How to Clean Hard Water Stains from Aquarium Glass

One of the maintenance issues a tropical fish hobbyist becomes familiar with is removing hard water stains from the walls of the aquarium. These whitish lime and mineral deposits build up in time--more quickly if the local tap is hard water. If attended to immediately, they can easily by scraped off using a razor blade. But if left to grow thick, the stains become quite a challenge to remove. Fortunately, simple household remedies can do the trick.

Things You'll Need

  • Razor blade
  • White vinegar
  • Soft sponge or microfiber towel
  • Dishtowel or hand towel
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Instructions

    • 1

      Empty the aquarium. If the aquarium houses a fish community, transfer them to another tank. Remove all the décor and gravel, which can get contaminated during the cleaning process.

    • 2

      Scrape the thick lime deposits with a razor blade. Thick lime deposits will come off easily with a sharp blade. Take care not to scratch the glass with the corner ends of the blade. Apply some vinegar to the area to help soften the crusted deposits.

    • 3

      Lay the aquarium on its side and apply vinegar to the stained areas of the aquarium wall sitting at the bottom.

    • 4

      Scrub off as much of the lime scale as you can using a soft sponge or a microfiber towel.

    • 5

      Lay the vinegar-soaked microfiber towel on the glass to dissolve the remaining stains. Add a vinegar-soaked dishtowel to cover the rest of the affected aquarium glass. Let the vinegar soak for several hours (the towels will keep the vinegar from drying out too quickly).

    • 6

      Repeat the process on the other three walls of the aquarium. Let the vinegar soak for several hours per side to achieve the best results.

    • 7

      Rinse the aquarium thoroughly to remove all traces of the vinegar and lime deposits.

    • 8

      Consider scouring the sides of the aquarium with rock salt to dislodge and dissolve the hard water deposits.

    • 9

      Consider using a paste of vinegar and baking soda. Rinse the tank thoroughly afterwards.