I had a HOB on my 65g it was the CPR brand with aqualift pump. I never had a issue with it breaking syphon (due to the pump sucking out any air and keeping the vaccum) However i never slept that great a night wondering if it would and would always check on power outages and restarts to make sure everything was working still. I bought my 90g drilled tank and i must say I love the drilled tanks no worries about restarts etc. BUT the space it takes INSIDE the tank but i would rather loose a little space inside the tank than a FLOODED house from a HOB.