Calming Supplements for HOT Ex-stallion?

My 11-year old TB has been really hot lately (I mean like so hot I can't get the saddle on lately because he freaks out). This is the first spring we've had him, and he was a stud for 10 years of his life (he was gelded last year) so I think he's probably just feeling like a stallion now that its breeding season, although he supposedly never bred. But its getting to be extremely annoying; he is also cold-backed (see my other thread) and I can't even mount him these past few days. I am trying taking him off what little pasture is growing now, and also I just took him off his joint supplement since I put him on a new one recently and wonder if that is contributing. I will let you know if that yields any results. Other than that nothing has changed recently in his routine. So I'm considering getting maybe calming supplements, like magnesium or Vit B for him, as the reviews on SmartPak say they help some horses. What do you think? Has anyone had this issue before with a stallion in the spring, or any experience with calming supplements?

What is his TOTAL diet??

He gets about 25 lbs of grass hay per day (the hay has a tiny bit of alfalfa, like 10 or 15 %, but he's been on it for a year so I don't think that's the problem), plus 4 lbs Purina Senior feed. He also gets 1 oz (1 SmartPak well) of the digestive supplement TractGard. Lately (I just took him off of it) he has been also getting 2 oz (2 SmartPak wells) of Absorbine Flex+Max joint supplement per day.

I actually have noticed a difference, the past three days he's been off the joint supplement! I really think that's been most of the problem, but I won't know for sure until I try to mount him later today. :P He's been off pasture for a week now so maybe that's helped too. Unless anyone can spot any other potential problems with his diet? Or has advice on handling an ex-stallion or a stallion in the spring? Has anyone had issues with their horse getting hot on pasture grass in the spring? He was fine on the same pasture last summer/fall...

I have a mare that gets stupid on grass in the spring
Also keep in mind that Purina Senior is grain based feed but being in CO that is probably about the only brand you can get easily.

Is he a hard keeper? Why is he on Senior feed?

I'd stay with the Senior but cut out any vitamin supplements. Seniors is a balanced feed that also aids digestion so feeding the others means you are making expensive poop and possibly overdosing some vitamins or minerals. I start out with just hay and only if the horse should start to lose weight would I add a pelleted feed or oats.

I'm trialing Command Serene and so far I'm super happy with it. Its an all natural supplement and it just takes the edge off.

Actually she is underfeeding the senior so it is not providing the needed nutrition as is

Yeah I'm very wary of overfeeding grain. I've always been taught that hay feeding is the best for horses, being grazers that they are. Also my horse is a very hard keeper (hence the Senior Feed and TractGard) but he gets hot very easily, so I have to be extremely careful of what I feed. Do you think I should take him off the TractGard? It is a fairly inexpensive supplement that is supposed to help with ulcers, and my horse has a history of being treated for ulcers in the past so I worry about them. It also has electrolytes and is supposed to help hydrate the GI tract. But if it is making him poop more then I'm all for taking him off! I do think it helps him keep his weight though.

I like to get my supplements from SmartPak; they have two supplements that are inexpensive and supposedly "calming"--Magnesium and Vit B1. I have absolutely no experience with calming supplements! Anyone tried these? Also any recommendations for a good, cheaper joint supplement (under $40) that doesn't make the horses hot?! :P

I use SmartCalm on my mare because she's anxious and can just be a jerk. It works wonders. It starts to work in about 2 weeks. Since he's been recently gelded and is much more of a handful than an uptight mare, I would try SmartCalm Ultra.

I have heard good things about that supplement. It's just a little more expensive than my budget wants to allow at the moment! I will keep that in consideration though, thank you.