There are various aquaponics setup, in this post I write about Timed Flood and Drain System.
A strainer tube (not shown), should be place around the stand pipe to prevent gravel entering the tube.
Above diagram shows, typical components on a Timed Flood and Drain Setup (minus the timer). The ball valve is an option, it is use to restrict water flow in, in situation where you use 1 pump for multiple growth bed or in situation where the pump is too strong.
Diagram above shows during pump operation, water will flow in and once reach top of stand pipe it just over flow. Stand pipe is use to set the high water level.
Diagram above shows during pump OFF, water will slowly drain via the small leak hole at the base of the stand pipe (sometimes somewhere else). The idea is to ensure water not left standing and as its drain it will draw oxygen to the roots and microbes.
This system is widely use due to its simplicity and easy to setup. In this setup components that we need to worry about is the timer. Timers are relatively cheap so that will not be much of an issue.
As long as the timer don't fail while you are on long vacation then its ok.