I haven't heard of it. Looking for it on google showed some UK websites, I take it that's where you are from? If it is anything like similar products here in the US, you need be careful not to overfeed, and it might also be beneficial to shut down your skimmer for an hour or so after feeding.
great call law. that product label sounds like a play on "gammarus" which is common in reef terminology so maybe it's made from grinded up refugium shrimps! lol that doesn't mean it's a bad product either, just guessin