Ok, so this is an odd question. On my Genesis I cant for the life of me get the front off so that I can mount it/access the candela switch. I tried pushing down the black tabs on the top and only one goes down, the other only barely goes down, not enough to get the cover off. An ideas?
Try giving it some elbow grease. 
Some of those snap-on type alarms can be a little tough, you just have to man-handle them.
Even pushing as hard as possible it won’t come off. 
I usually use a small flat head screwdriver/thumbtack to get it off. I push the tab all the way down and then into the cover, so it’s just under it, and then do the same to the other one and it comes off with no trouble. Try that if you haven’t.
If you had a second generation SpectrAlert classic horn, horn/strobe, remote strobe, and the like, and it came with the “removal tool”, I’d find the “removal tool” a bit useful in terms of taking off the front cover.
Source: Got a gen-2 SpectrAlert classic remote strobe that came with the removal tool, and tried it on both my Genesis horn/strobe and remote strobe.