Trying to do SLAM but something dosen't seem right

[aces79]

I have a 30 foot round pool with some algae. Last summer I used the SLAM method and it killed all the algae and my pool looked great so I decided to do it again this summer.

My CYA is 45 and Ph 7.2.

I added the first dose of liquid chlorine yesterday afternoon. My FC is now 12.

If I'm looking at the pool math app correctly, I should be keeping it at 7 right?

Also, when I did it last summer, within hours my FC had dropped again and I had to add more chlorine. My FC has been holding steady at 12 since 3 pm yesterday.

That's not right, right?

My water is also still green.

I have a chlorine pool with a sand filter.

I'm using the TF 100 test kit.

 

[JJ_Tex]

SLAM level for CYA of 50 (45 rounded up) is FC of 20. Try that for starters. Also are you on a well or have any sort of iron in your water?

 

[aces79]

SLAM level for CYA of 50 (45 rounded up) is FC of 20. Try that for starters. Also are you on a well or have any sort of iron in your water?

Yes I do have iron in my well water.

 

[JJ_Tex]

Is the water clear and green, or can you physically see algae growing in places?
If you are in doubt if it is algae, do the OCLT to see if it is algae in your water that is using chlorine. Alternative causes to green water (especially if clear) could be iron/metals in the water.

Perform the Overnight FC Loss Test (OCLT)

The Overnight Chlorine Loss Test tells if the SLAM is finished or if you need to start a SLAM. This article says how to do the OCLT.

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