The perfect solution to sealing concrete ponds
Concrete based ponds need the final render sealing to stop the water getting in and lime leaking out. G4 has been long established as the market leader for this task. You need 3 coats of clear G4 when you apply it to a pond. This is a total of 550g per square metre. There is enough in a 25kg tin to cover 45sqm (equivalent to a pond 5m long x 5m wide x 1m deep)
Green water is a problem that many pond keepers have to deal with, especially in the summer months.