If it was what I had on hand for potted plants, I would use it but as was said above, I would supplement it with Cal-mag . If this is an outdoor plant, I wouldn't spend any time worrying about salt build up. The rain water will be more than enough to flush the salts out. There are quite a few people out there that use MG and Cal-mag in their hydroponic grows where the plants get no other nutes and from everything I have read, they do fine.
I presume this is the 20-20-20 mix but you didn't say. If it is, that is a decent balance and peppers like balance since they are growing, blooming, fruiting and ripening all at the same time.