That is good you got alot of the stuff out, bet there is alot more in there. Those vacums are really cheap and so worth it. The pic above shows what they look like, its just a bigger tube with the hose attached to it. It works so well in gravel as it sucks up the gravel to a point but all the stuff in that gravel is what is sucked out, they are great. If you have sand then you have to be careful as it will suck all the sand out too. I have had the same vacum for years, just about time to replace it, they are the best tool you can have with gravel bottoms.