One Ad unit in Iframe, one not, both are serving same ads

[flyerguy]

I have a banner ad management system that serves up an ASP file via Javascript.

There are two banner zones, top of page and bottom of page. The top one is an Iframe, which detects user connection speed, if the user is on dialup they get sent to a dialup service affiliate ad. If they are broadband, they get an Adsense 160x600 unit.

The bottom banner zone is always a 728x90 Adsense ad unit.

The top Iframe Ad unit is smart enough to detect the content of the page it's in, and delivers on target ads.

Problem is, it doesn't seem to be smart enough to notice the other ad unit is there, an consequently they both end up delivering the same ads.

I realize the Javascript is probably the failure point, but there's no way around this for managing thousands of pages.

Any ideas as to how to let one ad unit know about the other one so I get a proper spread of ads?

[bumpski]

Sometimes you have to wait several days or even a week for Adsense to crawl your site, then usually the duplicate ads go away.

I use IFrames for my Adsense ads, I may have mixed and matched as you are in the past, but now all my Adsense ads coincidentally are in one IFrame. I just saw a duplicate image ad, in the second and third Ad units. These are configured, image_text, and image_only respectively, this could contribute perhaps?

Make sure you at least visit all your pages each time you make an Adsense related change, unless your sure you have enough traffic to all the pages.