How to verbs sandstone? I have slightly a bit of sandstone around my patio and pool,...

I have slightly a bit of sandstone around my patio and pool, unfortunatly it be not sealed when it be installed. After 2 years it is quite stained after have potted plants put on it and also the wet weather. I hold pressure washed it several times although this get rid of the majority of it the outlines of the pots still remain. Also some of the stains have a green tinge which might be algae imbedded contained by the stone. As I live in Thailand most commercial preparations are not available here although I can probably carry most basic chemicals.
Do I involve to adaptation "grease drain plug"...
Answers:    I believe you obligation acid to verbs it.Make sure the area you are cleaning,a small bit at the time is damp with river before you put the tart on it.That will save you have drop spots later.Keep it damp with more sea for about 5 minutes and after rinse with large amounts of water.When it is dry save all traffic sour it as it becomes porous and glib to stain again.When you finished this washing,and when it is adjectives bone dry carefully trademark it with an apropriate sealer.In England they own many products for this.Look at the websites of Lithofin and/or HG to find what would be best.
When I drain marine, I can hear hose...
we use to own the same problem near that, we are a landscaping company, the solution,, we use 'boysen emulsion' we bought on a hardware, the soft purpose is to seal the sandstone from hose and dirt, even thought it had a algae contained by it the emulsion works the same