Yes, clen can very much give you cramps. Drink massive amounts of water. If you think you drink a lot now, drink more. Drink enough that you have to get up at night and piss, and when you do, drink more water. That, and get more potassium. I used to think my MRPs took care of it, they don't. Add some bananas or something in there. That's what I did, and it's solved my problem. I've been plagued with cramps all my life.
-B