It's a tank I already have. Yes, I know about acrylic scratching and once I use GS & silicone on it, there no "scrape it off and go back to aquarium". Thoughts? I have 2 glass enclosures as terrariums now.
I've used acrylic for almost all my builds! Check out my post history for a couple build logs and of course feel free to ask questions.
Would mention two things
1) Great stuff doesn't stick as well to acrylic as it does to glass; it comes off pretty easily (perhaps too easily)
2) Same for silicone - so would make sure to apply plenty and triple check the edges are sealed to avoid water slowly coming in and wearing it off
Also you can polish acrylic.
That said if done right / laid out correctly you can absolutely work with acrylic - just as good as glass, if not better. For example, things I've done (mostly for larger builds) is to add stainless steel cables to support / hang larger pieces of wood from the lid / upper edges - super easy / cheap to work with.