If you are retaining water from creatine, your dosage is too high and you aren't drinking enough water. There is no reason to supplement with more then 5g of creatine per day. Once your creatine phosphate levels are saturated, any additional creatine is just going to cause side effects like GI distress and water retention.
The best natural diuretic is dandelion root. You can buy it as a tea and kill two birds with one stone. You get the benefits of dandelion root and increase your water intake that way. It doesn't taste bad. I like to mix one green tea bag with one dandelion root tea bag. It gives the green tea a sort of herbal taste.
Seems like you are taking way too much creatine if it is causing you such a noticeable water retention. Your best bet would be to drink more water, and in addition to dandelion root tea, you may as well drink more green tea or coffee - both of them have diuretic properties.
don't use diurectics ever. your body depends on water to survive.
a lot of times we bloat because we are sensitive to what we are putting in our body and we aren't drinking enough water.
you should read the ingredients of that creatine, i bet it has a lot of stuff in it that you didn't know.. thats why i only use ancient strength, its pure ingredients