VEVOR Pool Filter Balls for Sand Filter, 1.5 lbs, Filter Balls Replace Pool Filter Sand, Reusable Polyester Fiber Filter Media Balls with Wash Bag, for Swimming Pool Above Ground Pool Aquarium Tank

A typical 12-inch sand filter usually takes about 50 lbs of filter sand. Using the common conversion for filter balls, you would need about 1.8–2.0 lbs of filter balls So the 1.5 lb pack is slightly under what most 12-inch filters need — it may work, but ideally you’d want a little more media for full performance. The 3.1 lb size would definitely cover it with some extra. If this answer does not resolve your issue, please contact us again for assistance.