Renew is ideal for use in systems where phosphate released from all activated carbons Poses a problem. Renew is also less aggressive than carbon, making it well suited for reefs and planted aquaria. It is also beneficial for use in soft water aquaria where the ph-raising property of many carbons is not an asset. Renew will remove Organics and particulates in the sub-micron range; It will also help control ammonia, nitrates, and phosphates. This product is sold by volume. Cited weight is minimal weight.