Ad after every 3rd/6th post? Using Juggledads multi column/custom query template
 

Hey,

Any advice on this? I want an ad displaying every third or sixth post. I'm using Juggledad's multi column custom query template and I have three posts per column. So I want:

Post post post
ad
post post post
ad
post post post
ad
post post post

Or the same pattern but every third row (haven't decided). I tried checking for guides and adding a counter in the loop but it didn't work.

What should the code be on this template, to achieve this? Or is there a query for this?

Thanks!

Also; is there any way to use this template for categories and tags (and keep good SEO)?