Duel headed peristaltic pump tubing

[LadyTang2]

When using a pump w 2 heads, does it matter if the lengths of line are different on the different heads, one 4 times longer than the other? The only difference would be whats left in line when it stops which is not much, or do I have that wrong? Does height of where tubes pull end matter? AGain on same pump, just duel head.

 

[Biglew11]

it does matter. the longer line creates higher back pressure (head height) the pumps will pump slightly different amounts. if you're just using for dosing pumps it doesn't matter that much. if you're using them for auto water change setup then it will matter.

if this is a single motor driving two heads at the same time then they will pump the same, the head with the longer line will still cause the motor to spin slower so this will decrease the amount pumped. but it will still remain the same on both heads .

 

[LadyTang2]

it does matter. the longer line creates higher back pressure (head height) the pumps will pump slightly different amounts. if you're just using for dosing pumps it doesn't matter that much. if you're using them for auto water change setup then it will matter.

if this is a single motor driving two heads at the same time then they will pump the same, the head with the longer line will still cause the motor to spin slower so this will decrease the amount pumped. but it will still remain the same on both heads .

Thanks, this is one motor spinning two heads, so exactly the same amount of liquid will come through even though one of the heads is contributing more to the slowdown, its the slow down of both heads right? So basically there is no worry if its one motor on two heads, do i have that right?

 

[Biglew11]

correct

 

[92Miata]

Thanks, this is one motor spinning two heads, so exactly the same amount of liquid will come through even though one of the heads is contributing more to the slowdown, its the slow down of both heads right? So basically there is no worry if its one motor on two heads, do i have that right?

It really comes down to whether or not the pump is designed correctly. The entire point of medical peristaltic pumps is that they're fixed displacement. X rotations gives you X*someConstant ml of fluid. With reef grade pumps, who knows.

There are two things to be aware of -
1: some reef dosing pumps are not true peristaltic pumps - and will allow fluid to leak back through them. All bets are off in this case.
2: The calibration coefficient of the two pump heads may not be exactly the same. (IE, the rollers may be off from each other by a fraction of a millimeter, etc). This shouldn't be a big deal, but you may find that for every 1000 ml pumped by one head, you only get 998 ml of the other (or something like that).