You are actually supposed to add fresh the water when you vacuum the bottom. I don't understand why you would want to put the dirty water back in. This is known as doing a water change and most successful aquarists do this weekly or even more often. It's usual to remove between 20% and 50% of the water each time and replace it with fresh dechlorinated water. This not only removes visable soil from the gravel, but lowers the nitrates and removes free floating, potential harmful bacteria.
Since a Gravel Vac is based on the principle that siphons pull with more suction the lower the bottom end is, if the tank is low to the ground, it's to be expected that the Gravel Vac will not work as well as one that's higher up. A good solution to that problem is the Python which is attached to a faucet and the water and dirt is removed from the tank by the force of the running water. When the tank is adequately cleaned and drained, it can be refilled by just twisting the bottom of the Python and adjusting the water temperature. Chlorine/chloramine remover can be added directly to the tank.
http
/www.pythonproducts.com/nospill.htm
Since a Gravel Vac is based on the principle that siphons pull with more suction the lower the bottom end is, if the tank is low to the ground, it's to be expected that the Gravel Vac will not work as well as one that's higher up. A good solution to that problem is the Python which is attached to a faucet and the water and dirt is removed from the tank by the force of the running water. When the tank is adequately cleaned and drained, it can be refilled by just twisting the bottom of the Python and adjusting the water temperature. Chlorine/chloramine remover can be added directly to the tank.
http
/www.pythonproducts.com/nospill.htm
