Multiple closed loops???

[Tonycass12]

So im in the early stages of planning right now. This past weekend I picked up a 10'x2'x2' acrylic tank. Unfortunately I realized on pickup that thos thing was constructed from 1" acrylic for all the sides and ¾" for the bottom amd top eurobrace. So using my 6 mp40s on this tank is not going to be an option. High flow is a priority, its going to be mostly sps in this tank.

Im looking at doing at least 2 maybe 3 separate closed loops now. This looks like it will be the most cost effective way to get the flow im looking for. I would like to do 2 separate closed loops on the bottom with each having 3 returns and possibly an additional closed loop on the top of the tank. Each of the loops would be powered by a 4k-6kgph external pump. I figured doing it this way would not only add some redundancy but allow me to scale it up after the tank is filled and livestock added. I could potentially start with just the bottom 2 closed loops and have the top one plummed but not necessarily hooked up right away.

Any opinions or thoughts on this plan? As much as I would like to use some vectras for the pumps they are just too expensive so I'll probably be going with hammerhead/barracuda hybrid pumps.

 

[143MPCo]

That’s a solid plan — the Hammerhead/Barracuda hybrids should move plenty of water, especially given that acrylic thickness. You’re right to go the closed-loop route here; it’s a great workaround when magnets won’t hold, and you’ll get super even flow coverage once it’s dialed in.
Definitely incorporate ball valves (or even better, true-union ball valves) on each return so you can fine-tune the flow and isolate sections for maintenance without a full system shutdown. With a few tweaks, you’ll have total control over turbulence patterns and can balance those loops perfectly.
This thing’s going to move some serious water — I hope your aquascape is ready for the “coral treadmill” treatment. How are you planning to route the bottom returns — through the base panel or back wall?

 

[Tonycass12]

That’s a solid plan — the Hammerhead/Barracuda hybrids should move plenty of water, especially given that acrylic thickness. You’re right to go the closed-loop route here; it’s a great workaround when magnets won’t hold, and you’ll get super even flow coverage once it’s dialed in.
Definitely incorporate ball valves (or even better, true-union ball valves) on each return so you can fine-tune the flow and isolate sections for maintenance without a full system shutdown. With a few tweaks, you’ll have total control over turbulence patterns and can balance those loops perfectly.
This thing’s going to move some serious water — I hope your aquascape is ready for the “coral treadmill” treatment. How are you planning to route the bottom returns — through the base panel or back wall?

I love high flow. Currently running 4 mp40s near max flow on my 120


Im still a little unsure of the routing for the returns. I could do them down the center or via the back wall. Not sure of any advantages outside going through the back wall may keep them in a location thats slightly more accessible and easier to clean the screens on the returns.

 

[143MPCo]

I’d also recommend adding individual valves at each return nozzle. That’ll give you precise control over flow rate and direction in specific areas of the tank — perfect for tweaking turbulence and eliminating dead spots once the rockwork and corals are in place.

 

[143MPCo]

I think you’re spot on about the back wall option — it’s got a few nice perks. Besides being way easier to access for cleaning and maintenance, it also keeps things looking a lot cleaner overall. Center returns can do great things for flow, but they tend to grab attention and break up that beautiful open viewing lane you’ll have.

With back-wall returns, you can tuck the plumbing out of sight and let your aquascape really shine. You could even hide the outlets just behind or above the rockwork so the flow looks totally natural — corals moving, water swirling, but no obvious hardware in sight. It gives the tank that “high-end showroom reef” vibe.

Little extras go a long way too — matching your nozzle color to the background (like black on a black back wall) really keeps the setup polished. Between cleaner visuals and easier reach for those screens, I’d say that’s the win-win route.

How’s your rock layout plan coming along? Are you leaning toward a minimalist structure or more of a dense SPS wall?

