If you have enough plants you don't need to gravel vac. Re the collection I don't know enough about plants to choose my own yet. Maybe in 12 months I would do differently but for £17 for 103 plants can you go wrong?
Why wouldnt you have to gravel vac if you have loads of plants?
I understand that if you had 100% ground coverage that you could vac the plants and the sand would remain relatively untouched but otherwise your still going to be left with loads of poop on the sand that looks bad