Connect Two Tanks

[DCR]

If you bulkhead two tanks together the hydraulics works as if it was one tank. Put the overflow in the 95. The height of this will set the water level in both tanks. Ensure the bulkhead between the two will handle all the flow coming into the 200. It is really pretty simple.
The height of the bulkhead in irrelevant as long as it is completely submerged. Screen if you are concerned about livestock migrating between the 2. Keep in mind screening will reduce possible flow.

True, there will be some negligible difference if the bulk heads are large enough, but then you will have no surface skimming on the main display tank which I consider a non-starter.

 

[maroun.c]

I have 7 tanks all.connected together, mostly by overflowing into one sump. One of them is at same height of sump and had to con ect it by drilling. Gravity is a different dynamic and a 1.25" hole.qnd plumbing just below water level wasn't enough as water has to rise above it to build up pressure to drain as there's little gravity forcing the move I could barely move 5000 G per hour before water was too high. As I needed much more flow ended up drilling another hole in both tanks a bit above bottom and can now run 1500 gph. Problem is lack.of surface skimming which I worked around by adding an overflow in the tank before the holes so basically water overflows into a partition that has the holes. Had to make it a large enough partition somwater level was stable.

 

[Soren]

I’m planning something similar, but the display ‘fuge is mid height, vertically, between DT and sump. I’m also going to add some T’s and ball valves so I can adjust the plumbing later without too much hassle.

For two tanks at the same height, seems best to plumb both into sump.

This sounds very similar to my build in layout!

So what I'm getting from this discussion is that I should drop the 95g down about a foot, and leave the space above it largely open for mangroves. ;)

Yes, that will make it much the same layout as my build, albeit noticeably larger!

The drain is in the second tank....water always find equilibrium so yes they will remain roughly the same height....it does this because water flows between tanks . If the theory is it wont flow between tanks because the height is the same then there is a logic problem. They only stay the same height because water flows between them.

I see what you are saying here. As long as the return goes into the 200 and the drain to sump is in the 95 (as was mentioned as the plan), there should still be flow between the tanks. My point was not clear, as I did not mean there would be no flow between tanks (this is a must, as you stated) but rather that there would be little surface flow (though I suppose this depends on a lot of factors). What I am still trying to understand is if it makes a difference on where the water comes from. For example, will the surface skimming be much less with the tanks at the same height since the flow will go through the bulkheads mostly below the surface? If the system layout is being designed for the purpose of pre-filtering in the 95 with macroalgae/mangroves, will this limit the nutrient transfer or not? I have no experience with this yet, but it is a consideration on my own setup (though mine has a height difference). Essentially, what I am trying to determine is if there is a difference in nutrient transfer if the tanks are plumbed circularly instead of plumbing both tanks separately to a common sump? The reason I planned mine circularly was to give the chance for food and detritus to settle in the mangrove lagoon some before the sump in order to be taken up by the mangroves. Maybe there is no significant difference. I appreciate this discussion and your input, since it also directly relates to my build plan while I am still at a stage that I could make changes easily if advisable.

 

[unchaotic]

If you bulkhead two tanks together the hydraulics works as if it was one tank. Put the overflow in the 95. The height of this will set the water level in both tanks. Ensure the bulkhead between the two will handle all the flow coming into the 200. It is really pretty simple.
The height of the bulkhead in irrelevant as long as it is completely submerged. Screen if you are concerned about livestock migrating between the 2. Keep in mind screening will reduce possible flow.

I have 7 tanks all.connected together, mostly by overflowing into one sump. One of them is at same height of sump and had to con ect it by drilling. Gravity is a different dynamic and a 1.25" hole.qnd plumbing just below water level wasn't enough as water has to rise above it to build up pressure to drain as there's little gravity forcing the move I could barely move 5000 G per hour before water was too high. As I needed much more flow ended up drilling another hole in both tanks a bit above bottom and can now run 1500 gph. Problem is lack.of surface skimming which I worked around by adding an overflow in the tank before the holes so basically water overflows into a partition that has the holes. Had to make it a large enough partition somwater level was stable.

I think these guys have got it according to the info on this webpage: Connecting Water Tanks

The bulkheads can actually be near the bottom, the lowest overflow decides the water level for both tanks, and a weir system before the bulkheads could be used to provide surface skimming. I might get a hold of a couple smaller tanks just to give it a try.

 

[mdb_talon]

In your situation i would put a wier overflow in the DT. The bulkhead inside the wier near the middle depth of the tank. You get surface skimming that way with nutrients going into the 90g before sump. The problem i see with that setup is possible noise inside that wier with the waterfall. I had something similar setup to that years ago gor freshwater and i solved the majority of noise issue putting filter floss in the overflow....but that would largely negate your reason for doing this.

 

[unchaotic]

Here's another concept for this goal. I'm not necessarily planning to do this but I always love considering as many options as possible.

What about adding a closed loop system onto the 200g and having half of its output feeding the 95g tank? Depending on the CL pump size, that could provide the majority of the flow for the refugium. I would still have wiers and overflows on each tank to take the water to the sump.

I'm just discovering closed loops so I would understand if is a half-baked idea. Do the inputs for the CL need to be drilled on the bottom or can they be on the back glass?

 

[mdb_talon]

The inputs can certainly be on the back glass. Just ensure the overflows in each tank are capable of draining the fulll volume coming from the sump (without the CL redirecting some of the volume) in case your CL pump fails, but return pumps keep running.

 

[DCR]

The problem will be if the CL flow to the refugium exceeds the return flow to the display. Then you will empty the display and likely flood your sump (unless really oversized). The same thing will happen if you lose the return pump and CL continues to flow from the display to the refugium. I would not recommend doing it. Keep it simple.

 

[unchaotic]

The same thing will happen if you lose the return pump and CL continues to flow from the display to the refugium.

That makes sense. Who would have thought that "opening" a closed system could have dangerous consequences, lol.

 

[Soren]

Here's another concept for this goal. I'm not necessarily planning to do this but I always love considering as many options as possible.

What about adding a closed loop system onto the 200g and having half of its output feeding the 95g tank? Depending on the CL pump size, that could provide the majority of the flow for the refugium. I would still have wiers and overflows on each tank to take the water to the sump.

I'm just discovering closed loops so I would understand if is a half-baked idea. Do the inputs for the CL need to be drilled on the bottom or can they be on the back glass?

I don't want to derail your topic, but can you suggest good threads or sites for researching closed loops? I have heard of them but do not really know what a closed loop is exactly. What differentiates it from a typical display overflow to sump with a return pump?

 

[unchaotic]

I don't want to derail your topic, but can you suggest good threads or sites for researching closed loops? I have heard of them but do not really know what a closed loop is exactly. What differentiates it from a typical display overflow to sump with a return pump?

I think I first ran into it with HuduVudu's Build. His goals included avoiding powerheads (heat production and aesthetics) and to have massive flow. So on his build (and in most of them I believe) the closed loop was in addition to the standard system with a sump.

 

[Soren]

I think I first ran into it with HuduVudu's Build. His goals included avoiding powerheads (heat production and aesthetics) and to have massive flow. So on his build (and in most of them I believe) the closed loop was in addition to the standard system with a sump.

Thanks! I think I finally understand the difference after a bit more research on aquarium closed loop plumbing.