Stain slowly increasing over last three years of owning pool

[banjeman]

I'm not sure if it's a typo, but their current price for Iron Out is very cheap:

Super Iron Out IO30N Rust Stain Remover

Ascorbic Acid Powder

So Vitamin C is used to put the iron back into the pool? Or does Iron Out and the Vit C do different things. I ask because I have a 13.5k pool and wondering if I need to go ahead and get 2 lbs of Vit C or just a small bottle to test first?

I know I am not at that stage yet, as I still need to verify it will work with testing a spot. With that being said as you know I have a SWCG and IntelliPH. I notice in your process you say use bleach to bring up chlorine. Do you think I can get the same affect with an SWCG? plus once chlorine comes back you say to use borax to slowly bring up PH, I assume my intelliPH will allow me to do that no problem. Is there any affect to my salt PPM in the pool while doing this treatment (i.e. will it reduce salt levels).

I am just trying to make sure I fully understand how to bring the system back up after treating.