 

[Tonycass12]

I think you’re spot on about the back wall option — it’s got a few nice perks. Besides being way easier to access for cleaning and maintenance, it also keeps things looking a lot cleaner overall. Center returns can do great things for flow, but they tend to grab attention and break up that beautiful open viewing lane you’ll have.

With back-wall returns, you can tuck the plumbing out of sight and let your aquascape really shine. You could even hide the outlets just behind or above the rockwork so the flow looks totally natural — corals moving, water swirling, but no obvious hardware in sight. It gives the tank that “high-end showroom reef” vibe.

Little extras go a long way too — matching your nozzle color to the background (like black on a black back wall) really keeps the setup polished. Between cleaner visuals and easier reach for those screens, I’d say that’s the win-win route.

How’s your rock layout plan coming along? Are you leaning toward a minimalist structure or more of a dense SPS wall?

My plan for that would be 2 or 3 islands with the one closest to the overflow going right up to the wall. Im a big fan of the "short rock piles" keep the rock below the bottom 3rd of the tank and let the corals grow up and into the spotlight. This also has big advantages for flow that I noticed in my 120. You can really get all that water in the upper half of the tank moving to the point that you won't really have any dead spots in the lower portion of the tank. Also gives the fish tons of room to swim freely and I noticed unlike tanks ive had in the past with rock up to and over the center of the tank the fish tend to jump less as they go for the rock in the bottom to get under cover when spooked.

Lots still to think about. This will be a slow build that will probably take me most of this year to put togeather. I figured I would set up a build thread once I get things moved inside in the spring. Tank is currently stored in a trailer due to the 3'+ of snow on the ground.

 

[143MPCo]

I think you’re spot on about the back wall option — it’s got a few nice perks. Besides being way easier to access for cleaning and maintenance, it also keeps things looking a lot cleaner overall. Center returns can do great things for flow, but they tend to grab attention and break up that beautiful open viewing lane you’ll have.

With back-wall returns, you can tuck the plumbing out of sight and let your aquascape really shine. You could even hide the outlets just behind or above the rockwork so the flow looks totally natural — corals moving, water swirling, but no obvious hardware in sight. It gives the tank that “high-end showroom reef” vibe.

Little extras go a long way too — matching your nozzle color to the background (like black on a black back wall) really keeps the setup polished. Between cleaner visuals and easier reach for those screens, I’d say that’s the win-win route.

How’s your rock layout plan coming along? Are you leaning toward a minimalist structure or more of a dense SPS wall?

My plan for that would be 2 or 3 islands with the one closest to the overflow going right up to the wall. Im a big fan of the "short rock piles" keep the rock below the bottom 3rd of the tank and let the corals grow up and into the spotlight. This also has big advantages for flow that I noticed in my 120. You can really get all that water in the upper half of the tank moving to the point that you won't really have any dead spots in the lower portion of the tank. Also gives the fish tons of room to swim freely and I noticed unlike tanks ive had in the past with rock up to and over the center of the tank the fish tend to jump less as they go for the rock in the bottom to get under cover when spooked.

Lots still to think about. This will be a slow build that will probably take me most of this year to put togeather. I figured I would set up a build thread once I get things moved inside in the spring. Tank is currently stored in a trailer due to the 3'+ of snow on the ground.

Sounds like a great plan so far. The Hammerhead/Barracuda hybrids are a solid call — plenty of flow and built like tanks themselves. Closed loops are definitely the move with that thick acrylic, and adding true-union ball valves on each loop will make your life a lot easier later on. I’d also toss in small valves at each return nozzle — you’ll thank yourself when it’s time to fine-tune flow and get everything balanced just right.

Personally, I’d go with returns through the back wall. It keeps things cleaner, easier to reach for maintenance, and lets the aquascape really stand out. If you can hide the outlets just above or behind your rockwork, even better — that “invisible flow” look always gives a tank that pro touch. Matching nozzle color to the background will keep it extra tidy too.

