Firstly a little about Marblesheen.
There are many types of pool finishes but Marblesheen is an old school system that has been around for decades.
This type of finish was constructed with a concrete shell and composed of white cement and white marble chips and if applied in the 1970’s they also included asbestos, (Yes asbestos!).
Its applied using a trowel with thicknesses ranging from 5 to 25mm and in some cases thicker, however it all depended on the skill of the person doing the job.
If done well it could last 30 years or more but if in a more open porous surface then it may show its age from 10 years old.
Marblesheen will start showing its age as it becomes porous and its white cement is worn away, little crevices appear which algae love to grow within.
Marblesheen will lose its white and slowly become more cream with dark stains and black areas of algae including some rust penetrated areas, at this stage I would advise you have the pool emptied and checked by a professional licensed pool builder.
As the Marblesheen pool ages it will also require more chemicals to obtain a perfect PH balance.
Other stain that affect a Marblesheen is leaves from Eucalyptus trees, the oils stain the Marblesheen, however some chemicals may help in removing them.
Acid washing a Marblesheen is possible, however the acid may damage the finish surface so once again I would seek professional help.
If your Marblesheen is at a point that acid wash can’t help, there is always an option of painting and repairing your pool, www.diypoolpaint.com.au this approach will give you approximately seven years before you have to do it again.
I recently did do an acid wash to a Marblesheen pool and the outcome was reasonable, however there was some stains including rust marks that will need to be approached at another time in the near future.
This was done by emptying the pool overnight, Next day gerni all surfaces and very carefully mix a very light ratio of acid and water, pour over small sections at a time until an even area is achieved.
Once again too much acid may damage the Marblesheen to a point of no return so I would recommend getting someone who know how to!
If this is all too hard, you could always call us at Clean Pools R Us and we would be happy to give you a quote
See attached photos showing start to finish,
Day one; Empty the pool
Day Three; Ready for swimming.