[AnAmericanMother]

Excess salt consumption will cause her to urinate excessively. If she is licking the salt block out of boredom, she will get too salty and then drink a ton to try to straighten it out. And then she will pee oceans and rivers (it sure looks like that's what she's doing!)

Take away her salt block completely and see if that doesn't solve the problem. Once her system has had a chance to stabilize, you can give her an appropriate amount of salt sprinkled on her feed.

And find her another stall vice!

(there are tons of causes for polyuria (excessive urination). Try this first because you know she's been after the salt block and it may be out of boredom.)

[HairOfTheDog]

The excessive salt licking is either a cause or a symptom of the pee, I agree.

She doesn't have a salt lick in her stall, so she doesn't lick salt all night, she has access to a big block outside during the day when they are out.

We put the block (s) back out Sunday. I'll consider taking it away again, though I hate to take it away from the other horses too, and I hate to take it away if in fact she is depleting herself and needs it.

I put them back out on the front pasture yesterday, which usually makes them less bored during the day. They prefer life out there over the back forty, not sure why.