As Liam said, the green bubbles are yep, bubble algae, dont be tempted to pull them off or indeed muck about with them as they will release spores and you will get loads
emerald crabs will eat it, but takes a while!
You have 'crud' and coraline on your powerheads - the purple is the coraline and can easily be removed by an overnight soak in vinagar, do one at a time, so you always have a powerhead going
the crud will just wipe off (by the way, crude is a technical term
)
Buy yourself a nice long handled Kent scraper for the back and a good floating algae magnet for the front.
It looks to me like you put back the old sand, or maybe it never came out - if htis is the case, research nitrate and phosphate removers, as I suspect you are going to need them
Seffie x
ps glad everything made it through the night