When hooking up at any park we always spray the water hydrant and spray a few shots in our hose. We also spray a few shots in the other end of the hose before the filters. Only once did we have any algae and the was one of those screen washers in a "y" connections. About every 3-4 months I put some bleach in all our hoses and slosh it back and forth a few times. Then rum water through it to take out the bleach taste. We are full timers and our hoses are used almost every day. About one a year we replace our hoses.