Ultrs violet lights do help a bit.... Duck weed.....gotta keep taking it out mate....yes..a big problem... Swallows should be back in our stable yard soon...we hope so...got a £50quid bet with the wifey...who spots first....lol Frogmannn still about...? Could you not upset the locals.......and keep ya shorts on quietly......or the locals.....will become very aggressive with u fella......imo