How to Clean Lime Scale From a Fish Tank

Cleaning lime scale from your fish tank each month is important to keep your heater, pumps, tubing and lights working and to prevent unsightly white buildup on aquarium glass. Lime scale is made of calcium carbonate, a white mineral that forms deposits on aquarium glass and equipment. Acids and commercial cleaners dissolve lime scale, but can harm you and your aquatic plants and animals. White vinegar and lemon juice are safe alternatives.

Things You'll Need

  • White vinegar
  • Water
  • Salt (optional)
  • Razor blade (optional)
  • Rag
  • Lemon juice (optional)
  • Formic, citric or hydrochloric acid (optional)
  • Commercial lime scale dissolver (optional)
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Instructions

  1. How to Remove Lime Scale from a Fish Tank

    • 1

      Remove fish and drain fish tank.

    • 2

      Wash the fish tank and lime-encrusted equipment with warm, fresh water and a rag to remove dirt and salt crystals.

    • 3

      Soak lime deposits on your fish tank and equipment with white vinegar (acetic acid). Use a saturated rag, or immerse deposits in vinegar. Depending on their severity, deposits might dissolve on contact or could take up to 4 hours to break down.

    • 4

      Remove the rag or check the vinegar solution you're using to soak lime scale away. Dissolving lime scale forms carbon dioxide bubbles. When bubbles stop rising, or the appearance of the scale beneath the rag stops changing, replenish your acid.

    • 5

      Repeat Steps 3 and 4 until bubbles stop rising, scale appearance stops changing or no lime scale remains.

    • 6

      Scrub stubborn lime scale off with a Teflon-safe scouring pad that will not scratch aquarium glass, or use a razor blade to scrape it away.

    • 7

      Apply a paste made from salt moistened with vinegar directly to any remaining lime scale. Allow to sit for an hour.

    • 8

      Rinse fish tank and equipment with warm, clean water.

    • 9

      If needed, follow manufacturer instructions to apply a slightly stronger acid, such as formic acid (found in coffee machine cleaners), citric acid or diluted hydrochloric acid or a commercial aquarium cleaner, such as Python's Rydyt or Foster and Smith's Ezeclean to remove any remaining scale. Wear gloves and eye protection during this step.

    • 10

      Dilute acidic cleaning solution with at least a gallon of running water as you drain it down your sink. Rinse the fish tank and equipment thoroughly with clean, warm water.

    • 11

      Reconnect equipment and refill tank with water and fish.