Hi all, I am new to beekeeping, and have spoken to lots of guys both pro and hobby. Yep it seems weird to put poison in a hive and that's why its important to be impeccable with your hive management. Keep strong hives, in the sun, and have a management program, what I worked out from almost everyone I spoke with, is no management will get you dead hives!
I am trialling the Blue bottom board, although I don't like that it does not kill the beetle, they get hunted out and move on. The theory is that the conditions don't suit the beetle re humidity so they wont stay anyway. Some are putting a tray under with Diamathius earth but this then defeats the ventilation factor. I have been told by guys that use them that there are no beetles in hive with blue bees bottom board. I am trialling it just to see for myself.
I use the Apithor trap, on the bottom boards as designed and have no problem. but at $7 bucks a throw, and it lasts only 3 months max, I am also trialling the other mentioned method of 5mm core flute with the gel in the centre. As someone else said, level hive left to right with slight tilt toward the entrance is how I set my hives up any way, just to deal with water, poison or not, but its my opinion that card board soaked in poison is more likely to have a water flow containing poison over a gel in the centre line of a 100mm trap.
Somewhere else on the forum here I saw the olive oil mentioned and he said he had killed beetles by the tons, that I like, because you can see the result, but its a mess when your moving hives, if I could get that one perfected I would be doing that as well.
As said, I have little experience but I do listen to everyone and take what makes sense to me.