It will be tomorrow PM before I can really reply.

Meanwhile,

+ Remove the tabs and the Nature2. You can throw the Nature2 away now, or later - but it's worthless. Keep the tabs, but leave them OUTSIDE in an uncovered plastic bucket.
+ Run your filter 24/7
+ Buy some polyquat and begin dosing with it ( http://www.poolsolutions.com/gd/polyquat.html )
+ Add SMALL doses of bleach -- 1 quart at a time in the evening via the skimmer. BUT, *ONLY* after you remove the tabs and Nature2
+ Try to find a LIQUID stain and scale remover and dose with that, as well. Do NOT over dose -- follow the label.
+ Get a cheap OTO / phenol red drops kit, and use it to keep your chlorine in the 0.5 - 1.0 range, and your pH 7.0 - 7.2
+ Be SURE to keep filtering.
+ If you need to add more water, do so via the skimmer.

Good luck; explanations tomorrow (or Monday)

Ben