fc was the same as yesterday. Also, my swg is still off.
The problem however, is that I can still see some algae in the shallow end in the morning. What have I done wrong?? Did my fc get too low? I haven't backwashed yet as my psi hasn't changed (replaced gauge in the spring). Is that my problem??? Should I increase my FC?

- - - Updated - - -



We've had unusually cool nights this summer so we've had to refill due to evaporation (don't have solar cover). I should be keeping it at about 3200 but wasn't very good about checking it as it normally doesn't change. The reading is from the panel which has always been similar to the pool store reading.

Evaporation and refill would not cause you to lose salt. Only splash out and backwashing a filter (water volume loss with fill replenishment) would change salt levels.

I would suggest you get some AquaChek test strips for salt or the Taylor salt reagent drops (both available for purchase on Amazon). I think you need to get a handle on your salt levels. My local pool store was always way off on salt measurements and a bad reading by them caused me to overload my pool with salt (corrected before the swim season). Now I check it myself monthly.


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[BoDarville]

So a couple of days in my pool is looking much bluer and clearer...The problem however, is that I can still see some algae in the shallow end in the morning. What have I done wrong??

I don't think you have done anything wrong. You are seeing progress and that's proof that it's working. The SLAM can (and usually does) take more than a couple of days. In some cases, it can take a week or more - there is no set timetable. The 18 ppm FC that you are using for a CYA of 45 is a target, not an absolute minimum. If you are within a couple of points +/- from that target at any given time, you will be fine. Just keep the SLAM going and keep aiming for the target FC until you pass the SLAM criteria.

One other thing: If you have a pool light, ladders, or removable steps...clean around, under, and behind these items as algae likes to take refuge in and around these areas.

 

[abfab]

I don't think you have done anything wrong. You are seeing progress and that's proof that it's working. The SLAM can (and usually does) take more than a couple of days. In some cases, it can take a week or more - there is no set timetable. The 18 ppm FC that you are using for a CYA of 45 is a target, not an absolute minimum. If you are within a couple of points +/- from that target at any given time, you will be fine. Just keep the SLAM going and keep aiming for the target FC until you pass the SLAM criteria.

One other thing: If you have a pool light, ladders, or removable steps...clean around, under, and behind these items as algae likes to take refuge in and around these areas.

Thanks! My fc is holding pretty steady and water is getting bluer and clearer every day but still not 100% yet. The amount of algae forming seems to be less each day but its still the yellow-brown color, not seeing any gray.
Is it safe to use my robot to vacuum with this level of fc or do I have to do it by hand??

 

[duraleigh]

By all means, use the robot.

seems to be less each day but its still the yellow-brown color, not seeing any gray

That's dead algae indicating you still need to SLAM. Use the robot as often as you can,clean your filter often.

The SLAM involves killing the algae then cleaning it from the pool. Sounds like you are killing it just fine but not cleaning it from the pool often enough. Stay the course and clean a bit more often.