[DKoKoMan]

Depends on what direction you want to go (I know right!). There are a lot of options available out there to grow macro algae these days. If this is the primary purpose of the refugium you could explore options of a reactor. If you have a traditional refugium with chaeto, pods and sand than obviously a reactor won’t replace that. If you have the room you could easily pickup a manufactured tank or get creative and build one.

I would strongly suggest not trying to patch a crack, especially where you have drilled. That would make me worry all the time that I am going to end up with a flood. You can also go without the fuge and look at other methods for nutrient exportation. I personally use a refugium with a ball of chaeto as a primary means of nutrient reduction. I also use a reactor with a small amount of GFO if my phosphates rise. Hope this gave you some feedback to your questions.

Cheers,

Devin