I just finished setting up my first aquaponics system! :)))))) It has a 75g fish tank, and 55g of growbed space. I plan on adding more once I get everything cycled and a crop in the clay. Speaking of, I just put in some used hydroton that had been "recently rinsed" (apparently not), and my tank is BROWN! So i start pumping water out of the tank and rinsing the clay balls and swishing them around and cycling the water out. Still dirty. Anyways I can keep cycling water, take out the hydroton and give them a thorough clean, or I just read about the option of leaving it, and letting it settle on the bottom of the tank, and then siphoning it out. I figured I'd ask you guys what you thought. So what do you recommend? :D
In my small system I just let it run until the tank water was clear. The clay just settled to the bottom. I just left it there while I fishless cycled the tank when the cycle was finished. The clay that was settled just ended up back into the grow bed. Didn’t worry too much about it, of course I didn’t have an overabundance of settling.
There is always some fine sediment with moved media. I expect it just needs to settle.
(Now if you are putting in new gravel, I do say rinse because some stuff can be really dirty and full of sand or clay which you really don't want settling to the bottom of your grow bed or fish tank but the worst that will happen with unwashed expanded clay might be a temporarily elevated pH from the oxides left by the kilns.