I've been using them for years. They work. Tip: don't throw them away. Wash them off in tap water; soak them in a solution of white vinegar (10:1); let them dry. I now just wash them off and the same piece of wood works fine. Superglue (Gorilla) plastic case in stone for a tight seal. Connect them to your airline before loading them; run for 15-20 seconds; then put them in the water. DO NOT scratch them with a knife. Another reviewer recommended this. I tried. All it does is shorten the life of the stone by cutting away the wood. I get perfect rinsing/drying results. I have about six of these that I rotate throughout the year. I can replace one or two a year. I use them in a protein skimmer.
Aquael Fan Filter Mikro Plus
35 Review
KEDSUM 330GPH Ultra Quiet Submersible Pump With High Lift And Grounded Power Cord - Ideal For Fish Tanks, Ponds, Aquariums, Statuary, Hydroponics - Includes 3 Nozzles And 1500L/H Water Flow
39 Review
KEDSUM Quiet Rechargeable Battery-Operated Aquarium Air Pump With Dual Outlets - Perfect For Fish Tank, Outdoor Fishing, Transport, And Emergencies
28 Review
Humidifier / air purifier "Fanline Aqua VE400" with an ionizer, with a capacity of 410 gr/h
44 Review
๐งฒ Efficient Magnetic Fish Tank Cleaner: KEDSUM Floating Clean Brush with Handle Design
34 Review
Efficient 2-In-1 Magnetic Fish Tank Cleaner With Non-Slip Design And Scratch-Free Blades
37 Review
Jasonwell Magnetic Aquarium Fish Tank Glass Algae Cleaner - Floating Brush (L Size)
37 Review
Vacuum cleaner TEQQO Aquastick 3 in 1 Power, grey/turquoise
26 Review