Check the listing for details. Sea-Lab #28 Automatic Replenisher 1 Kilo Block Calcium Strontium Trace Elements. Condition: New. Listed at 35.99 USD. Sea-Lab #28 Automatic Replenisher 1 Kilo Block Sea-Lab #28 restores and maintains the concentration of calcium, strontium and all trace elements at the same levels found in the sea, automatically. Formula #28 always works, and cannot be overdosed. This is not a slow-dissolve or time-release product. It dissolves only to replace depleted elements. Automatically controls concentrations of 28 elements including calcium, strontium and all 15 essential trace elements. Removes heavy metals and limits ammonia and phosphate while helping to buffer aquarium pH. Benefits: 1. Removes heavy metals and limits ammonia and phosphate 2. Supplies all essential trace elements 3. Maintains a consistent supply of calcium and strontium 4. Stabilizes acid-alkaline balance (pH) 5. Prevents toxic ammonia build-up Size: 1 Kilogram Block