I often used to have watery stools while in remission. There are a bunch of theories about why. 1) we also have IBS (I think saying I have IBS is the same as saying I have diarhea--it doesn't tell me anything), 2) lasting small scale damage to our intestine, 3) dysbiosis. It could be something else entirely. My gi wasn't surprised but did feel more medication wouldn't help. I will say for me SCD and yogurt have helped. It's not a panacea but my stools are now mostly (but not entirely) formed. Who knows what it's all about.
Edited to say just read your other post. I also respond well to antibiotics. My GI said some people do but it never lasts. He said he thinks their effect shows that for some with uc dysbiosis is the main problem. They just can't figure out how to treat it permanently.
this all makes sense. dysbiosis may be the distal cause. It would have to be mediated by issues with mucosal membrane, since the proximal symptom is failure to absorb.
In addition to damage to the mucosa, there could be some issue with electrolytes. Absorption requires osmosis, where water exists colon and enter tissues and blood vessels. But if the mineral balance on each side of the osmotic membrane is not favorable, the water does not move.
possibly a duiretic will lower water in tissue, thus concentrating minerals/salts, and water will again move form lower to higher concentration of minerals. BUT use of all but weak OTC diuretics should be done under doctor's care. Don't risk kidney damage.