Thank you for the reply.
Since the last post we have found out that Alex has Urethral spasms and therefor has problems passing the urine. They did catheterized him and there are no crystals. The ultrasound showed nothing also, he is on an antispasmodic now and doing well. Keeping fingers crossed...
I have a cat, Manx, about a year and a half. I've always had female cats before so when he started having issues with grit and minerals in his urine I was not prepared. We live in an area that is notorious for having a lot of minerals in the water. It destroys hot water heaters and clogs up...