First of all check out this video....
The following information may be helpful to the new Aquapon, who wants to be frugal yet have a system that is functional and thrives.
I have included a few photos to show you the finished product. What I like about this design is that ALL of the parts are readily available, cleans up easily, and is above all it's FREE ! The water pitcher in the gravel cost a dollar at the Dollar Tree store. This holds the grow rocks in place and has holes punched in it for good water flow.
I started out reading the popular PDF file that uses PVC elements for a bell siphon which is a little costly, before finding the above video. I found this method to be very inventive so I had to try it. I use a V8 Fusion bottle for the outside and the top of one of my wife's empty Seltzer bottles on a 1" PVC stand for the inside. The trick is in HOW you cut the bottom out of the outside V8 Fusion bottle. Mine has evolved over time with better and better design cuts.
Here is the best design I have used, so far to cut the bottom of my V8 fusion bottle.
It keeps it's rigid form and yet allows plenty of water to flow through it.
I had experimented with different plastic bottles before deciding on these and here is why.
Some plastic bottles are made with too thin a plastic and the vacuum created with the bell siphon tends to crush them (Pepsi 2 liter bottle). Some bottles are too brittle and spider cracks begin to appear near the neck and top of the bottle. (Generic 2 liter bottles). The V8 Fusion bottle is just right as "Goldie Locks" would say. It holds its shape and does not buckle under the vacuum pressure.
Did I mention they are FREE? (after consuming the beverage of course)
I was amazed at how well this works, and once every few of weeks, as needed, I use a toilet brush from the Dollar Tree Store to brush the algae that collects on outside and inside of the plastic then I also do the same thing with the seltzer funnel and pipe stem. I wash these pieces in the fish tank because the tilapia love to eat the algae. The outside bottle, inside funnel and stem are now clean and ready for re-use.
My Fill & Drain cycle is approximately 2 1/2 minutes to fill, and 2 1/2 minutes drain. I know many folks like a longer fill & drain cycle but as you can see ... my plants are loving it.
Also, I have a diversion valve I can close down if I wanted the fill process to take longer. I have found many ways to be frugal and achieve the same results. It's a lot of fun and educational, I am always discovering better ways of doing things.