Backyard Aquaponics
A place to discuss aquaponics

I'm working on the plumbing on my small system-

40 gal / 155 L stock tank on floor for FT
24 gal/ 90 L Rubbermaid HDPE storage box on stand for GB
190 gph Pondmaster pump
3/4" cpvc T, threaded fitting, cpvc pipes and 3/4" tube fittings and vinyl tubing
3/4" bulkhead fitting installed as overflow below holes for handles on upper sides of GB

DH installed the bulkhead fitting for an overflow below the handle insert at the side top of the GB. It has 3/4" threaded tubing fitting attached to a downward elbow tubing fitting. I made a venturi drain aka SLO on the polls I think, with unglued cpvc pipe and fittings, and ran a test on it today. At the point that the water started to overflow the top of the T, and get up to the handle holes, I put some vinyl tubing on the outer elbow to the FT, and the venturi effect kicked in, it started siphoning and the level dropped to being sucked in a whirlpool into the T. Really cool. I turned the pump speed (unmarked on the pump) cw and apparently this slowed the pump down so that the water level stayed below the top of the T. I shoved a plastic sandwich bag into the top of the T and stuffed it with packing peanuts. I shut off the pump and it was siphoning out but probably through the pump tubing.

I need to figure out how to also have the GB F & D, if I set up the same hole system on the other side of the GB and made the venturi drain with an elbow instead of a T, I assuming it should siphon? I want to have the holes up high partly because the system will be in my dining room by a west facing sliding glass door for the lighting, and partly because I already have a stand for the GB but would have to build one to raise it above the FT and also then I would limit the height of the plants more and want to grow some pole beans. Does this sound plausible? I could buy a larger bulkhead fitting and larger cpvc tubings and fittings next time for either the siphon side or the overflow side as I can still change everything around. Does having a larger pipe size make the siphoning action harder?

HB

I ran another test today putting an elbow in instead of the T to try to make it siphon but without glue there was air entering at the joints, so the water got way over the pipe and started leaking out the red handle holes, then the air bubbles starting coming out the external tubing and the siphoning started working, but once the water level dropped below the elbow and air was getting in again, the siphoning stopped. I guess I can't do a real test without glueing everything together, but at that point I also can't take it apart easily anymore. I didn't feel from what I could see that the siphoning would keep up enough with the pump to have the pump on continuously and still completely drain? Has anyone used a J siphon with a continuous pump? Do my pipes need to be a bigger diameter than 3/4" / 19mm to siphon faster? I'm trying to avoid having the pump shut off since it's supposed to shorten the life.

HB

HB,

maybe you could try wrapping the joints with plastic electrical tape to eliminate airleaks but still allowing pipes to be disassembled for tweaking

Dicko

Thanks, Dicko, could work. I got some more polyethylene fittings today, another one to screw into the bulkhead on the inside, and another elbow of the type that you put vinyl tubing on, like I have on the outside. I like that it can be disassembled. I tested my glued pvc no holes overflow but it must have had some air left in it because it never siphoned, or it was because the water level in the stock tank is way below that of the GB. I'm considering having DH drill another hole below the present hole and put on a loop siphon. Then I would only have to make a gravel separator/ standpipe on one side of the GB. I'm hoping the loop siphon would be reliable and drain the bed fast. I still would like to operate my pump continuously, I may try someone's idea to split the tubing coming from the pump and put part back into the FT which would slow down the filling of the GB. I guess next I need to try the loop siphon and see. Or I could retest the J siphon with the electrical tape, or put on the PE fittings and vinyl tubing. So much fun but I would like to get some plants growing soon. My outdoor vegetables are fizzling, though the greens should keep going in winter. Had to go out and move a fence because the deer started eating some of my collards. GRRR. I guess you Aussies may just be starting into the growing season?

HB

Silastic on your fitting will allow you to take it apart later. Just get the 100% pure or aquarium safe.

im a hot gleu gun addict, love the quick dry time

Go the loop siphon - very adjustable and reliable.

And yep Growing season is great.

DH drilled a bottom side hole for me under the overflow hole so after the Aquarium silicone adhesive cures in a couple of days, I hope to finish putting in a loop siphon, adjust it, put gravel in the growbed, and start running the water. I hope I don't have too much trouble adjusting the pump flow rate and siphon.

I decided to go ahead and fill some plastic hydro cups with Hydroton and put some seeds in them to get started on growing stuff. I plan to try some pole beans since I can't find them in the store here unlike most of the stuff I could grow.

HB

Mizzie- Do you use the hot glue on pvc fittings? Can it be taken apart afterward, and does it have any toxicity?

