Making a Tank-to-Tank overflow?

[Alexraptor]

I have a little setup with two 10 gallon tanks side by side.

The one being my little mandarins tank.

Things are just perfect with her, but I wanted to expan the system so I could create a nice safe haven where pods can live in piece.... and possibly with a Mantis in the future.

 

My thought was to start with removing the light fixture supports and using its built-in hooks to suspend it from the cieling.

Next, I want to elevate the tank on the right a bit, so that I can set up an overflow from that tank into the mandarins tank, so that reproducing pods can get in unmolested.

 

Question is, which is the best way to achieve it?

Should one drill a couple of overflow/drainage holes near the top? And if so, what size and how high up?

Or could one perhaps cut out a notch in the top of the tank and sort of create an overhang that drains into the second tank?

Or might it work to simply just hook up an overflow box?(not really sure on how much height differential there needs to be for the siphon to work)

 

Thoughts?

[xmas_one]

Why not just make the pod tank your sump and put it beneath the mandarin tank?

[Alexraptor]

1.) I don't have room for a sump.

2.) I don't want to.

[N.Radd]

Just a question: if tank 1 overflows into tank 2, will you set up a system that will drain water from 2 and return it to 1? Could be a cool build.

[Mpy]

Since you would have to drain the other tank to raise it anyway, it would be best to drill the side and have a bulkhead that would drain into the mandarin tank, but it is very easy to break a 10g... You would need a pump in the mandarin tank to supply water to the other, but it would keep the pods from getting chopped up.

 

By drilling you wouldn't have to deal with a siphon(so long as your hole&bulkhead is big enough) and the refug tank wouldn't need to be raised up as high as for a commercial overflow siphon box. Trying to notch a glass 10g tank would likely end in a broken tank is my guess, and then you would need to create a spout to get the water to flow into the mandarin 10g.

 

Siphons work based off of height differences. the higher the water level is vs the opening of the siphon the higher the flow.

[Alexraptor]

So drilling is the best option then.

 

Another thought that cropped up was perhaps trying a water Bridge, but not sure how they work with actually exchanging water, or if they would simply just provide a means for pods to migrate from one tank to another.

[Alexraptor]

Ok I am giving real serious consideration to a water bridge type setup.

Set up a little mock up with spare parts that seems to work just like a charm.

 

Red bucket pumps water into green bucket that flows back into red bucket.

Will probally set up an array of pipes to minimise the risk of siphon breakage and overflowing, and also install checkvalves to allow for the easy restarting of the siphon after doing water changes.

 

Of course, it seems too good to be true so theres probally something really scary about this that i'm missing.

What risks am i not thinking about?

[Mpy]

the problem with that method is that the water height (thus pressure)difference between the two tanks will be minimal so the water bridge, which is just a siphon, will not have very much flow. Check valves require more pressure that the siphon will generate in this system so I don't see them really working for you.

You need to determine what amount of flow you want between the two tanks, and that will help to determine the flow rate needed. If youre only having like 20gph then the waterbridge should work no problem, but if you want 100gph its probably not effective enough.

[tibbsy07]

You could always put an overflow box on the right tank, have it drain to the lower mandy tank and then put a simple pump to pump water back up into the upper tank, using rigid tubing and some loc line.

[Alexraptor]

the problem with that method is that the water height (thus pressure)difference between the two tanks will be minimal so the water bridge, which is just a siphon, will not have very much flow. Check valves require more pressure that the siphon will generate in this system so I don't see them really working for you.

You need to determine what amount of flow you want between the two tanks, and that will help to determine the flow rate needed. If youre only having like 20gph then the waterbridge should work no problem, but if you want 100gph its probably not effective enough.

The check valves i'm talking about are small ones to easily remove air from the tubing when starting/re-starting siphons between water changes, etc.

And since i have dedicated pumps in each tank i don't need very high flow through the water bridge.

It mainly needs to serve as a conduit for pods and other microfauna and to somewhat equalize water parameters between tanks.

 

Not quite sure if one should use solid color or transparent PVC.

The former prevents algae growth, but the later allows for easy inspection to check for potential air buildup.

[Mpy]

ah, my bad, I was thinking check valves on the siphon itself... what you could do instead of a check valve(which can still fail) is attach an airline from the top of the siphon tube to a venture on the pump used to move the water from tank to tank. that will keep the siphons established and automatically restart them should they fail.

