Hello, I'm currently researching saltwater aquarium keeping, I have 180L (approx. 50gal) aquarium and I'm trying to start my journey into saltwater with it. However I'm on a very tight budget. So I was wondering if I could use an internal filter(although it's from freshwater and has intake in the bottom and output on top) or do I make my own DIY AIO. If so what size and volume should it be to be sufficient enough for the 180l tank?
