Do some gravels clean better than others? As much as I tried, I never could get the gravel in my old tank clean. And Im skeptical to put it in new tank.

What is your definition of clean? Use a gravel vac and push it into the gravel so you actually touch the glass. The water will swirl around in the vac,wait till it clears and then repeat the process.Gravel is much the same, you obviously get different grades but it's not difficult to clean. If you are setting up a new tank, then just get some new Gravel, it doesn't cost very much money.

Let me put it like this. Every 3-4 days i would vaccum gravel until about 20% of water was gone. And I was pushing vacuum all the way down to the glass. I did notice that when I lengthened the hose and ran it outside and down a hill, that the vacuum pulled much harder and cleaned better. Maybe that was the problem all along.

hey jayman, your technique is exactly the same as how i clean my gravel, and it does make a big difference with that extra suction! i just taped the outlet hose of my gravel vac to a long piece of old garden hose and run it out the window and down the hill towards the lake in the back yard lol. works great.

Aggreed! I got fed up with vaccuuming my 90Gl because it was slow.
Now i put the hose in the garden instead of the sink.
3 feet more difference in level did the trick!

Pressure increases with height. The bigger the difference between the height of the water and the end of the tube the greater the suction and thus cleaning power