i have and have had since last year anyway, some very light gray stains in a # of areas on my vinyl..especially it seems in the deep end.so light it looks like dirt that just won't quite remove. they are not slimy at all..just look like sediment that won't pickup and don't seem to be getting bigger, but i thought i would try to remove them. i've read through some of the stuff here and was thinking about trying vitamin c powder, but read i should use sequesterant first? i have some scale and stain remover, but no vit c powder yet. should i give it a try and if so, how to apply (it's liquid)

thanks