Hi ive read lots of posts on the forum,i use clay pots,as the uv in hong kong sooner of later gets to the plastic ones.Which i put in the bottom stones,which help the soil to settle with out falling out the large hole you find in that type of pot.And i believe helps drain the compost quicker,in the summer months its the wet season,about two and half months. I just use standard peat based compost,which is quite costly here. Any ideas on improvment or home made compost,there are some sawmills in hk for bark!

You must be using the term "potting compost" to refer to pot mix/ pot media, as they do in the UK. Othertwise compost is used to describe the aerobic breakdown of plant waste materials. In Australia most pot mix is made of composted pine bark. It is hammer milled and or shredded to get the size down, then composted using Urea or Ammonoum Nitrate etc as the N source.The minimum heap is 1 cubic metre to get the heat build up to kill pathogens. You would need more info than this, but you could compost your own.Other barks from other tree species may be toxic/inhihbiting to plant growth. You should check what wood the saw mill processes.
For alternatives, their are many versions of pot mix, depending on what is locally cheap and available. Sand/peat or sand/coir such as the UC mixes could be used if you can get a suitable sand.
Some people find insect screen mesh, to cover the pots drain hole a better method than the layer of stone.

Some people still use compost (broken down organic materials) as a potting medium, and it was all that people used in containers before bags of potting soil was available at the stores.

I personally have used 1 part compost and 1 part crushed pine bark pieces as a potting mix, and others use even higher pine bark ratio (which I am going to try on my next batch). I have many pine trees on my small lot and have plenty of bark just falling from the sky. The pine bark, as you mentioned, increases the drainage in the container and reduces or resists compaction.

The other barks Pagnr is referring to are barks from hardwoods that contain high levels of Manganese. Bark from any conifer tree will work fine. A good potting media for citrus needs to be fast draining with lots of air pockets and capable of retaining enough moisture to last for several days to a week. Peat moss added to pine bark at a 1:4 ratio works well.

Apart from excess Manganese from hardwoods, some tropical timber species have actual toxins. Not sure if bark from green logs would get to Artie10's sawmills in Hong Kong, but sawdust from some tree spp might. Best to check what the sawmill is processing.
Pine bark from sawmills is going to be the whole live 'green' stripped bark. Usually it has to be aged or moist aged to cure it. This aged product can be used in pot mix, but it uses much Nitrogen from the added fertilizer. I found that pot mix made from only aged pine bark had a lot of problems with wood rotting fungi taking over the pots. Composted pine barks are cured better, and I didn't get the fungal growth and mushroom problems. Also the Nitrogen use by the mix is much lower.
John Bonzo and some other members have mentioned free pine bark from their area. Perhaps they are getting the dead outer loose bark, which is probably pretty well cured by sun and rain, and wouldn't have the problems of sawmill products ?

HI all,thanks for your advice,i will check out the bark,at the local sawmills and woods,and get a composter for vegtable waste.artie