Backyard Aquaponics
A place to discuss aquaponics

Have you ever bought half a saw TC

Hi all!

I have read through this whole thread. I think that the general consensus is that the no-hole overflow is not reliable due to the eventual build up of air in the upper part of the upside down "U". However I have an aquarium for an aquaponics system that I am trying to setup that I do not want to drill so was think "Is there a way to make the no-hole overflow easier to maintain and make it longer between failures?"

I think that there is. Here is my idea.



If a tee was added to the top of the upside down "U" and two valves and a piece of clear tubing in between the valves this would create a sight glass and a place to store the air that gets into the overflow. Maintenance would be a simple matter of closing the bottom valve, opening the top valve and then adding water to the sight glass with a funnel. Then closing the top valve and re-opening the bottom valve would replenish the storage area for air.

If my theory on this is right then the bigger the sight glass (also the unwanted air storage area) the longer between failures. I think that using normal ball valves for this you should not have a problem with valves causing the failure like with the duckbill non-return valve.

OK, so now I would like some comments on this idea as to whether on not you think this will make a no-holes overflow more feasible for an overflow drain on tanks like aquariums that you really don't want to drill an overflow hole.

Greetings,

Frederick

Absolutely. I've run a few like this and they work great.

Biggest failure point is if you have an aquarium aerator and the fish push it to a place where bubbles get sucked into the trap and break the siphon. This can happen in hours.

PS: nice first post!

I made a water bridge for my tank with a siphon on top of the bridge. I sort of discovered it by mistake. I wanted a way to suck the air out of the bridge to get it started so I put a small tube in the top of the bridge. When I sucked the air out (fish water tastes yucky!), it started to siphon. I was planning on putting a small valve at the top of the bridge, but instead I just stuck the tube down the standpipe. It's been running for about 2 months without a single problem.

One problem you can run into is that you loose power and it will continue to slowly siphon. If too much water siphons out of the system the pipes in the water bridge will let air in and break the bridge. You should put a safety float into the system if the water level gets too low.

Below is a diagram of the setup and a pic of mine in operation.



NOTE: The white pipe inside the tank is connected to the black above the water line. The camera angle make it look like they aren't even close!

Interesting. So the white pipe is an uncontrolled siphon that runs far slower than the water flowing into the tank, right? All it needs to do is have a small enough diameter to allow bubbles to block it completely so they get pulled down as a plug rather than depending on flow rate to do the job.

You could even have it run to a reservoir a few inches (several cm) lower than inside water level to limit the amount that it can suck out of the aquarium in a power failure.

Only possible failure point I see is biofilm blockage, but one could schedule something.

Just butting in here to say thanks TCLynx.
I have been stressing about overflow as I am sure West Aus will be getting rain shortly! Great info here for what I need cos dont want fish over the sides of tank. I am learning all the time

I wonder what would happen if you moved the siphon line to the fish tank? or into the container outside the tank where the other siphon goes? I wonder if the smaller tubing would still siphon off the air bubbles or if it would break the whole system when air gets into it?

My my knowledge of hydraulics theory is a bit thin, but I am wondering if the smaller size of the pip would make some magical difference.

One other question: Shouldn't your water level in the tank and the reservoir outside the tank be the same in a no-holes overflow? In your diagram they are quite different.

Well, in any case you have the system to test I still need to build mine.

Thanks again for your help and comments!

Frederick

Hi hydophillia!

Thanks for the post I was wondering if you could post a picture of your setup from the Tee up. I can see part of it in this picture in the upper left, but I would like to see more.

Thanks!

Frederick

The siphon line has to go into the drain....the exit must be lower than the water level in order for it to siphon....otherwise the air would go in through the exit and break the bridge's siphon.

If there was no water going into the tank, the water level between the tank and the stand pipe container will be equal. Once the fish tank starts to fill, the level will rise in it as the water drains through the bridge. On my system, it will raise about an inch (draining through a 1" bridge pipe)

Frederick,

The water outside the aquarium will be lower than that inside when water is running, but if the pipe is large enough the difference will be very small. When power goes off, fish tank will drain to level of outside level.

The small air-sucking pipe needs to siphon to an even lower level than the average of fish tank and outside level, but I don't know the minimum it would require: 1cm? 5cm?

Here is a pic of my indoor no-holes overflow. I used as much plumbing as I could find that I already had on hand. For newer ones I have used PVC shutoffs rather than a hose bib. Sorry about the confusion of pipes: the thin stuff is coming from the sump and growbed outdoors. The side arm covered with algae is inside the aquarium: in case the bottom inlet gets clogged, water rises and goes out through that secondary arm (without bringing in bubbles, one hopes!). Paint job is by the DW.

The other pic is two no-frills no-holes overflows in an outdoor system: water flows from trout tank to settling talk to catfish isolation tank (under the boards) (they were killing the trout), then is pumped back into main tank. If I pumped into this system I could overflow it. As it is, I can only run the pump dry. I've had the overflow clogged by a dead trout a few times, so clogging is something that certainly can happen.

just made a 40mm No Holes SLO Over Flow, just cant get it to prime despite how much water i throw into it it can handle it and not push the air lock out... any ideas???

Runs Right to the bottom of 1 barrell and then bout 200mm into the next one so its bout 100mm below my SLO to the growbeds, it will never get below the pipe, this way, just gotta get the bloody thing primed.....

Got it by putting a cap on the short end, filling it up and quickly sticking it in, the removing the cap my tanks leveled in seconds! Can now low much more flow into my ft from sump now!!!!

Just wondering if anyone has had troubles over time with No Holes Bridges.

Mine has been running Flawlessly for a day n a half im happy with its operation and it does everything i need.

i am making my tank stand up this week and im going to use no holes Bridges between my tanks, then i can make it a flat base with no need to lift my tanks 100mm higher than eachother if i was going to do it with bulkheads and SLO's. NoHoles SLO Bridges makes it all easier to build, insulate, clad and Lid.

i will get some propper brackets for holding 40mm pipe and attach them all very ridgid, and also glue the joins with propper glue instead of silicone other than air bubbles entering the pipe over time from my Airstones there should be no other reason for it to fail??

was also going to install some 20mm bulkheads into the tops of every tank and link them all up and return to the sump that way if anything fails it will just cycle back to my sump at any point until i come across it and fix it (better than emptying my sump, overflowing my tanks and running my pump dry)

i think i have all bases covered, any ideas will be awesome )

a note on how my tanks will be linked, as seen in my photos, i will have an Entry tank (where my pump enters) then make a SLO pipe from the bottom running up and over the top of the tank and back into the next tank about 100mm below water level (a bridge) then from that tank same thing again between my next 2 tanks then iv got a bulkhead SLO in my last tank that feeds out too my Growbeds, this way i can build my tank stand to hold 4 x 200l Barrells and just run my two for the minute and add more in as my system grows or as i get barrells easily.

i think this system should cycle all the water between the tanks will put 90D Elbows on the end of my Bridge entry points to create a natural whirlpool effect.

also does anyone have any comments on running the 200l Barrells in a modular setup as for the fish's well being?? im not interested in over stocking my system.

Picture of my SLO No Holes Bridge



Test Run of modular system

I like your overflow back to sump. Good idea.

I've found that the no-holes-overflows WILL build up bubbles in the loop and eventually fail. I'm not sure where the bubbles come from (I have several hypotheses, but they don't give a good path to a solution), but the simplest way to increase time between failures is to have a collection reservoir as in my pics above. You could get away without a valve, but I like it so I can reset everything every month or so and clear any bubbles.

To err on the side of caution, you may just want to regularly reset the overflow manually once per month/week (and not get lazy about it).