Just a point on filter start products, they sit on dealers shelves for X amount of time(years) and then some one comes along buys it and put's it in a tank. If there is anything of any use left in there it'll do nothing to hardly anything for a tank let alone a pond.
EA have just brought out pond pure which is balls of 8mil bacteria in a ball, it's only been out a couple of weeks and does have an expiry date on it but again I still can't see how it would work, what are they feeding on in this ball?, I am willing to be proven wrong on this.