Help needed cleaning brine tank

[Jsmallberries]

Municipal water, Pentair tank, 18"x33" Round, hasn't been cleaned or stirred in about 2.5 years. There was about 2" of standing water on top of appx 7 inches of salt and sludge. The water was brown and the salt had a brownish tint.
Just cleaned it all. Couple of questions,

1) Can I reuse the salt scooped off the top after I drained the water and just toss the "sludge that was at the bottom?
2) How much water to add back in and do I need to fill the float cylinder?
3) Once water and salt back in , do a manual regen?
4) Anything else to clean or check??
5) What would cause this, and how to avoid in the future?
6) Best way to sanitize the resin tank?
Thanks, I did the install but forgot the basics since then 3 1/2 years ago,

 

[Jsmallberries]

I think the tank had "salt mushing" from lack of maintenance. I use Morton or Diamond Crystal salt pellets from home depot, so I don't think it's from dirty salt.

Cleaned the brine tank and did a manual regeneration.
I also purchase AO Smith universal Softener cleaner and will add 16 oz that to the brine well and do another manual regeneration.

Lesson learned, will keep up with basic maintenance, damn those 3 years flew by

 

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[Reach4]

What salt? You might switch from solar salt to pellets.

Any iron in your water? Are the insides of your toilet tanks rust-colored?

See https://terrylove.com/forums/index.php?threads/quick-question-how-to-sanitize-water-softener.82830/

During normal operation, there should always be some salt higher than the liquid.

 

[Jsmallberries]

Yes to salt pellets already used, municipal water, no iron, just hard water. No rust at all
My install manual says "it's not uncommon for water to be above the salt level as long as it'd not up to the overflow valve."
Section 4.7

 

[Reach4]

Yes to salt pellets already used, municipal water, no iron, just hard water. No rust at all
My install manual says "it's not uncommon for water to be above the salt level as long as it'd not up to the overflow valve."
Section 4.7

I think salt stratification is a thing. I disagree with your manual's comment, but that's the way it is. But Bannerman would tend to agree with you on this.

If stratification is real, expect to see the water in your brine tube higher than the liquid in the main part of the brine tank.

 

[Jsmallberries]

From my web searching it looks like what is called salt mushing not bridging.
Here’s one example “Salt mushing is when dissolved salt recrystallizes in the brine tank and clumps together to form granules. These granules usually collect at the bottom of the brine tank, where they can block the flow of brine solution out of the tank during regeneration”

Any one use the AO cleaner product
And is there a homemade option to clean the resin? I think bleach might damage the resin