Again, excellent info/write up! It's funny you mention engineering. While I'm not a mechanical/electrical eng, I am a data engineer/IT nerd by day, very DIY friendly and very Type-A (I'm a big time planner), so I've been working on and considering your suggestions from the beginning of this project (power, water/sewer, etc). I lucked out and got an already pre-built 6 zone manifold (which I was planning on building) from a LFS that was going out of business, including an Alita AL-80, which is why air driven filtration is so appealing in this situation. All the tanks are drilled. I have a hot and cold line in the unfinished section of the basement that I'll sweat two new coppers tees on and run the pex to the manifold.
Currently I only have one 60g setup (which will be the 120G sump when this is all finished), but with the LFS going out of business I got killer deals on tanks. 1 120G, 3 40G Breeders, 1 50G Low boy, and 8 20g Highs.
Doing the math, my basement office is fully insulated and is typically the most consistent temp room in the house. It would be cheaper to run individual heaters than using a 1500W room heater to keep temps.
I don't need all 6 zones, so I'm planning on just using three for now. 1 for the 120, 1 for the rack of 20s, and 1 for the 40 breeders.
After reading through your notes and looking at my variations, my goal is to have a few showcase tanks (the 120, 40 breeders and 50 low boy) and then the 20s for grow out/breeding tanks (bare bottom with lots of floating plants). This would also drop my cost significantly on scaping every tank as well.
The issue that had me stalled for a bit was drainage. I don't have an easily fed gravity drain anywhere close to my basement office, so the plan is to have a sink sump pump at the lowest point with the tanks to be plumbed into the existing PVC shower drain that I'll put a Y pipe on for drainage.
For safety/failsafes, I'm planning on doing small drip irrigation water changes of 2-4 gallons for the smaller tanks every few days so the water volume wouldn't be too much to overwhelm the sink utility pump if I felt like running all the zones at once for an extended period of time. For the 120 I'm planning on doing 10-20 gallons every 3 days, and having a secondary pump (not tied into the return) that will have a float valve to eject any water past a certain point in the sump into the sink utility sump.
The changes won't be automatic on a timer, but rather the push of a button from my phone for each individual zone for when I'm home so I can monitor the changes (I work from home in the same room). I'm also exploring some automation around water sensors that if they were triggered the manifolds would close to stop new water from coming in on all the tanks and would shut off the return pump as an additional precaution.
If you've got 40 gallon breeder/20G High rack designs (I'd prefer to build than buy) I'd love to see the measurements and cutlists!
