Thank you for posting a great question and welcome to the community! I am a flooring associate at the Home Depot that has answered many a granite countertop question almost every week really. Ironically, the best products we sell for your solution is not in the flooring department where our granite cleaners are located but in the kitchens department at our store where we sell a great line of products to get those water stains out. The company that makes these is Stone Care International, or SCI. The line of cleaners that they use is specifically made for stone countertops. With that said, its the only product I can guarantee that is safe to use around food grade surface areas, where health as well as solution is needed. It requires no rinsing and is simple to use. The top picture is the one we'll called Plan A, its an item available in the stores that should remedy your hard water stain removal.
The picture above this sentence is what we'll call "Plan B". It is a poultice, or extractor that is used with covering up the stain area with this applied by a plastic sheet, that soaks up the stain as well as drives any existing stains that are deep in the granite down any further. This leaves a spotless area ready to be resealed. Judging that they are hard water stains, after you clean the hard water stains, test the countertops with a few drops of water. If it soaks into the granite within a minute, you'll need to reseal your granite countertops. Just like any maintenance on an investment, natural stone countertops require sealant at minumum of every few years. The sealers are also available in the same section, same company as you got your countertop "Plan A" cleaner. Spray or wipe on the sealant, and let it set a few hours before usage. That away, you'll never have to worry about having hard water stains really ever again! Prevention is the key after getting these stains out, so sealant is really the answer to never having to do this again, other than routine sealing.
Thanks and welcome to the community again Rmeegan!
Yes, please update us on how the removal of the stains went, we always like to hear feedback and giving the right solutions for our community members!
I am looking for a product that would take off the hard water stains from my granite floor in the shower. Can you help me? Thank you!!
For hard water stains, try applying poultice to the stain. A poultice made of corn starch or baking soda mixed with water to form a paste may do the trick. Cover the poultice with plastic wrap, and leave it on for 24 hours. Rinse and dry the area. For regular cleaning, you can use a granite cleaner that is approved for granite countertops or a mixture of one part white vinegar and two parts water will not damage the granite and is environmentally friendly, and economical. If your Granite counter gets stained easily by water, it is a sign that the sealer is getting weak. Seal it once every year to bring back its original shinny look. You should look for a trained professional to seal your counter. Check this product as well http://www.myinstalledcountertops.com/seal-your-granite.html