Natural mixed gravel graded at 4-6mm, in 5kg and 10kg bags. The grain size is the point: at 4-6mm water moves through the bed rather than sitting in it, so you get far less of the anaerobic pocketing that fine sand develops in a tank without much flow.
Allow roughly 1kg per 4 litres of tank volume for a 4-5cm bed — about 15kg for a standard 60-litre tank.
The same grain size that keeps the bed open also lets uneaten food fall out of reach, so vacuum it properly at water changes. And 4-6mm is coarse for corydoras and other fish that sift substrate through their gills; for a tank built around those, the finer multi brown gravel is kinder.
Features
- 4-6mm grade — open bed, good water movement, resists compacting
- Two bag sizes — 5kg and 10kg
- Natural stone — uncoated and undyed
- Inert — no effect on hardness or pH
Care
Rinse until the water runs clear before use. Vacuum between the stones at each water change — coarse gravel hides more than it looks like it should.
Also in multi brown and natural white. More in our Fish Supplies range.