Brown streaks in semen

I've recently discovered that there are slight brown tinges in my ejaculate. There's no odour, no pain, no excess sensitivity, literally I feel completely normal (for now). I have done a bit of research on the web but all I found was that it could be old blood from being hit in the testes for example or excessive riding on a bike saddle. I have not to my knowledge recently taken a hit to that area (I think i'd know about it!) so it's not that.

Also I have not recently changed my diet, although last night I drank quite a lot of cider, which I normally drink but it doesn't normally cause this.

Basically I was wondering whether there's anyone who has had this before and could tell me if it just went away or what they did to get rid of it.

I'd also appreciate it if people could spare the stupid comments, about anal sex and the like (which I havent done btw), as this could be a serious problem so I would like to get people's useful experiences of this. Thankyou.