Love the direction of your aquascape plan — a couple of islands with low rock piles is a great combo for both look and function. Tons of open space for coral to grow upward, great flow dynamics, and your note about fish behaving better with low cover is spot-on. You’ll get awesome movement up top while keeping everyone calm down below.

Taking your time and working through the details now is 100% the right call. Once spring hits and that tank moves inside, a build thread is gonna be a blast to follow. Definitely has the makings of a showpiece!

 

[mfinn]

On bottom closed loop returns use a 4 way tee and a 2 way tee stacked on top of each other for 4 directions with each return.

 

[Tonycass12]

On bottom closed loop returns use a 4 way tee and a 2 way tee stacked on top of each other for 4 directions with each return.

I think i would prefer to spread them out. Not a bad idea to stack them if more flow is needed in one spot but I dont mind drilling a handful more holes.

 

[Tonycass12]

So here is my plan so far. Figured I might as well go with some quality pumps and get some dolphin diamond aquasea pumps. They look to be really well made here is the USA and have some decent support. Not sure if I should go with the 9250gph or the 10500gph pump for the bottom closed loop. Just not sure if I would be short changing the flow slightly splitting it up between the 12 RFG nozzles with the 9250. The 9250 should be a great fit for the top closed loop with 9 returns. All the returns will be 3/4 RFG nozzles, im planning on doing dual RFG nozzles on the bottom closed loop. Returns for the closed loop will be on each side of the overflow with one side feeding the top closed loop and the other feeding the bottom. I may glue in some tabs so I can add a black acrylic grate to keep fish/snails from making it into the returns and keeping the back wall look a little less cluttered with bulkhead strainers sticking out of the closed loop returns. All in all if I only go with the 9250s the turnover rate not counting the return pump from the sump will be around over 61x the tank volume per hour. That should be more than enough for all the sps in plan on packing in here.

 

[adova]

Any chance you can post a picture of your tank? I am about to build one that size and am curious about some of the setup.

Did you buy it used? If new, from who?

 

[Tonycass12]

Any chance you can post a picture of your tank? I am about to build one that size and am curious about some of the setup.

Did you buy it used? If new, from who?

its currently trailered up until we have a lot of our snow melt. I purchased it used, was only set up for about a year by the previous owner. He told me it was built by advanced acrylics and was a little difficult for them to get the 10' sheets of 1" acrylic. Hopefully in a couple weeks with the warmer weather were starting to see in northern michigan I can get it into the garage and start buffing the interior of the tank. Once this thing gets put of the trailer ill be starting up a build thread.

 

[Tonycass12]

So here is my plan so far. Figured I might as well go with some quality pumps and get some dolphin diamond aquasea pumps. They look to be really well made here is the USA and have some decent support. Not sure if I should go with the 9250gph or the 10500gph pump for the bottom closed loop. Just not sure if I would be short changing the flow slightly splitting it up between the 12 RFG nozzles with the 9250. The 9250 should be a great fit for the top closed loop with 9 returns. All the returns will be 3/4 RFG nozzles, im planning on doing dual RFG nozzles on the bottom closed loop. Returns for the closed loop will be on each side of the overflow with one side feeding the top closed loop and the other feeding the bottom. I may glue in some tabs so I can add a black acrylic grate to keep fish/snails from making it into the returns and keeping the back wall look a little less cluttered with bulkhead strainers sticking out of the closed loop returns. All in all if I only go with the 9250s the turnover rate not counting the return pump from the sump will be around over 61x the tank volume per hour. That should be more than enough for all the sps in plan on packing in here.

Still interested in what some folks with any experience on these higher flow pumps and RFG nozzles have to say about my plan for flow.

 

[mpatterson42]

fragdaddyreef

LFS Founder - Hobbyist at Heart ðŸ 🪸 Custom 800g Glasscages Display 🌊

www.youtube.com

You might try reaching out to this guy, he built a very large aquarium with a lot of thought into closed loops. Basically he wants high flow but he doesn't want to have powerheads.

