Hobby Angular Airstone - M (2PCS)

Hobby Angular Airstone is an angular block airstone in three sizes. The flat faces mean it sits where you put it instead of rolling about the way a round stone does.

Key Features

• Three Sizes: Medium is a two-piece pack of 3x1.5x1.5cm stones; Large is a 2.5cm cube; Extra Large is 5x2.5x2.5cm for bigger tanks.
• Fine Bubbles and, per Hobby, a long service life.
• Sits Flat, so it stays put under the substrate line or behind decor.

What Aeration Does, And Does Not Do

• It mostly works by moving the surface. Gas exchange happens at the water surface, not on the bubbles. A bubble stream drags water up to the surface and that is where the oxygen actually gets in.
• It matters most in warm water. Warm water holds less dissolved oxygen, so a tank at 30C needs more surface movement than the same tank at 24C. In a UAE summer that is not a small effect.
• It does not cool the water. In UAE summers the problem in most tanks is too much heat, not too little. Aeration helps a warm tank because warm water holds less oxygen - but it does not cool it. If your tank runs above about 30C you need a fan or a chiller, not more air.
• It does not replace a filter. An airstone oxygenates; it does not remove waste.

Good To Know

• Pick the size above.
• You need an air pump and airline, and neither is included. This is the diffuser only. A non-return valve or a pump mounted above the water line also stops water siphoning back into the pump if the power goes off.
• Airstones clog. When the bubbles get coarse or one-sided, soak the stone in a weak vinegar solution, rinse it well and refit - or replace it, they are cheap.
• Mount the pump above the water line if you can. Then even without a valve, water cannot siphon back.
• An air pump buzzes. Standing it on a folded towel rather than a hard shelf makes more difference than any anti-vibration gadget.