I'm not familiar with that specific potting soil but if its got any fertilizer at all you wont want to use it. Also if it's got those little white bits in it you won't want to either. From the picture it says 'feeds plants up to 6 months' so that would make me think it has fertilizer in it.
Either look for 100% organic potting soil or just plain old topsoil with no added anything.
Another tip I've heard is if you don't fertilize your lawn and you've got spots where water collects when it rains then to dig there because it is full of clay which is great for planted tanks.