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@Leonie-Kramer Yes, we are using Wordpress. I can see if changing the slug to not include spaces may help. @lynnp I noticed that too! Usually our developer doesn't help with technical SEO problems like this, so I was trying to solve it myself But I will try to see if he can take a look at it. Thanks to both for your answers!

You would use Google Webmaster tools to remove a page from Google Search index. On the Webmaster Tools home page, click the site you want. On the Dashboard, click Google Index on the left-hand menu. Click Remove URLs. Click New removal request. Type the URL of the page you want removed from search results (not the Google search results URL or cached page URL), and then click Continue. How to find the right URL. The URL is case-sensitive—use exactly the same characters and capitalization that the site uses. Click Yes, remove this page. Click Submit Request.

I agree with the rel="canonical" that is the definitive way to solve the issue. The urls are not actually two different urls, they are using a query string. If you put a redirect into place, you might lose the functionality of the query string. Also, GA uses query strings for tracking, so you would also lose any GA tracking you are using on the main site page. Most people use rel="canonical" to solve this issue. I know when I blog and I link to a site I normally put a query string in the url I link to just to give them an idea of where the traffic is coming from and to make it easier to track.