Two Tanks One Pump (DIY fail-safe aquarium overflow system) 

yes it is a siphon, the levels of the left and right side piple does not matter as long as they are flooded and below the water level.

Glad the video was of help. Adding in a float switch (after I made the video) was definitely a good idea as there was more than one occasion that it turned off the pump and prevented overflow of the top tank.

Thanks

Thanks so much for the kind words. Glad the design helped you out.

@@robertdotfox Hi Rob, just quick question. The blue intake pipe (the end that is in the aquarium), has got a sponge on the end of it (stop fry from getting sucked in). Is that all that you've got at that end or is there anything else besides that as well.

@@khaldrogo8559 Just a sponge. You don’t want to inhibit the flow of water too much as it’s only gravity fed.

Yep, you got it. Since it’s all run on one pump, adjusting the flow rate from the lower tank (with the black valve) automatically adjusts the rate of the overflow too. The faster water comes in, the faster it leaves. I was born in the UK, have lived in the states for 9 years, and currently live in Thailand 😉

You’re welcome. I’m using a food grade plastic container for the overflow box.

Is the lip it hands on just acrylic and superglue? Or silicone?

@@davidwatson7364 Not sure what kind of plastic it is. I bought two of the containers and cut one up to make the hook onto the tank and the lip the water bridge rests on. Superglue.

You’re welcome.

Thanks. I’ll look into attaching an air pump.

@@robertdotfox Good luck! I never tried this myself, but there is a lot about this on RU-vid. Do some research first. I think not all air pumps are suitable. The noise might be irritating. It would irritate me for sure. I have used floatsting switches though, and they work fine. You place them in some unconspicuous place and use them to shut down the power head or to start the air pump. Might be easier to use on the air pump actually, since you can ge DC airpumps. AC is more dangerous to use if you don't know what you are doing. The switch costs a few dollars and you need a relay (AC or DC) for below 10 USD.

@UC3iaCXnV_URbekrnFBaTPXw I think Laurent is saying that if the blue U-bend pipe get air in it (or the attached filter gets blocked - more likely in my opinion), then water will not be able to flow out of the fish tank, but water will still be pumped into the top filter and fall into the fish tank. So if water keeps flowing in, but can’t flow out, it could flood. It hasn’t happened yet, but it is possible. I’m not looking to attach an air pump anymore, but have ordered a float switch to turn off the pump in the event of the water level in the main fish tank gets too high. Thanks for your comment and kind words.

@@robertdotfox that's right Rob. I could not believe air pocket would just form spontaneously, but it did. I am actually building a little arduino system to control the floater, the light and the CO2 diffuser. Lots of fun!

@@laurentdrozin812 Nice! I’d love to see your set up.

I’ve since added a float switch on the top tank that controls the pump in the lower tank - so if the top tank gets too full, the pump switches off. Perhaps I’ll make a video with the new inclusion.

@@robertdotfox 👍nice work!

I added a float switch to the top tank after I made the video. If the top tank gets too full, the pump shuts off automatically.

Yes, the water would still circulate, but you’d need filtration somehow.

@@robertdotfox i think it is the simplest and best overflow system I’ve ever seen! I was thinking about drilling a hole but this is a risky operation. I want to install a drip water change system with an overflow. I think I am going to try with your system. Thank you very much for this excellent video.

No, sorry. I went to local shops near where I was living in Thailand.

I added a float switch to the top tank after I made the video. If the top tank gets too full, the pump shuts off automatically.

Because it’s not a siphon. As long as there is no air in the blue U-shaped pipe, it will only equalize the water level in the top main tank and the little side overflow box. Once those levels are equal, water will not flow. The way to make the water flow continuously is to constantly pump water into the top main tank, then the water will flow through the blue U-shaped pipe and out of the overflow box.

@@robertdotfox thankyou so much!

Which part would you like me to explain? It’s really a very simple design that should be clear from looking at it. The blue pvc pipe is free floating with the filter end in the tank and the outlet in the small overflow box.

How did you make the overflow box

@@simonsmith7594 I bought a food grade little plastic storage box from the supermarket, drilled and siliconed in the white pipe. I then heated and bent another piece of plastic into a U shape to hook over the side of the aquarium and glued the box to it.

You’re right. I modified it with a float switch that kills power to the pump if the top tank gets full. - see description

Your local hardware store? Home Depot? I don’t know where you live. I’m in Thailand.

@@robertdotfox ok figures, I’m in the states and have not been able to find tubing like that. Thanks for the response

I made it myself.

I bought a small plastic container from the supermarket, then superglued another piece of plastic to it and heated and bent that piece to hook onto the tank.

No problem. You could use this same idea with any size tank.

Thanks You so much for inputs.

I was trying to stack 2 tanks vertically and circulate water between them. Mission accomplished 😎

It’s actually not. It’s a water bridge to an overflow. A siphon sucks water, this system cycles water at the rate water is pumped and overflows.

Not sure that I understand you correctly, but there are no problems with this design in a power outage as demonstrated when I turned the pump off in the video.