Wow! You’ve got an awesome setup, Man! But aren’t the Laguna pumps for ponds? Do they work well for aquarium use? They look huge in the pics I saw so I’m wondering if space will be an issue?
As far as the glass vs acrylic debate, yeah, there are advantages to both. I just meant that from a business perspective, the reason many of the custom tank makers for large aquariums are pushing acrylic has more to do with their bottom line ( cheaper to ship and set up).
The plumbing part makes me nervous bc of my lack of experience in that area. I’m taking my time and trying to do it right. That being said, my Bala’s probably aren’t going to stop growing anytime soon.
Not sure what pix you are referring to, but if it's the pic of the gold pump, that's a Reeflo Hammerhead. Definitely a beast of a pump. That pump and several replacements leaked, so I returned those and ended up going with a submersible (a Laguna Max Flo 4200). It's the biggest model they sell (the newer version is the 4280). If your plan is to run a 125G sump, you'll have plenty of room. As I mentioned before, I would run two smaller pumps, versus one large pump. If you run one large pump, you're not going to end up saving any money because you should always have a back-up (replacement pump) on hand in case of failure.
It doesn't matter what a pump is marketed towards (ponds or aquariums); at the end of the day, they move water. You'll want something efficient, quiet and reliable and Lagunas check all those boxes. The "aquarium" version of the Lagunas is the Fluval Sea SP series if buying a "pond pump" is a concern. They use the same Askoll motor as the Lagunas, which is really nice quality. Mine has been running for 7 years straight and I've never even taken it out to clean it (although I know I probably should).
Those new Sicce pumps Ryan mentioned look good too, but since they are newer, they don't have a proven track record. I remember when all the cheap/knockoff DC variable speed pumps were first coming out and everyone was buying them. Turns out there were lots of issues/failures and some people lost fish they had kept for many years. I wouldn't want to be a guinea pig for something as important as the heart of your filtration system.
Since it sounds like you are looking to go 40" tall, I would make sure when you are getting quotes from builders (whether it's glass or acrylic), they clearly state the thickness of the sides, top and bottom of the tank so that you can make fair comparisons. The more reputable builders will use thicker material, which translates into higher cost. At 40" high, if you end up going acrylic I would say 1" should be the bare minimum thickness. I'm not sure about glass, but if it were me, I wouldn't even consider relying on a thin bead of silicone to hold 40" of water.
Balas do get big. There was a guy on here years ago that had some monsters that must have been 15"+. He would occasionally feed them pinky mice.