coffeetwitch
Aquarium Advice Addict
Because the 3/4 is under pressure and the 1" is gravity feed.
coffeetwitch said:Because the 3/4 is under pressure and the 1" is gravity feed.
coffeetwitch said:An to add to mr_x. CPR overflows are rated by the bulkhead in the bottom of the box. The 600 gph has a 1". The next size up 900? Has 1.25? If I recall properly. That's what he was trying to tell us off the lifereef site correct?
Stop over thinking this and base or decisions off of those predetermined flow rates from manufacturers?
Sorry I can't give you flow rates but, I do understand fluiddynamics a bit. In fluids the base line from a pressue standpoint is inches of water column. In otherwords, in a column of water X inches high you will get a pressure at the base of Y lbs per sq inch. Increase the height and the pressure at the base increases At only a couple of inches, under gravity, a certain pipe will flow say 25 gallons an hour. If the intake to that pipe is rased to a few feet, the pressure will increase and the pipe will flow say 50 gallons an hour. Now, if you have a certain flow and you change the pipe sizes it will change the pressure at the discharge. When you hold your finger over the end of the hose the same amount of water at the same pressure is coming in from the faucet but the pressure at the discharge goes way up because the same amount of water has to go through a smaller opening.
So, since the pump is pushing the water out under pressure, it can use a smaller size pipe then the drain line. The drain line only has the pressure created by the differance in elevation between the tanks water level and the sumps water level. Less pressure means the pipe has to be bigger in order to flow the same amount of water as the pipe under pressure.