A little late but at least others will find this.
Firstly I must add that I restore decks for a living where the outdoor elements are notorious for harsh UV rays and wide variations in moisture exposure.
The deck above from the original poster has a failed acrylic based oil - sanding will give you that results as strippers will cost a small fortune and still leave some coating behind so sand away.
I recommend starting with a drum sander and start with a 40 grit which will rip it all up with its first attempt - 1 belt should last around 30 sqm.
Once you have given the deck a once over with the 40 hit the deck again with a 80 grit - 1 belt per 30 Sqm will be fine.
Lastly get me decking cleaner which is really just oxalic acid / wet down your deck that spread the acid and let it sit for 20 mins before hosing off or with the help of a high pressure cleaner no stronger than 1000 psi.
Let rest for 24 hours and then seal with your offered protective coating.
Don't be scared of the belt sanders start with a 80 to have practice for 10 mins then back to business
If you can only find a hand held orbital sander buy yourself me knee pads and get your abrasives from floor sanding supplier and buy discs made from zirconia they are blue in colour and last for ages...
Another tip get a wire brush and clean your pads as you go as this all save you lots of money..... same principles apply startth you rough 40 grit and finish with 80..... trust me go the walk behind belt or drum sander and just do edges with your hand held orbital.