I am new and pretty overwhelmed

[doug.a]

silly old****,
It ight look as though i know where gizzigoo is but i do not due to not putting in ommas i must watch that and i appologise for that omission imy meaning was i new where he was with the mind overload due to reading so much information the second part is that Dori Evans a charactor in the tv show 96 was always saying why wasn't i told i hope that clears up and again i apologise if i have offended anyone, There was a drawing in i believe it was on the practical aquaponics wesbite it showed a line diagrame which as very helpful it also explained some parts i was investigating. anyway enough from me and over to you have a nice weekend.
doug.a

[Murray]

Doug, The theory is that you can support grow beds up to twice the volume of the fish tank. So if you have a 1000 ltr fish tank you can run up to 2000 ltr of grow bed. That theory came from somewhere......
In practical terms a 1:1 ratio is good.

As to volume of water in a grow bed. My grow beds are a total capacity of 585 ltrs. I have measured the water taken to fill one and it is 180 ltrs....so it is 405 ltrs of gravel and 180 ltrs of water. So there is 585 ltrs of gravel with a whole lot of little spaces in between all the pieces of gravel, it takes 180 ltrs of water to fill all those little spaces.
Those ratios will vary a little depending on what type of gravel (grow bed media) that you choose to use.
Doug, old bath tubs are a good resource to get an aquaponics system up and running. Use one for the fish tank and one or two for the grow beds.
They can end up looking a bit ****py in the suburban back yard, sometimes wife gets upset with the back yard looking like a junk yard ..... until you start delivering Tomatoes and Lettuce to the table every day.

[njh]

I started by just playing with small systems. If it doesn't cost much, it doesn't cost much to replace.

I think you could build a reasonable system with a few plastic organiser tubs and a small pump.