Noob questions, The Machine

[curious aardvark]

go for the black widow and do the sensible thing and just don't go anywhere near abs.

pet-g is damn near as cheap these days, much much easier to use, doesn't need a heated chamber and is resistant to just about all chemicals, also food contact safe so it won't kill your fish :-)
$25 a kg and cheaper: https://www.amazon.com/eSUN-filament...rds=esun+pet-g

Abs is way more hassle than it's worth. I mean way way way more hassle !

I'd also be inclined to try pla in the salt water setting - can't see any problems, also unlikely to poison your fish.
Bear in mind that abs filament often has additives to help the printing process and isn't considered food safe as it can leach chemicals.
Tropical Fish in tanks seem to spend their lives just looking for ways to die ;-)

If you don't have tropical fish - ignore all the fish references :-)

I spent 6 month fighting abs before I came to my senses. Haven't touched it in the 2.5 years since and never needed to.

There are a bunch of new abs beaters coming on the market as well.
I can thoroughly recommend innofil's new Pro 1
has to be the easiest filament to print I've yet tried. Costs more than pet-g - but you're pretty much guarenteed perfect prints every time.

As far as bed size goes. Mine are 9x6x6 inches and to be honest in 3 years I've yet to need anything bigger.
What i tend to find is that if I need to make a large thing I'll design a 3d printed part that attaches to a cheap existing 'thing' and do it that way.

As an example - my dad wanted some longer pegs to attach his pigeon decoys to.
So instead of printing long plastic pegs I simply made an adaptor that you inserted a cheap tent peg into and then slotted the existing pigeon stick in the top.
Gave a 10 inch extension for bugger all money and a lot less printing.

The thing to bear in mind is that 3d printing is slow. So what i do is look for stuff - often from a pound store that i can use with a 3d printed adaptor.

Another example. I have a tassimo coffee machine. So when making a pod holder for the kitchen. rather than printing it in one piece I made it in 3 quick to print pieces that were either joined together by bamboo skewers (1 pence each) or lengths of metal bbq skewers (12 for £1). That way I could make a much taller pod holder - and after a quick wipe with acetone, the stainless steel bbq rods look really good, for minimal printing and bugger all money.

Basically as long you are practical and used to making things - you probably won't ever need to print anything really big.