1-800-566-3474

Aquarium Pharmaceuticals FilStar Water Softener Pillow

Write a Review


AP7341

This item has been discontinued.

Aquarium Pharmaceuticals, API, MARS Fishcare

Canister filter media designed to fit the FilStar XP. Removes hard water minerals and reduces General Hardness (GH) in freshwater. Rechargeable pouch.

Water Softener Pillow™ - for fresh water:

  • Reduces crusty mineral deposits
  • Reduces GH (general hardness) and maintains soft water
  • Removes toxic heavy metals
  • Completely rechargeable
The Water Softener Pillow removes hard water minerals and toxic heavy metals from aquarium water. It consists of a special "pillow" that fits into the RENA Filstar Canister Filter, providing continuous removal of minerals and heavy metals. Providing an aquarium with softer water improves fish health and can prevent unsightly mineral deposits from forming on the aquarium surfaces. Many fishes, such as tetras, angelfish and South American cichlids prefer the soft water common to the Amazon River Basin, (50 to 100 pm GH, typically). The Water Softener Pillow helps to re-create the soft water found in many tropical areas of the world where aquarium fish come from. Maintaining a stable aquarium environment is much easier when using the Water Softener Pillow.

How the Water Softener Pillow Works: The Water Softener Pillow contains a special ion-exchange resin that selectively removes hard water minerals, such as calcium and magnesium, and heavy metals, such as copper and iron, from freshwater aquariums. In the ion-exchange process, sodium ions in the resins are exchanged for heavy metals, calcium and magnesium that cause hard water. When the ion-exchange process is complete, the pouch is recharged by placing the pillow in a salt solution. Recharging the pillow reverses the ion-exchange process and makes the pouch ready for re-use. Because this process exchanges only sodium, it does not add salt to the aquarium, only harmless sodium ions. NOTE: heavy metals, like copper and iron, permanently bind to the resin beads in the Water Softener Pillow. This can gradually reduce the efficiency of the pillow. If the Water Softener Pillow ceases to function properly after recharging, it must be replaced.

Directions for use in RENA® FilStar Filters:
  • Remove the Water Softener Pillow pouch from plastic bag.
  • DO NOT open the Water Softener Pillow pouch. One 400 g should be used for every 110 U.S. gallons (417 L) of aquarium water.
  • Flatten the Water Softener Pillow to evenly distribute the resins within.
  • Place pillow directly in FilStar filtration basket after (above) filter foams.
  • Activity of pillow lasts for 48 hours before recharging is necessary. It is recommended to maintain a GH above 50 ppm for optimal fish health.
Hardness Removal for Each 48 Hours of Use (1 filter pouch):
Aquarium Size (L/US gallons) ppm Removed
95/25 440
208/55 220
416/110 110


Use Aquarium Pharmaceuticals Test Kits to monitor water quality weekly. Water Softener Pillow is designed for use with other Filstar filtration media.

Directions for Recharging: Remove pillow and rinse in tap water. Make a recharging solution by dissolving 60 g (3 tablespoonfuls) of non-iodized salt in 210 ml (7oz.) of water. Place the pillow in solution for at least 2 hours for full recharging. Make a new recharge solution after 4 recharges.


Manufacturer Info

Aquarium Pharmaceuticals Aquarium Supplies
Aquarium Pharmaceuticals (API) has been helping people take good care of ornamental fish for over 40 years. Their research and development scientists have advanced the care of fish with all-natural medications, stable bacteria for biological filtration, one-bottle test kits, consumer-friendly dosing caps and much more. They’ve received over 25 global patents for their breakthrough innovations in the aquatics industry. And they continue to look for ways to improve the fishkeeping experience for hobbyists. Research. Experience. Dedication to scientific, quality treatment for healthy fish. It’s what makes API the first choice of aquarium owners. API manufactures and sells hundreds of products across many different product categories, including aquarium and pond treatments, aquarium equipment, aquariums and fish nutrition.

Do you have experience with Aquarium Pharmaceuticals FilStar Water Softener Pillow?

Write a Review