Nice! This is going to be an epic tank! Looking forward to seeing your progress. Do they intend to build it on site, or ship it to you already built?
Have you considered going with acrylic? A glass tank with these dimensions is probably going to weigh upwards of a ton! The seams on acrylic tanks are much stronger and acrylic itself is much stronger than glass. Acrylic also has much better insulating properties. All else being equal, an acrylic tank may actually end up costing you less than glass.
For a tank this size I would go with an Ultima II 2000; you will have to backwash less frequently which it sounds like is one of your main goals (less maintenance). I agree with what others have said in regards to the 2 head; it is better because it creates less friction loss.
I would consider using different pumps from what your builder recommended. There are far more efficient pumps on the market that will save you lots on your electric bill and give you a lot more flow per watt. Below is a quick breakdown:
Sump Pump: Instead of the Water Blaster, consider a Laguna.
Water Blaster HY 10000- Does 1,300GPH @ 6 head pressure on 175 watts.
Laguna Max-Flo 4200 Does 2,935 GPH @ 6 head pressure on 160 watts.
With the Laguna you get over twice the amount of flow, while using 15 less watts. Its also less expensive. I have been running a Max-Flo 4200 for over a year and I am very happy with it (very quiet, well made and efficient pump with a 3 year warranty).
Ultima II 2000:
I would run a Reeflo Super Dart Gold on the Ultima II 2000. It gives you about 2,200GPH @10 head while drawing only 178 watts. The Blue Line (although I understand they were recommending it for the Ultima II 1000) only does 600GPH @ 10 head on 180 watts. You can run the larger filter with much more GPH on about the same wattage by using the Reeflo Super Dart Gold.
Note that the Ultima II 2000 models and larger are too tall to fit under a 32 tall stand.
I dont understand your builder's filtration design sketch. It looks like the left overflow box drains into the sump (which is fine) and the right overflow box is feeding the Ultima (which would not be a good idea). In order to be able to backwash your Ultima, you want the intake to be well below the waters surface (running a closed loop), otherwise you run the risk of not having enough water to fully backwash/clean the filter. Having the Ultima draw water from an overflow also runs the risk of drawing air into the unit, which is not something you want to do. If the intent is to draw water from the sump I think there are two good reasons not to do it this way: 1. You lose the ability to draw poop from the bottom (my tank is setup this way, with only surface skimming and I have to vacuum poop off the bottom all the time if I could do it over, I would have something to draw water from lower levels of the tank) 2. You may run out of water to backwash the media if all you have is water from your sump.
Heres what I would recommend:
Sump Filtration:
Plumb both the left and the right overflow boxes to drain into your sump. This will give you good surface skimming on both ends of your tank.
Ultima II 2000:
Drill two intake holes near the top of the back panel of the tank. Insert an elbow off of the bulkhead on the interior of the tank and run a pipe to the bottom of the tank to suck poop off the bottom. If you are having a background installed on the tank, it would be pretty easy to hide the pipes. I think this is how Pacumom has her tank setup and I think that's how she's going to run her new tank...I really like that design because if there are ever any issues with the bulkheads, it'll be easy to service/replace them (just drain a few inches of water and you're good versus having to drain the entire tank if the bulkhead were on the bottom. The odds of catastrophe are much lower when your bulkheads are high up on the tanks walls, versus on the bottom panel.
In regards to your returns, I like to run mine in from the top of the tank. You would obviously want the return for the sump to be at the waters surface so that in the event of a backsiphon, your sump doesnt flood. The return for your (closed loop) Ultima can be anywhere, but I would probably have it coming in from the top of the tank as well.
Heres a visual of how I would configure your drains/intakes.
Have you considered going with acrylic? A glass tank with these dimensions is probably going to weigh upwards of a ton! The seams on acrylic tanks are much stronger and acrylic itself is much stronger than glass. Acrylic also has much better insulating properties. All else being equal, an acrylic tank may actually end up costing you less than glass.
For a tank this size I would go with an Ultima II 2000; you will have to backwash less frequently which it sounds like is one of your main goals (less maintenance). I agree with what others have said in regards to the 2 head; it is better because it creates less friction loss.
I would consider using different pumps from what your builder recommended. There are far more efficient pumps on the market that will save you lots on your electric bill and give you a lot more flow per watt. Below is a quick breakdown:
Sump Pump: Instead of the Water Blaster, consider a Laguna.
Water Blaster HY 10000- Does 1,300GPH @ 6 head pressure on 175 watts.
Laguna Max-Flo 4200 Does 2,935 GPH @ 6 head pressure on 160 watts.
With the Laguna you get over twice the amount of flow, while using 15 less watts. Its also less expensive. I have been running a Max-Flo 4200 for over a year and I am very happy with it (very quiet, well made and efficient pump with a 3 year warranty).
Ultima II 2000:
I would run a Reeflo Super Dart Gold on the Ultima II 2000. It gives you about 2,200GPH @10 head while drawing only 178 watts. The Blue Line (although I understand they were recommending it for the Ultima II 1000) only does 600GPH @ 10 head on 180 watts. You can run the larger filter with much more GPH on about the same wattage by using the Reeflo Super Dart Gold.
Note that the Ultima II 2000 models and larger are too tall to fit under a 32 tall stand.
I dont understand your builder's filtration design sketch. It looks like the left overflow box drains into the sump (which is fine) and the right overflow box is feeding the Ultima (which would not be a good idea). In order to be able to backwash your Ultima, you want the intake to be well below the waters surface (running a closed loop), otherwise you run the risk of not having enough water to fully backwash/clean the filter. Having the Ultima draw water from an overflow also runs the risk of drawing air into the unit, which is not something you want to do. If the intent is to draw water from the sump I think there are two good reasons not to do it this way: 1. You lose the ability to draw poop from the bottom (my tank is setup this way, with only surface skimming and I have to vacuum poop off the bottom all the time if I could do it over, I would have something to draw water from lower levels of the tank) 2. You may run out of water to backwash the media if all you have is water from your sump.
Heres what I would recommend:
Sump Filtration:
Plumb both the left and the right overflow boxes to drain into your sump. This will give you good surface skimming on both ends of your tank.
Ultima II 2000:
Drill two intake holes near the top of the back panel of the tank. Insert an elbow off of the bulkhead on the interior of the tank and run a pipe to the bottom of the tank to suck poop off the bottom. If you are having a background installed on the tank, it would be pretty easy to hide the pipes. I think this is how Pacumom has her tank setup and I think that's how she's going to run her new tank...I really like that design because if there are ever any issues with the bulkheads, it'll be easy to service/replace them (just drain a few inches of water and you're good versus having to drain the entire tank if the bulkhead were on the bottom. The odds of catastrophe are much lower when your bulkheads are high up on the tanks walls, versus on the bottom panel.
In regards to your returns, I like to run mine in from the top of the tank. You would obviously want the return for the sump to be at the waters surface so that in the event of a backsiphon, your sump doesnt flood. The return for your (closed loop) Ultima can be anywhere, but I would probably have it coming in from the top of the tank as well.
Heres a visual of how I would configure your drains/intakes.
