Advanced aquaponics
Sand as a medium in a flood and drain bed?
I have taken an interest in using sand as a media in one of my grow beds again. Only thing is that my beds cycle permanently on flood and drain auto siphons. I am worried that the sand will pose a considerable problem in continuing this type of water circulation. One option is to put the beds on timed cycle and just use an overflow standpipe with drilled base (overflow if filling rapidly, draining when water is cut). I'm not too keen on this, as I am intent on keeping the "no aerator" idea going with the use of cascades in the unit.
The next option is to have a small amount of gravel in the bottom of the bed and a screen between the gravel and the sand. This will likely develop management issues in the medium and long term. A final option is just to have a fine mesh strainer on the guard pipe, but I am not sure if this will allow enough water through to efficiently operate the siphon.
Any thoughts on / experience with this issue?
Japan Aquaponics - アクアポニックス 日本
I am late into this discussion, but I wondered if anyone had any updates about their sand systems? I have never used it but thought that this discussion was very interesting. If anyone has any more progress reports I for one would love to hear them!
Jan 10, 2012
Robert Rowe
Kobus
I believe you would save yourself a lot of grief avoiding sand. It's to fine and would slow the drainage. If you used a siphon external to the bed it would help.
Robert
Nov 10, 2012
TCLynx
Robert,
There is a reason this discussion is in Advanced Aquaponics and his testing was done as an experiment. Sounded like it actually worked too but he did take extra steps to deal with the nature o the sand.
This is an old discussion though and I'm only jumping in here because Kobus has had other priorities keeping him busy lately and he may not see this.
(However, would always love to hear what's going on with Kobus when he has the time.)
It is highly unlikely that simply replacing gravel or other course media with sand would ever work. I can see some limited situations where the use of sand could work.
For instance, I have potted plants that are essentially potted in Sand and I've set those plant pots down into some of my gravel beds and that seems to be working quite well.
I am also thinking about trying a version of a recirculating wicking bed that would use sand as the top wicking layers over the water reservoir. (I'm cautious about recirculating aquaponic water through a wicking bed filled with compost since that has the potential of overloading the bio-filtration of a system if it is not very robust.)
Nov 10, 2012