Backyard Aquaponics
A place to discuss aquaponics

I didn`t notice much fluctuation in the level although i was using a much longer drop configuration with perhaps 4.5ft from the top of the tank to the floor, so that may have had an effect. A piece of fine mesh over the inlet would probably keep the fry safe.

Ok... :-) Elbow at top removed and existing filter dropped over top of the pipe. Seems to be working now. I'm guessing the problems I had earlier with an upward facing intake were related to having the outlet too high.

My outlet is just over a pipewidth lower than the intake. That seems to work well.

Victoria,

Here's what I have on system 2.5.

The tall tube with the hose bib allows me to connect a hose and suck out air. I made the tube tall to allow the inevitable bubble to have more space since it should not cause problems until it reaches down to somewhere in the top loop.

The open tube outside the tank stops the outflow from siphoning.

I have my inflow down to the tank bottom to suck up solids. The tank level should sit just above or at the outflow level.

I've found I have a lot of bacterial buildup in the tubes and need to flush weekly. Maybe I should have used larger pvc.

I like your fish/debris strainer.

Have fun!

I spent a good month years ago, trying to do what you are doing with PVC pipe fittings. When I could get them to work, they would fail without warning because
of the bubbles building up in the syphon.

I had a bit of clear acrylic lying around so I decided to have a play around. I went through a few prototypes and finally found a very simple winning design.

Basically a clear box sits on either side of the aquarium glass. Another piece of acrylic joins the two and when the ends are closed off it creates a path for
a siphon to be created.

To start the syphon water is poured in either side and a piece of clear airline tubing is used to suck the air out of the top to create the syphon. When the water in the
tank drops below the lip of the internal section, flow stops but the siphon remains. Periodically I have to remove air bubbles that build up in the overflow box,
which are clearly visible through the clear plastic. By making the overflow box large enough, the water flow is never really restricted.

I have 6 of these in use at home on my main tank, the marine tank and an the breeding tanks, which are pictured below. The pictures show parts of a 3 tank chain
which has been plumbed to a sump for greater filtration.

My latest one, notice the bubbles. The smaller bubbles are a problem in marine tanks, but as they combine you can remove them using a piece of airline tubing. (Use a long piece, so you don't get a mouthful of salt water...)

The second picture shows a sump and monster protein skimmer I recently installed on my brothers marine tank.

Tim, your pic is the one I remember seeing first and what started me down this particular journey. We have lots of PVC parts around and were trying to avoid the purchase of an actual overflow box. I know you made yours but we also don't have acrylic lying around.

Hydrophilia, inside the tank, do you have an intake at the bottom and the opening at the "HSM" level?

Also, the loop top bubble remover, what are you using? I like Hex's idea because it doesn't require human intervention but we don't have a venturi. We do occasionally leave for a few days and it would be nice to have this be fail-proof since it sits in our living room.

For the moment, what we have is working beautifully along with the loop siphon I've been battling as well. But, I do believe in planning for disaster as it seems to prevent disaster.

BTW, I've been reading this forum for months and I have a general idea what HSM is but what the heck does it stand for?

Tim,
Likewise, your design was the model for mine. Very nice and clean, I am far more comfortable with PVC and do not have the tools or expertise to fabricate acrylic or polycarbonate. I did buy a piece of polycarbonate tube for the air trap so I could see if there is any air in there before it causes trouble.

Victoria,
HSM="holy s*** mode". See also .

My main intake is at tank bottom or an inch above it. My HSM intake is above the normal tank level and takes over if the main intake is clogged and the water rises to that level. I find water levels fluctuate as intake clogs or as bacterial slime builds up inside plumbing or bubbles build up in loop.

I really like TimC's clear plumbing as you can see bubbles building up, but like pvc for other reasons.

My idea on bubbles is that we always get small bubbles and these are not a problem until they fill the top of the loop above the aquarium edge (more complex than that, but I'm not getting into it). If one has a large reservoir then it will take longer to fill with bubbles. Thus, the vertical pipe with a hose bib on top. One could use a hose to siphon any air out every few months; just don't let it suck too fast or it will suck air in from the outflow air break. Or one could suck on the hose to suck air out....pretty easy to tell when you start getting water. One could also get a really good idea of failure time for your particular setup through trial and error...water will rise gradually rather than suddenly as air builds up.

For more peace of mind one could instead have a valve at top and bottom of the bubble reservoir. When one wishes to remove air from the loop, one would close bottom, open top, fill tube (pour water into top of tube), close top, open bottom to let water and air change places. Repeat until tube is still full of water when you open top valve.
To see exactly how fast air bubbles build up one could wait a week, then measure how much water is required to top up the tube. This will tell you exactly how much air will typically get in while you are away and let you know if you are in any danger or not while on a trip.

Hydrophilia, thanks much. That helps a lot and we'll work on adding some room for air when we get the new pump. We'll have to take some things apart then so hopefully good for a few days w/ no HSM.