2 ½ Gallon Liquid Chlorine Refill Liquid chlorine is the fastest, least expensive and most effective type of unstabilized chlorine. ServCo offers the freshest and strongest liquid chlorine on the market. Liquid chlorine is available in refillable 2.5 gallon containers and is perfect for shocking and helpful with algae control. Go ServCo when it’s time to shock your pool. ServCo fills its chlorine jugs daily, which means our liquid chlorine is always the freshest.