Is there a way to remove string algae from my pond and rubber liner, without destroying the liner?
String algae is very easy to eliminate, once you know what causes it.  String algae is mostly caused by poor filtration and not enough
beneficial bacteria in the pond.  Too much food is the usual cause of string algae, therefore, stop feeding you fish is the first way to prevent string algae.
Removing fish food from the pond means the fish will begin eating string algae, which will quickly remove the problem.  After the string algae subsides,
feed your fish only what they can eat in five minutes.
Next, you need to make sure that your biological system can handle the amount of waste your fish produce.  YOU CAN NEVER OVER FILTER!  Always use a filter that
is sized higher than the manufacturer recommends.  A common problem with many filter set ups is that too much water flows through the bio filter too quickly, thus
minimizing the cleaning capacity of the filter.  Beneficial bacteria’s are all natural and break down sludge and smells.
Professional Koi breeders  do at least a 20% water change every week.
Don’t be afraid to learn to use a water test kit.  You water goal is to keep the ammonia, nitrite and nitrate at their lowest levels.