Safely Using Bleach to Clean Your Aquarium

When discussing using bleach to clean an aquarium, safety concerns often arise. Is bleach safe? Yes, it is—when used in proper concentrations, bleach is safe for aquarium use.

For those who gasp in disbelief at that statement, here's another fact you should know: bleach is the CDC's (Centers for Disease Control) approved method for sanitizing drinking water following disasters. Yes, many thousands of people have partaken of bleach-treated water, and it caused no health disasters. Bleach is a perfectly acceptable chemical to use for disinfection purposes, provided it is used correctly and in the proper proportions. Bleach (after all) contains a concentrated form of the same chlorine that is used to disinfect most urban drinking water.

Having said that, when used in the wrong concentration or if combined with other chemicals, bleach can be hazardous. So which is it—is using bleach safe or not? If you follow the rules, bleach is safe to clean your aquarium, equipment, and even plants. It will safely and effectively disinfect glass, equipment, and accessories in your fish tank.

Bleach Safety

Following a few critical rules ensures safe bleach use without harming yourself or your fish.

• Don't mix bleach with any other chemicals. That includes soap, aquarium chemicals, or other cleaning products. Use only bleach and plain water.
• Don't use bleach in concentrations higher than ten percent.
• Don't soak anything in bleach for longer than fifteen minutes.

How to Bleach

Prepare a 10% bleach solution by mixing nine parts water with one part bleach in a clean container (e.g., 9 cups water to 1 cup bleach). Soak aquarium items in this solution for ten to fifteen minutes. For an entire aquarium, fill it with the bleach solution.

After soaking, drain the bleach solution, rinse the container, and refill it with clear water. Soak the items again in fresh water for fifteen minutes, rinse thoroughly, and air dry completely. Proper rinsing neutralizes and removes any bleach residue.

What to Bleach

You can safely clean most non-porous items in your aquarium with bleach. That includes:

• Aquarium (either glass or Plexiglas)
• Non-porous aquarium equipment and parts, such as the filter hoses
• Plastic plants (bleach is fantastic for killing off algae on artificial plants)
• Gravel and rocks

Avoid using bleach on silk plants, brightly colored gravel, or decorations, as bleaching will fade them. Avoid wood and other porous items that can absorb and retain bleach.

Mineral Deposits (Lime)

For white crusty mineral deposits, skip the bleach. Use vinegar instead, as it's highly effective. While commercial products are available, simple household items like vinegar often work just as well.