haha, I made the same mistake last year: Bought the standard size box springs. I called US-Mattress hotline, they told me that I cannot exchange it for the low profile box spring. My suggestion to you is: you can buy low profile box springs from local dealers. You can check them out on the Craigslist. You can buy two twin-size low-profile box springs for your king bed. I think it's around $160 for two. I haven't bought them, so I am still climbing up to bed each and every night ...