Help for my betta, please

[Pittsburgh_Fish_Nerd]

Hi, everyone! This is my first post here and I’m so glad this forum exists. I’ve been struggling with facebook, trying to get help for my male betta. Problems started about two weeks ago. He became very lethargic and was staying in his cave all the time, but it seemed like he was having trouble staying down, like swim bladder issues. It’s progressed to the point that he is at the surface, turned on his side, all the time. He’s still interested in food and can swim okay to get to it. But, the tips of his fins are a little bloody, though the water parameters are good. Could it irritate his fins to be just floating there like that all the time? Also, I’ve tried fasting him for two days and it didn’t have any effect. I just finished the first round of Cory’s recommended meds trio, minus the
Ick-X because he’s so weak. There’s been no improvement. The only other creatures in his tank are ramshorn and pond snails. I’m including a photo showing the sand substrate, which seems overly dirty. Maybe from the snails? Could this be irritating him? Every time I gravel vac, it’s back in a few days. Thank you so much to anyone who can offer help. I hate to see him like this, but I really want to believe there’s still hope. He’s not very old at all and is normally such an active, engaging boy. 
 

10 gallon tank, sponge filter, heater set to 80 degrees

ammonia-0ppm

Nitrite and nitrate-both 0ppm

KH is 40ppm

GH is 120ppm

pH-6.9 All tests done with API and Tetra test strips. 
 

He is fed a rotation of Fluval Betta Bites, Tetra BettaMin and I just started introducing frozen brine shrimp, which he’s had once. 

[Cory]

Do you know when the last time he was able poop? This is usually either constipation or organ failure which leads to fluid build up. If it's constipated, fasting/brine shrimp can work. As for the mulm on the substrate, I wouldn't worry about it.