They look great, and like the black substrate. I got into this the same way you did 4 years ago. I went with the advice of lfs store employees and ended up with a host of issues. I probably would have given up if I had not gotten some great advice on a forum. I learn something new just about everyday from other fishkeepers on forums.
Good to hear about your journey bro! They are captivating fish. A 300 gallon would be perfect for them. Don’t feed them goldfish by the way (in case you are) as they can get diseases and also google “thiaminase in feeder goldfish”. I’m Filipino too BTW enjoy your living fossils!