I’m pretty sure my family has one for drinking water I’m not sure if there are different types or if it will work but I will include a picturemy suggestion is this:
drill now or not at all. it will be so much work to drain the tank move it drill it then set back up.
sounds like you are on a pretty tight budget so I would just go with a HOB filter and call it a day. maybe two smaller one vs one big one?
there will be so many things to buy like heater, lights, rock, sand, ATO, Fish corals if you go that way. it all adds up fast.
what are you going to do for water? buy RODI or make it. save the $$ for drilling and get a small RODI unit you will be happy you did.
with water changes 10% every week = 4 gal HOB filter and a HOB skimmer you will be fine
I ran a 40br holding talk like that for year while we where doing reno on the new house.
good luck let us know if you have an questions.