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Aqua one cannister filters?


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I don't like my EHIEM 2213. Then again, the previous owner had been running it besides the tank without a decent head height. Replaced the hoses to give it a decent head height(the ones he had were very short) and its just as useless.

You can't change head height unless raise the outlet above the water. And any head height at all makes a lot of splashing and decreases flow.

Now, if you're talking about the physical distance of the cannister below water level, that's not head height. But I can't see why that would make a difference. The extra water pressure might minimise cavitation a little but that's nowhere near an issue with these kind of pumps.

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You can't change head height unless raise the outlet above the water. And any head height at all makes a lot of splashing and decreases flow.

Now, if you're talking about the physical distance of the cannister below water level, that's not head height. But I can't see why that would make a difference. The extra water pressure might minimise cavitation a little but that's nowhere near an issue with these kind of pumps.

For some reason i thought head height was how much it could travel upwards. My bad! Yeah i lowered it even more. P44 said it was gravity powered or something and i had been ruining it by running besides the tank

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For some reason i thought head height was how much it could travel upwards.

It is, but with a canister filter if the intake and return are at the same height (as they are when they go over the back of the tank side by side) then you have a zero head height, even if the canister is a metre below the tank.

For the record I currently run two aqua ones and two via aquas, they all do their intended job and were good value for money as cheap second hand items. But money aside, there is no doubt in my mind the Eheims are a better product.

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For some reason i thought head height was how much it could travel upwards. My bad! Yeah i lowered it even more. P44 said it was gravity powered or something and i had been ruining it by running besides the tank

It how high it can pump the water upwards above the SOURCE water level. It's the difference in heights between the intake water source(the top of the water in your tank) and the outlet water.

So if your spray bar is under the water your head height is 0. That's because there is no height difference between the surface of the water in your fishtank and the surface of the water in your fish tank. The weight of water pushing down the intake matches the water pushing down the outlet. So there is no weight of water that the pump has to lift.

If you raise the spray bar a foot above the water then it's the difference between the surface and the outlet. The pump has to lift the water that extra amount requiring more energy and decreasing flow.

If you put the spray bar outside the tank and below the water leven then it's operating at a negative head. You have more pressure pushing down the intake than you have the weight of the water in outlet pushing down. So you have water pouring out, that's what makes a siphon work.

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I beg to differ Ira.

Head height is the difference between the intake and the outlet.

So if your tank is 700 high and your intake is at the bottom of the tank and your outlet is 100 below the top of the tank, then you have a head of 600

Lol, no. The inlet and outlet location is irrelevant, it's the water levels that mater.

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the water flows up the pipe by itself ie: water level

then the pump takes over

just like syphoning tank water it wil flow downhill

but as you lift end of pipe it will only floww when below level of tankwater

after that to lift water higher than tank level requires a pump

hence head height is any thing above level of water in tank

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So the pump is only used for the last 45cm or so?

Apart from the fact that this works in concept because of the whole gravity and equilibrium and all... but isn't accurate as far as our cannisters are concerned because the pump is constantly on and does physically push water up on its own irrespective of where the inlet is.

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Not if you put your finger over the top of the straw and create a pressurised system :wink:

If you do that to your canister its not going to flow very well!! :P

Stick your siphon hose 2cm into the water and suck on the end, then stick it all the way to the bottom and suck on it and see if there is a difference.

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