Check the listing for details. UltraClear Buffer Block pH Stabilizer (110 Grams) by ABI Inc.. Condition: New. Listed at 27.99 USD. The UltraClear® Buffer Block pH Stabilizer adds essential calcium needed for healthy fish bone growth. It also enhances the growth and survival of beneficial bacteria for a healthy, beautiful pond. Great for snails! The Buffer Block will stabilize the pH and increase water hardness and alkalinity in your pond. Low or no buffering capacity (low alkalinity & calcium carbonates) causes the pH of the pond to become unstable resulting in wide swings of the pH.Application Instructions The Buffer Block treats ponds up to 2000 gallons. Place the Buffer Block in the main water flow of the skimmer, filter or waterfall. Lasts up to 3 weeks. Replace when dissolved.Warning In case of eye contact, immediately flush with plenty of water for at least 15 minutes. Get medical attention. In case of skin contact, wash thoroughly with soap and water. In case of ingestion, do not induce vomiting. Get medical attention immediately.