Looking very good bro! As for the filtration it is better to have half in and half out as you suggested earlier. Reasoning is that when you are doing tank maintenance and during power outages not all of the biomaterial will dry out and die off. Filter sounds like it will work great to me. i get my scrubbies at the dollar tree here. it's $1 for a bag of like 6. So $10 for 60 so on and so forth. Always seemed too expensive to buy any other place lol. I've bought up several hundred at the dollar tree here because they seem rare these days but this store has tons of them lol. They might come in handy for the future so getting all I can lol.