....I've decided to use the 135 as a sump for one of the filter subsystems...
I very nearly laughed out loud when I read that.I discovered that I have an immense amount of stuff in my fish room. Tomorrow, I'm going to start sorting it all out to see what is actually useful and what I need to get rid of. That is after I get all the other stuff done.
Is this going to make your house unsellable, or are you actually adding equity? Your house is definitely going to be in a niche market now, hope you can find some rich hobbyist when the time comes to sell. I'd like to see your real estate agent pitch that house to a young couple.