Our fiberglass pool is now 7 years old. The sides under water are starting to feel rough, not smooth & silky like when it was new. Is there anything I can use (other than draining and coating it)to bring the glossy feel back or to at least prevent it from getting worse. I did have some stains this year for the first time when we opened it but I got them out with ascorbic acid. Also what should our pool guy be using when closing each season. We are his only fiberglass pool so I want to make sure he is using the right chemicals. Any help would be appreciated.