I have a system that I am currently building (pictures attached). A total of 440 gallons of water. A pump that is moving water at approximately 86 gallons per hour at about 7' of head.
Two grow beds. For the top bed, I am using a classic autosiphon. On the bottom bed, I am using a loop siphon. The loop siphon is having issues; for example, even when the bottom bed is almost completely full, I am not seeing any water in the tube.
All fittings for the loop are 1-1/2", while the pump delivers water through tubes that are 3/4".
Anyways, it would be great to get some suggestions from folks; I have a few ideas as to why the siphon might not work in practice just based on comparing a few things to a few pictures, but I dont want to make any major changes until I get a bit of insight from folks.
>.. What was your source for the idea?
Partly necessity partly youtube. Here are a few sources;
Good morning Joe,
>.. I looked at the last entry on YouTube. He added a note that he no longer uses the loop siphon on May 2014. In the comments space he does NOT say why. I suspect that it was more problematic than he expected. Could you sketch out your drain system on paper, copy over with dark marker, and show a picture? (or similar)
>.. One immediate suggestion is to fill the the drain pipe full of water, no or almost no air in the tube, cork the fishtank end and fill with water, reconnect the pipe at the drain out fitting and remove the cork under water. The video showed an air bubble and as my son pointed out, that may prove to be a complete or partial blockage.
>.. To me it looks like a design to keep a constant drain on the water as opposed to flood and drain, as the base is at the bottom and it seems to be a constant pulsating, which would keep the level of the water at a low level. This may be problematic on more than two causes: easily clogged by roots and very small pebbles (or dust wash), and insufficient drainage causing over flow.
>.. I am curious as to why you chose this method of drainage? Are you thinking of bi-level or dual level growing media? Earth over media? Otherwise, I can think of no good reason for constant drainage, with such a design.
I mostly chose the method out of a hasty necessity; the bottom most bed exists in order to increase growing area, and the entire greenhouse and system were built around an existing pond we are reusing.
Thanks for the heads up on the YouTube comment, and on the suggestion of priming the tube.
No I am not using a dual growing method, it just made the most sense to cut the hole as close to the bottom as possible and to use a loop as I cant get under the bed. As far as the use of a siphon, part of me just really likes the challenge of getting em to work and the other part of me likes how cool they are when they do.
In the second to last paragraph, you mention the use of a constant drain, which is a conclusion Ive come to myself as a possible solution, but in the last paragraph you mention not using constant drainage. Just wanna make sure Im reading you loud and clear before I start making some decisions and making new holes or buying more tubes.
Also, Im a bit gun shy of putting another hole in this thing; for one, right now even with the bed almost completely full, the water from the pond isnt even making a cameo in the tube, and for two I am seeing some significant leaks from the bulkhead fittings. Those can be fixed but I've thrown some JB WaterWeld at it and it still hasnt stopped! I am thinking my next step is going to have to be pretty intensive and Im still figuring out what thats going to take; heading out there with a wrench later today..
Any suggestions on a standpipe? I was thinking of drilling another hole in the top on the side and throwing in a bulkhead fitting with some PVC guiding the water back to the pond.
Thanks for helping with piecing together a solution! Here's a few more pictures; not the best drawer! Let me know if I can get something clearer for ya. Thanks again!
>.. Constant drain, like standpipe allows for a constant amount of water to maintain a consistent height in your bed. I do not use these, as I do flood and drain. BUT for some purposes, a standpipe is pretty valuable.
>.. I am not seeing the over all design of the loop. But I did notice two issues that you might want to revisit. 1: the pipe is not smooth on the interior, or at least it appears to ridged, if this is true, then water has to overcome each ridge to move through the pipe. This may slow the flow and cause other issues as well.Clear or black flexible PVC tubing is easily obtained at the big box stores and some of the local hardware stores, it lasts. 2: the pipe has rises in he curve of the pipe. Rises can be blocked with air, seriously impeding water flow. Turn the rises 90 degrees to either side to allow level or slightly descending flow of water, dips can cause similar problems.
>.. Leaks are best fitted with gaskets better than glue, as that is what the gasket is designed to do. If the leak is actually coming from a join of the pipe with the bulkhead fitting, twist it tighter. LAST resort is to use 100% silicone in a tube to caulk around the joint, But this only hides the mistake, does not fix it. GLUE is not a good choice until the design is perfected, as any disassembly is made MUCH more difficult and ultimately destructive. (It took my son two undo-actions to figure it out, and now we have no glue throughout the system.) Silicone does not dry stiff, and can be scraped off when necessary. Glue on the other hand is difficult to manage.
Good thoughts for sure. In general here is how the design is; bulkhead fitting from inside to outside, PVC 90 on outside to the yellow threaded thing, and the tube is slipped onto that. I have gotten a few other suggestions from folks, for example the outlet of the tube is higher than the inlet which is cause for problems, the 90 could be restricting flow, and that the loop outlet needs to be vertical. You have any suggestions on removing the JB Weld? I agree with you on the glue; its just worked so well as a solid long term fix in the past that I was shocked to find it fail me now!
Thanks again Lloyd.
Ignore the jbweld. Just silicone over it. 100% silicone in a tube, small tube is plenty: $2-5.00.
Sounds good. Was able to remove the JB Weld yesterday; dremel and flat head screw driver....no holes in the pond liner! Was able to fix one of the leaks yesterday and will be finding time to fix the second one today. Picked up a few new pieces for the loop siphon and have been trying to figure out how to work a few PVC parts out of the design to keep parts of the loop low enough and high enough to get it working.
Thanks for the guidance Lloyd.