Zeolite is available in a gravel size or in a sand form, it is a naturally occurring volcanic rock that acts as a nutrient exchange, it absorbs minerals and nutrients, including ammonia (fish wastes and the byproduct of decaying matter), it will store these captured nutrients within the cells and will release directly to the root system of the plants as required. It works equally well in soil as it does in water. It can be mixed directly into the soil to maximise nutrient retention, act as a growing bed for vegetable seedlings in aquaponics and zeolite is great for controlling algae. Castle Mountain Zeolites are Australian and widely considered the best available Zeolite in the world.
Spongolite is a naturally occurring fossilised sea sponge, it holds nutrient and water, it is unique in that is does not leech the held water, it will only release to the plant root system on demand, again making it a valuable addition to any soil, garden bed and again in aquaponics. Spongolite is mined in Western Australia.
Both Spongolite and Zeolite are natural, certified organic and endorsed by the Water Corporation of Western Australia as a preferred soil amendment. There are suggested guides for rates of application, for lawns, gardens, algae control, even top dressing for synthetic turf (to eliminate smells),but you can be assured that you can never overdose, using more will always be better.