Best Practice for water flow in split tank?

[ichthyogeek]

So I'm a very industrious aquarist...but I'm a very lazy plumber. I'm planning out a potential top-down system, but I'm conflicted on how to do plumbing. It'll ideally be a three tier system, with one tank on top (20L) divided in two using a DIY craft mesh divider, draining to two tanks in the middle, which individually drain to the sump. Then a pump will push water back to the top tank. The idea for the top tank, is that it will have two DIY overflows on the sides of the tank (no drilling), and the water when pumped will split once it reaches the top tank.

What has me confused, is how I should distribute this flow throughout the tank. The top tank is a planned macroalgae tank on both sides (one side holding banggai cardinalfish, the other holding mollies). I'm thinking that plumbing should be single and then split once it reaches the top tank, as opposed to splitting earlier on. My question is: what's the best way to distribute the flow plumbing wise? Assuming that the overflows are at the frontmost corners of the tank, the tank is split in two, and that the water comes out from the middle of the back part of the tank, I'm conflicted if I should use a tee or a "side outlet elbow" to initially split the water, and if I should use 90 or 45 degree elbows to aim the flow. I'm thinking that ideally the water should be forced down somehow, and then flow along the bottom of the tank, then rise up to exit from the overflows.

 

[Flippers4pups]

So I'm a very industrious aquarist...but I'm a very lazy plumber. I'm planning out a potential top-down system, but I'm conflicted on how to do plumbing. It'll ideally be a three tier system, with one tank on top (20L) divided in two using a DIY craft mesh divider, draining to two tanks in the middle, which individually drain to the sump. Then a pump will push water back to the top tank. The idea for the top tank, is that it will have two DIY overflows on the sides of the tank (no drilling), and the water when pumped will split once it reaches the top tank.

What has me confused, is how I should distribute this flow throughout the tank. The top tank is a planned macroalgae tank on both sides (one side holding banggai cardinalfish, the other holding mollies). I'm thinking that plumbing should be single and then split once it reaches the top tank, as opposed to splitting earlier on. My question is: what's the best way to distribute the flow plumbing wise? Assuming that the overflows are at the frontmost corners of the tank, the tank is split in two, and that the water comes out from the middle of the back part of the tank, I'm conflicted if I should use a tee or a "side outlet elbow" to initially split the water, and if I should use 90 or 45 degree elbows to aim the flow. I'm thinking that ideally the water should be forced down somehow, and then flow along the bottom of the tank, then rise up to exit from the overflows.

Can you sketch a diagram of your idea and post a picture of it here to better understand what your proposing?

 

[ichthyogeek]

So it’s a little something like this, the main thing to pay attention to is the middle rectangle, as that’s a top down view of what I’d like the aquarium to look like (overflows at the foremost part of the tank, input at the middle). There’s also a few rough pipe sketches as well.

 

[laverda]

I think having four add on overflows outside the tanks is asking for trouble. I would definatly drillthe tanks for the drains if I was going to do this. I had 3 shallow tanks stacked on top of each other with a single feed and drain in each one. The drains were a single bulkhead with a 90 degree street elbow angling up with a large screen so the could not get obstructed. By rotating it a bit I could adjust the water level. They were oversized so they were quite and could handle double the output of the feed pump I was using. Then the bulkhead had another street elbow some straight PVC a 45 and another straight PVC going to opposite end the tank below. The second tank was the same.

For your setup I would have one drain in the center of each tank split it with wyes so it feeds the lower tanks evenly. You really do not want valves to control the flow as it could cause issues with drains set up like this. Feed both tanks from the two opposite corners. Angling the drain lines will help keep things quite.

 

[ichthyogeek]

I think having four add on overflows outside the tanks is asking for trouble. I would definatly drillthe tanks for the drains if I was going to do this. I had 3 shallow tanks stacked on top of each other with a single feed and drain in each one. The drains were a single bulkhead with a 90 degree street elbow angling up with a large screen so the could not get obstructed. By rotating it a bit I could adjust the water level. They were oversized so they were quite and could handle double the output of the feed pump I was using. Then the bulkhead had another street elbow some straight PVC a 45 and another straight PVC going to opposite end the tank below. The second tank was the same.

For your setup I would have one drain in the center of each tank split it with wyes so it feeds the lower tanks evenly. You really do not want valves to control the flow as it could cause issues with drains set up like this. Feed both tanks from the two opposite corners. Angling the drain lines will help keep things quite.

So I’m not sure what a wyes is, but I think there may have been some confusion, and a lack of info that I forgot to give. I redid the sketch and clearly labelled where I wanted to put the overflows on the top tank, as well as what I was initially aiming for. Luckily, the middle tanks came predrilled. But I don’t trust myself to drill anything, hence why I’m going with the cheapo pvc overflows and not drilling a bulkhead. The “X” in the sketch is what I’ve been having trouble with initially, but @laverda, did I interpret whst you told me correctly in the bottom part of the picture?

 

[laverda]

So I’m not sure what a wyes is, but I think there may have been some confusion, and a lack of info that I forgot to give. I redid the sketch and clearly labelled where I wanted to put the overflows on the top tank, as well as what I was initially aiming for. Luckily, the middle tanks came predrilled. But I don’t trust myself to drill anything, hence why I’m going with the cheapo pvc overflows and not drilling a bulkhead. The “X” in the sketch is what I’ve been having trouble with initially, but @laverda, did I interpret whst you told me correctly in the bottom part of the picture?

wye = Y as opposed to a T. Themiddle tank would do the same down to the lower tank. I would really try to avaid the over the top overflows if possible.

 

[ichthyogeek]

wye = Y as opposed to a T. Themiddle tank would do the same down to the lower tank. I would really try to avaid the over the top overflows if possible.

Ah, I see. I know there's risks involved with over the top overflows, but that's what I'm limited to. I would have figured that two overflows would be better than one, especially since the top tank will have macroalgae that might clog it if not maintained correctly. I'm still in the rough planning stages, so this is good to know, especially if I can get my hands on a drilled tank. I guess my big question is, if there was only one way to add water into the aquarium and two overflows, how best would I construct the plumbing in order to get a gyre-like flow (input->bottom of tank->overflow)? Mostly I'm focusing on the input into the tank and how to get the right flow pattern.

 

[Smarkow]

Having flooded a few floors with poorly attended to siphons... over the top flow terrify me :/

Good luck, keep us posted!!!

 

[laverda]

Then just do the opposite of what I suggested. Have the water enter the tank in the center splitting just before doing so and direct the flow down and along the longest side.