DH

Still continuing set up experiments. Today I connected the PE fittings and vinyl tubing to the bulkhead, and ran the pump. It took 6 minutes to fill the GB and when the loop siphon kicked in, it was keeping up about even with the pump. I turned off the pump and it took 6 minutes to siphon out to the bulkhead opening, leaving 1.5" / 38 mm of water in the GB. I don't know how adding gravel will affect the times, I would think since there would be less water the times would be shorter. I'm thinking of splitting the pump output between the GB and a line back to the FT which would also aerate the FT, I don't know if this will slow it down enough to allow the loop siphon to drain the GB. I guess that will be my next experiment. Anyone who had tried this like to comment? I would like to run the pump continuously but it seems I may have to put it on a timer instead.

In the photo is my attempt at an overflow siphon which didn't siphon, maybe the old seals (pvc from a garage sale) didn't really hold water.

HB

You need to slow your inflow rate to break the siphon properly....

Tee'ing off and returning a line back to the FT will acheive this, while also providing aeration as you suggest... way to go IMO.... and commonly employed....

This will also allow you to run the pump continuously....

The other option would be to incorporate a ball valve to slow the flow into the growbed.... and/or a timer... but this may restrict the pump and shorten its life...

Stick a ball valve on both the growbed inflow and the tee to the FT... then you can both isolate and/or adjust the flow to either line...

I've been running the Loop Siphon and I'm having problems on both ends of the F & D. It fills fine, then it won't initiate the siphon and drain unless I lower the end of the tubing from the siphon below the surface of the water. Without lowering it water comes out of the siphon in balance with the water coming in through the pump. The water goes high enough to also cause the SLO to kick in. After lowering the end of the tubing air bubbles come out and then more water so the GB drains. Then when it gets down to the level of the lower bulkhead with the Loop Siphon, it reaches another equilibrium between the siphon continuing to siphon and the pump bringing in water and it sits there. I have to raise the end of the tubing coming from the siphon above the water level, which allows some air to enter and breaks the siphon so the GB starts to fill again. What can I do to tweak this situation so the tube doesn't have to be raised and lowered?

We put the GB up on another stand to above the FT and there didn't seem to be any improvement.

Meanwhile I planted some seeds in Hydroton in Hydroponics baskets....

HB
I used to be indecisive but now I'm not sure.

HB there are perhaps 3 siphon threads around, that discuss the possibilities and best fixes. I suggest you find one and post your question there... Another detailed thread will get confusing when we try to reference it.

here are some links (I haven't read them, just searched, so sorry if some lack the info)
http://www.backyardaquaponics.com/forum/viewtopic.php?f=8&t=484&st=0&sk=t&sd=a&hilit=siphon
http://www.backyardaquaponics.com/forum/viewtopic.php?f=1&t=4316&st=0&sk=t&sd=a&hilit=siphon
http://www.tiwalkme.org/BellAndSiphon.htm
http://www.backyardaquaponics.com/forum/viewtopic.php?f=8&t=4154&start=0&st=0&sk=t&sd=a&hilit=siphon

but quickly...

If the siphon wont start you either need to decrease the siphon tubeing size, or increase the pump flow rate.

To stop a siphon put a breather pipe from the top of the siphon loop, to the point inside the growbed that you want the siphon to stop at. When the water level drops below the breather tube, it sucks in air and breaks the siphon.

Perservere - its worth the effort to have siphons working well.

Thanks for the links, KP. I've read them before but they didn't all register. I took out the elbow coming out of the bulkhead and shortened the hose. The hose end still seemed to want to be underwater to start siphoning hard so I stuck the end in a yogurt cup and put holes in the bottom of the cup. It did make the siphon start better, I'm not sure if the water leaked out well enough to break it off since I had to leave and couldn't work on it anymore, but I got the impression it worked. If not I can try your idea, OBO.

What do most people do with the end of the Loop siphon hose, is it going into a larger pipe and is it submerged? I don't know why it seems to work better if underwater, it seems to need to get rid of all the air.

I'm still needing some way to adjust the relative strength of the pump tube split back to the FT versus the tube going to the GB. The FT one coming from the Toro T is low, and got too strong so I put a vinyl hose on it that didn't quite seal and ran it up to the GB so at least part was going up there. Since I'm using a 3/8" Toro T because I couldn't get the 1/2" corrugated pump pipe onto the 1/2" PE fittings, I really need a 3/8" valve of some kind to put in line. I went to the hardware store and they didn't seem to have anything like that. The valve fittings I've seen were for cpvc, incompatible with the Toro T and the 1/2" tubing. My, but there are a lot of problems in AP, or maybe it's just because I don't want to work with pvc. What kind of line do most people have coming off the pump? Mine has a 1/2" outlet.

HB