Yep - I would check the MSDS on it and see what the actual content is of the oxalic. We've used the Flood product in a pinch. There is a real distinct possibility that you could order from a company that specializes in products for decks that will have a higher content of the oxalic acid, thus allowing you to use less product, produce better results and making you extra money (which is what it's about, right?) We prefer Steve Rowlett's DeckBrite, however, Pressure Tek has a good oxalic product as does ESI (through Sunbrite supply).
Now if you're environmentally conscious, citric acid will give the same results only in a longer period of time.....oxalic = about 2 minutes results, citric = about 5-7 minutes results.
Oxalic acid can cause sterilization if proper PPE is not used - if you still want kids, maybe citric acid is the way to go.
Feel free to give me a call,
Celeste