Do canister filters lose flow with head?
- Thread starter fhawk362
- Start date
I<3fish;3926859; said:
but you see thats only a single initial prime.. if you unplug ur canister right now i can guarantee the water level in the tube will be no lower than the water level (assuming the canister is filled and sealed) in the tank
That is true but their is still going to be some loss fighting against gravity, maybe not as much as other pumps, thats what id like to find out
I<3fish;3926859; said:
No. There's no loss from additional head height.
Maybe it will help if you think about it this way:
Since the canister is a closed, sealed system, the weight of the water in the intake hose is pushing up on the water in the outlet hose. The forces balance out, and there's no additional resistance from gravity.
fhawk362;3927019; said:
If both your intake and output tubeing's highest points are level and the same length the "head space" (and thus GPH loss) will be negated by the gravity feed effect of the intake. Thats why when you kill a canister it dosent have any back flow, gravity will exert the exact same force on 1/2g of water in the intake tube @5ft height as 1/2g of water in the output tube @5ft. So with the gravity exerting the same force on the intake as it is on the output should make "head space" a non issue. However im sure the ammount of filters out there that have the exact same length of tubeing on both intake/output is minimal, but considering most are pretty darn close I'm willing to be the loss's are miniscule at best. Most if not all of the flow loss in a canister filters "flow rate" is going to be cut down by the filter media.
it is just like in a car the speedo in a car is upto 10% slower then the speedo so if you got a ticket and the speedo of a car said you were doing the speed limit the manafacturer is lieable.
it is the same with pumps it may say 2000 gallons per hour but it might do 2200.
in conclusion your pump should be doing about what it says it does.
it is the same with pumps it may say 2000 gallons per hour but it might do 2200.
in conclusion your pump should be doing about what it says it does.
you still have to fight gravity, it is easier to pump water in that vacuumed state with the water level being high but you still have to do work to move water in the hose. The water doesn't want to move.
also head loss takes into account friction in the hose.
you can go to homedepot and buy 20 feet of hose to test it out.
also head loss takes into account friction in the hose.
you can go to homedepot and buy 20 feet of hose to test it out.
that is true aswell.
but i was saying that the pump will usually do more flow rate than they are said to do.
(its a complicated marketing thing)
but i was saying that the pump will usually do more flow rate than they are said to do.
(its a complicated marketing thing)
mgk;3927359; said:
since we can all agree that sumps lose flow with head height i will use that as an example...
a sump pump needs to work 100% against gravity because it is the only thing pushing the water up to the tank..
a canister doesn't.. the vacuum in the canister allows for the water to be pushed up to the waterline thus making the pump have to work less.. at any height below the tank's waterline the sump will always have to work to push the water in the tube up to the tank, but the pressure from the inlet will always be counter acting the difference in the output..
if you look at a u shaped tube u can see what im talking about.. no matter how much u fill it the water levels will always be equal. if desired ill even take a video of my canister's outflow as i move the canister up and down.. the flow rate wont change..
