Powerhead

[MikeWs Fish]

Hi guys, What would be the recommended flow rate to get water from water barrels into the tank and visa versa?

The water might have to travel against gravity for qa bit and i dont wanna be stingy on it because they are quite cheap. Any suggestions of brands and flow rates?

ta

[Josh]

The bigger the better. Remembering that the higher you go the lower the flow rate will be. As for brands, I dunno Its not going to be something that goes all the time so a top-of-the-line pump wouldn't be needed. But If you have got the money get a good one

[nannat]

id be looking for a pump using 70 watts or more.a resun king 4 is the smallest i use out of the few i have here.thats for 19 mm hose,heights of 2m and over.i guess a k4 or similar would reach the top of the rack youve got your eye on with a quick flowrate-from the floor it will stand on.that would need to be tapped back perhaps when doing cold water changes in winter.so i reckon if you consider the slow flow maybe needed on water changes,a king 3 will do the job at height of 2m.

you can compare other pumps if youd prefer a different brand to the resun statistics.

the pump that may have come with the racking may be the one to match to use the new as a backup if it stuffs up.or get one that gives the maximum flow through the pipes of your racksystem-then swap the one supplied with the racksystem as a water refill pump.

ive been told the length of the hose on the floor restricts flow also as per against a shorter hose

either way you should invest in a hoseline tap to regulate and switch off water flow,and a 19 mm hook pipe to keep the water going into the tank.if youre using a storage drum you are all set.

[MikeWs Fish]

Thanks Nathan.

Could you please explain the last paragraph in more detail? I'm very very newb to any sort of sytem which isnt a straight up tank with an internal or external canister.

ta

[mianos]

They key thing to take note of is the 'lift', 'head' or maximum hieght the pump will push the water. Many pumps will have a graph on the side showling the flow rate verses the lift. The higher the lift the slower the flow rate. Ideally you should go for a pump that has at least 1 metre higher lift than you need, better still even more. Once you have the lift it's a pretty simple matter to restrict the water flow if it is too fast. (Contrary to popular opinion, centrifugial implellor pumps have no issues being restricted as long as they are not stopped).

- edit: spelling mistakes

[nannat]

what i mean by max flowrate is this.

using an existing pump to see how much water is above the point of waterfall of your piping outlet.the amount excess water that drained and sits in your sump when power is off is the amount of water that is above the level of waterfall over your piping outlet.these two are the same volume in retrospect of the more water your pump flows out the sump return the more chance there is of your pipes not being large enough diameter to return that tank water level increase until the tank overflows.

or this way,(easier i reckon as its a comparison of small versus large volume)

a smaller volume pump barely flows over and trickles down a pipe outlet return to the sump.this small volume of 'water in motion'as i call it barely raises the water level when it drains to the sump when power is off.

while a larger volume pump rushes water over the return pipe outlet and gushes down to the sump.which considerably raises the water level in the sump when power is off.

beware though the amount of 'water in motion'can over flow your sump if the sump is too small.or can over flow the tank if your pipe return are small or RESTRICTED.by this i mean using plastic gauze or screen (essential)to prevent fish from 'piping' or excess food or debris gunking on the screen.

i was suggesting if your buying a new pump,to get get one to maximise waterflow through your system and how it can be too small or large in volume.this gets you a newer more reliable pump,leaving the old one for waterchanges.

gee i hope this explanation helps,mike.its something understood easily when seen tho.

just think how much "water in motion" sits in a sump as relative to the thickness of water FALL down a pipe.logically water can only fall down a pipe of diameter -it cant "wave" up and over it.the maximum a pipe can take will "whirlpool" water down,but a sump needs to be big enough to hold it when power is out.

[MikeWs Fish]

Thanks nathan makes perfect sense! (i think)

So ideally, i need something with a similar or exactly the same water flow as what was being used before.... or I could get more powerful one and testing the effects different water flow rates from the pump have on the water level in the sump. If it is too powerful and there is too much water in the sump at one time, restrict the power?

[nannat]

mike,get the system running and see the level of water over the return pipe.concentrate on this rather than the sump.

after you fill the tanks the sump needs to be filled way over the height of the pump as extra water is needed for the pump hoses and extra water over the pipe return.the total surface area of water is falling out a small hole in the corner and is slow to do it.as its small the pump increases the level of water in the tank.until it stops and it drains evenly but the level stays above the return pipe which is way smaller in diameter area than the surface area of the tank..

so it overfills over the level of the pipe and stays at that level all the while the pump is running.this extra fill water increases the depth required in a sump.

i havent done it myself yet mike,but i reckon a sump can be built to a greater height using extensions of glass on the inner walls.the water force pressure at the surface of a tank is lesser than at the bottom.

water needs to fill a tank ABOVE the return before it drains.it can drain at a rate determined by the diameter of the return pipe.it needs to break surface tension and spill slowly over the return pipe as it starts to drain.the rate it spills over the pipe and actually falls is an act of gravity and can not be adjusted.the rate a tank fills before it falls can be adjusted by the volume of pump flow.a higher volume pump fills the tank to a *height of more volume* than a pump of lower volume does when the excess water is being drained.this just happens that way i think as gravity and fall stay the same against the filling of the tank.this is seen to be believed so dont worry mike,i couldnt imagine it from description and theory either.you can check out using higher volume after your running your system.

if there is 1 cm of water over the pipe when the system is running-your flow is IMO adequate.this can be increased a lot if you use a higher volume pump though-up until the when water gushes down after a "whirlpool"is over the pipe return.and something like 2 cm of water or more is building up over the pipe height but it will be draining out safely.

interesting what mianos said regarding tapping back a pumps excessive flow-in these terms the flow can be adjusted back from a 'just a bit too large' volume pump to give the safe maximum flow.

[MikeWs Fish]

Thanks for taking the time to explain it, Nathan! I get it now.. Ta.