Now What??

[supgirl]

Definitely going to leave the tank with the 3 Puffs, some cleaning crew and the current ghost shrimp for snacking (if they ever decide its worth the effort). I'm sure hoping they as big as you all have said. Anyway, they are a lot of fun to watch.

I will try to figure out a way to add the other filter, as I know this would be very beneficial, but I think I've read in some other posts, these guys can jump. The only way I could mount this additional filter would be to have it on a side wall, but that would require leaving one of the lids off. I definitely don't want to loose a Puff due to its jumping out of the tank

[bertie 83]

You could cover the gap with eggcrate. Or dare I say it modify your lid. Tank manufacturers are not the best at giving many filtration options

[Pufferpunk]

Engineer gobies are great substrate cleaners but they will also pile it high in different areas of the tank. Don't expect anything to remain where you put it. They also grow to about 18". It is the only fish I own that I actually HATE.

Forget about the slow-moving, sedentary blenny. It will be torn up by the puffers. So will the hermits.

Considering the suggested tank size for a single GSP is 30g, at 75g, you will already be overstocked when those GSPs are the size of 3 Nerf footballs.