[Nocturnal]

ah, my bad, I was thinking check valves on the siphon itself... what you could do instead of a check valve(which can still fail) is attach an airline from the top of the siphon tube to a venture on the pump used to move the water from tank to tank. that will keep the siphons established and automatically restart them should they fail.

 

Or hook up something like an aqualifter to the siphon. I've always had back luck with the built in pump venturis.

 

Water bridges don't seem to allow much flow. I had two drilled tanks whose overflows I connected in that manner and I was shocked by how slow the water drained back into tank 1.

[GHill762]

connect the two tanks with a bulkhead or two (no overflow, just a bulkhead, maybe a screen/drain cover over the openings), then to increase flow between the tanks pump from one tank to the other.. simple and shouldn't ever overflow..

 

you don't want to try and rely on siphon for level tanks, and you don't want an overflow.. just a hole in both tanks, such as a bulkhead in each, allowing water to freely pass between the tanks as if they are one.

[seabass]

How about just using a 20L instead. You could put in a baffle to separate the two sections.

[Alexraptor]

just a hole in both tanks, such as a bulkhead in each, allowing water to freely pass between the tanks as if they are one.

Not an option.

Would involve draining and emptying out the mandarins tank.

 

How about just using a 20L instead. You could put in a baffle to separate the two sections.

Not an option.

Simply cannot afford buying a new aquarium at this time.

[seabass]

A 20L isn't very pricey, but OK.

 

You could try and notch the two tanks and silicone a spillway between them.

[hey]

yeah a baffled 20long would cost 20$ + 10$ for the glass baffle and 5$ for the silicone. I could easily seeing this water bridge set up costing more than 35$ in parts. Have you priced any check valves they aren't cheap in the least.

[Alexraptor]

Unfortuantely aquariums are nowhere near that cheap here in sweden.

Just a small 10gal is more than $60

 

On top of which I am simply just not going to tear down a healthy and mature pod producing tank.

[GTi]

How about as part of your daily maintenance'feeding you scoop a couple of cupsful out of one and in to the other tank? Not very elegant but zero cost and no risk of breaking the tank. Interesting project!

[GHill762]

or transfer pod condos back and forth..

[Alexraptor]

Honestly, have yet to see a compelling argument against water bridges.

 

Sure things could get nasty of the siphon fails, which is why i plan to do it with redundancy in mind, i.e multiple smaller bridges, each being sized to handle whatever flow rate I want.

And its unlikely that 3-4 pipes would fail simultaneously.

 

And the mock-up seems to work really well.

They may not produce much current, but they definitely produce flow in direct proportion to the capabilities of the pump.

Which with my mock-up is over 200gph.

And I mean if the pipes were not accomodating that flow, then things would be overflowing

[straydog]

If you are just trying to join the two tanks together why not install a hob filter on each tank and bulkhead the two together . The water will flow from one filter to the other , use clear tuning with a light above it to entice the pods to go towards the pipe. The tanks being on the same level should keep a constant water level even if one of them is not running (meanin that if one hob is not running the other tank wont overflow) would only take a couple of 1/2 inch bulkheads to connect the two hob filters.

[seabass]

Honestly, have yet to see a compelling argument against water bridges.

Well, there is always a risk of floods when using over the rim siphons. However, it will work. And like you said, redundancy will help reduce the risk of overflows.

 

Some are a little more elaborate.

 

I'd recommend a dosing pump like Tom Aquatics Aqua-Lifter to prime help keep air out of the overflow. Here's a video of CPR's overflow which might give you ideas:

[farkwar]

If the mandarin swims through the bridge over to the pod tank, whats the difference then from just having one tank?

 

Or bulkhead between the two tanks, same issue.

[seabass]

If the mandarin swims through the bridge over to the pod tank, whats the difference then from just having one tank? Or bulkhead between the two tanks, same issue.

Good point. You'd need a prefilter (like in the first pic I posted) or a intake screen.

 

However, with all the: plumbing, screens, risk of overflow, dosing pump, algae build up, etc, you'd probably be better off with a single tank. I'd just save up for one instead of messing around with all this and switching to better solution (single tank) down the road.