i went and got some sand for my 100 gallon tank today, only 50 pounds, got 2 bags of salt and some water conditiner cost 100 dollars i dont think that was bad, any who, that guy told me that a rena xp3 first of all in not worth the money and that being rated for 175 gallons and my tank being 100 gallons its way under rated for my tank, and i should buy 2 more canisters and at least have a rated 500 gallon filtering capacity for a 100 gallon tank!!! do i walk around with a sing that lights up and says idoit on it? what would you guys recomend for a 100 gallon tank, like i said i have a rena xp3 and have a hot filter also rated for another 100 gallons is this enough or do i need more canisters?