Why does adplugg-iframe keep increasing it's height?

AdPlugg iFrames are designed to resize to fit the size of their contents (by default).  So if your ad has a fixed size, the AdPlugg tag will stay fixed to the size of the ad.  If your ad's size changes, the AdPlugg tag's size will change to fit the ad. This makes it so that you can have responsive HTML5 ads such as this one.  If you want to control the size of the ad, you can either fix the size of the HTML5 ad's source content so that it is the exact dimensions that you want.  Alternatively you can set the width on the AdPlugg ad tag.  To set the width on your AdPlugg ad tag, add something like the following CSS to your site's stylesheet:

div.adplugg-tag[data-adplugg-zone='testing_html5_ad_v6'] {
    width: 300px; 
}

In the above CSS we are telling the browser to find a div with a class of "adplugg-tag" and a "data-adplugg-zone" attribute of "testing_html5_ad_v6" and to fix its size to 300px.

Additionally, you can fix the size by setting a fixed width on whatever element the AdPlugg ad resides within.  On your site, that would be the <div class="col-md-3 col-sm-12 col-xs-12 aside pull-left"> tag.  Set a fixed with on that element and the AdPlugg ad will be stay bound to the size of its container.