Hi Cameron and welcome to the forum
cameron11 wrote:
Is it possible just to have drilled holes in the bottom of the grow tank (top tank) draining directly into the lower fish tank, instead of a syphon and then just alter the tank filling up and draining (by adjusting water flow, pumping time and the number of holes)?
The reason we use standpipes is it takes the water exit point from the GB at the top of the water level, it means the water entering the GB is pushing the water out so to speak. If you have a hole the same diameter as a standpipe (25mm for example) in the bottom of the GB the water level wouldnt build up as gravity would have it dumping straight back out. So to have the water level build up in this example you would have to pump the water in at a fairly large volume therefore your filtration is vastly reduced. If you drilled small holes instead of one big hole to control the water exiting you could face blockage issues and could see you over flooding a bed.
cameron11 wrote:
Also is it possible just to have a hole in the grow tank at the correct height, with a piece of piping attached draining to the fish tank, act as the overflow?
Using an overflow from you GB to FT would see anaerobic zones in your GB as the water entering the GB would take the easy path across the top of the water level and straight back out, basically flowing over the filtration rather than through it.
Hope this helps
