Just designing my first indoor system and decided to render it to get the wife's approval. Going for a flood and drain loop siphon. My fish will experience a 1/3 tank "tide" which may force me to add some filled up water bottles in the grow bed. Any design hiccups that anyone can see?
Thanks! - Jonathan
A 1/3rd water level fluctuation is fine as long as you are not stocking too heavily.
I will recommend that you put in a small gravel guard around where your drain is in the grow bed so you can inspect the water level as well as clear out any clogs from the drain (roots do eventually grow to the drains) when needed. And your overflow should probably be either lower or bigger or both. If you put it in too low, you can always add a bit of pipe and an elbow to adjust it up where you need.
If your pipe from the pump is 1/2" then you should probably go for a 3/4" loop siphon and the overflow should probably be 1" just to be safe.
Remember to plumb in a bypass with a ball valve to divert excess flow back into the fish tank for aeration and to help in balancing the flow to get the siphon working properly.
It is safer for the fish if you have a major plumbing malfunction that causes the pump to send the water out of the system somehow (like if the feed to the grow bed gets knocked out because you didn't glue it or secure it in some way.) Anyway, having the pump up off the bottom a bit will leave some water for the fish though it could burn up your pump. And if you don't catch the problem soon enough, the fish could still perish as they run out of dissolved oxygen and the water builds up ammonia since it is no longer getting pumped around the system but it would give you a few extra hours to discover the HSM (Heart stopping moment or other words you fill in) before the fish are complete gonners.
So would that be a safety factor of a few hours depending on number size and kind of fish as well as season.
This looks like a nice little system, and really similar to one that I built not long ago. If you would like, please take a look at Japan Aquaponics and the Micro Aquaponics unit - it really is very similar so it may give you some ideas.
Some of the ideas that I incorporated were suggested by TCLynx who has replied here for you, and so you can see some of her modifications in action. The use of the bypass (T-bar in my case) coming off the pump and with a ball-valve added, was really really helpful so I strongly suggest using that otherwise you may have real trouble wit the siphon.
My loop siphon is working nicely now, but in the end I did move the outflow hole from the side of the tank to the bottom - this worked a lot better, perhaps due to added water pressure, but I did have a few problems when I had the outflow hole and siphon on the side of the tank. You might also want to cover the loop for the siphon as it can be easy to get algae growing in there.
The whole system may weigh more than you think and so the legs that you have on the growbed may not balance the system if they are not securely weighted down? I was surprised at how heavy the final system was - even though mine is on wheels it is still a little cumbersome.
Well, by all means take a look at the one that built that looks a little similar to your design (or at least the concept) and if I can answer any practical questions about how I set it up, and teething problems that I had (am having) then I would be very happy to do my best to answer.
That is great that you saw the video, on my profile I had also posted some issues and some solutions from the first system and what I would change and so forth. I dont know how much you will need to move the system about, but I put the wheels on as an afterthought, but am really glad that I did - they do come in handy.
I also added a timer to my pump and that has been good to regulate the water flow a little more and turn the system off at night (it is in my bedroom and so was a little noisy)
For the siphon I used the reinforced tubing as the thinner plastic tubing kinked and so restricted the easy flow of water and therefore the working of the siphon.
I made a new updated video about this system which I have just uploaded, and so by all means have a look if it is of interest!
All the best,