 

[WhatCouldGoWrong71]

I have 3 loops on my main display. In a couple months I’m building a man cave fish cave in my garage. This will host a 800g peninsula with 4 loops. Clearly I’m a big loop fan. If you go with loops, any holes drilled below the waterline I would only recommend using Hayward bulkheads. Also, proper install is important. No grease. Glass cleaned with alcohol and left to dry and degas. I would use thread thread, the bulk head itself is reverse thread. Than has a videos on the topic. Ensure you understand the opening size. They are much bigger than a standard bulkhead. Reefers who were using loops 20y ago will advocate against loop use. But, they were using the $4 bulk heads 20-25 years ago. I’ve broken those in overflow boxes. The thickness of the EPDM gasket alone is about as thick as the flange on a conventional bulkhead. My early posts on my build thread should have pictures.

 

[WhatCouldGoWrong71]

I thought 3 loops would do the same (less need for power heads). I guess I could have gotten away but as a tank grows, lower loops don’t move with the growth. You wind up having to drop lower heads in. Growth eventually becomes disruptive to flow (which is what you want). You just have to chase flow. I’ll tell you this. I’ll never do upper loops again only lower. The Orca has solved for that. My new tank has 14 holes all in the lower 1/3rd.

 

[mfinn]

I have 3 loops on my main display. In a couple months I’m building a man cave fish cave in my garage. This will host a 800g peninsula with 4 loops. Clearly I’m a big loop fan. If you go with loops, any holes drilled below the waterline I would only recommend using Hayward bulkheads. Also, proper install is important. No grease. Glass cleaned with alcohol and left to dry and degas. I would use thread thread, the bulk head itself is reverse thread. Than has a videos on the topic. Ensure you understand the opening size. They are much bigger than a standard bulkhead. Reefers who were using loops 20y ago will advocate against loop use. But, they were using the $4 bulk heads 20-25 years ago. I’ve broken those in overflow boxes. The thickness of the EPDM gasket alone is about as thick as the flange on a conventional bulkhead. My early posts on my build thread should have pictures.

What do you do for the suction side?
On the inside of the tank?
Do you keep them accessible for clean outs?


On mine I thought I left room, but over the years that room seemed to disappear.

Then reaching them from the front on a 30" wide tank is near impossible with them being 3/4" of the way down the back glass.

 

[WhatCouldGoWrong71]

I’ll be h

What do you do for the suction side?
On the inside of the tank?
Do you keep them accessible for clean outs?


On mine I thought I left room, but over the years that room seemed to disappear.

Then reaching them from the front on a 30" wide tank is near impossible with them being 3/4" of the way down the back glass

I’ll be home in an hour. I’ll shoot and upload a video. I’ll explain it on video. The do’s and don’ts of looping, lol. I’m gonna show you some “don’t do” methods! lol.

 

[Tonycass12]

I thought 3 loops would do the same (less need for power heads). I guess I could have gotten away but as a tank grows, lower loops don’t move with the growth. You wind up having to drop lower heads in. Growth eventually becomes disruptive to flow (which is what you want). You just have to chase flow. I’ll tell you this. I’ll never do upper loops again only lower. The Orca has solved for that. My new tank has 14 holes all in the lower 1/3rd.

Can you elaborate on this? Sounds like your saying the lower loops become ineffective over time with the corals growing out? I may be interpreting that incorrectly.

 

[Tonycass12]

The current plan for my system is to go with 2 dolphin 9250s. Each will supply 9- 1" RFG nozzles down each side of the top of the tank spaced 1' apart through the eurobrace. Returns for the closed loop will be in the upper half of the tank on each side of the overflow, 2 returns each for redundancy and i was thinking about building a wall with a removable acrylic strainer to keep any smaller fish away from the return strainers. Figured that would put more than enough flow into the 10' tank without needing to add to much.

Even though this plan will put 18 return nozzles across the top of the tank i figured it will give me a generous amount of water movement for all the sps.