I opened up to scale this spring, and so I just ordered this product and now my pool store is telling me it is not compatible with biguanide. Is this true? I looked at the label closely and it says the product is for chlorine and bromine pools. So does this mean I can't use it for my pool? The product the pool store is recommending to get rid of scale is SoftSwim's Stain Control. Isn't that more for metal staining and prevention?