My pool people told me that my Solar Sun Rings were increasing the algae growth in my pool. They cover about 60% of the pool. They told me that since I have an older pool with some scrapes in the plaster that algae is attracted to, the solar sun rings were blocking the sun and causing the algae (they say "black algae") growth. This didn't sound right to me because we have them turned to let light into the pool and increasing the temperature. What does everyone think?