there is little difference. Pond matrix is larger in size and matrix is smaller in size. Pond matrix may have a larger sa/vol ratio but if you used normal matrix you could fit more in there =P
one way or another they both work great. the difference is minimal if you have a large sump to fill Id go pond if its a canister I would use which ever one is cheapest and you can get with ease.
one way or another they both work great. the difference is minimal if you have a large sump to fill Id go pond if its a canister I would use which ever one is cheapest and you can get with ease.