Dual pump wont dose equel amounts

[TracyZeuner]

I have the dual head pump and I'm trying to set it up to dose my 2-part solution. Right now I am just setting it to dose for x number of minutes till I get the amount of mil I need. The problem is that the heads are dosing different amounts of liquid. I set it up yesterday to run for 7 min per hour for 24 hrs and when I measured the amount of fluid, 1 glass had 175mil and the other one had 200mil. Why is this happenning? Does it have to do with the length of the tubing running from the heads. I have the 2-part dosing into different sides of my sump, so one tube is longer then the other.

[Snarkys]

one tube may have been empty when you started . try again and see what happens

[TracyZeuner]

So the length doesnt matter? Should I just run the pump until fluid flows out both sides and then start to use?

[Snarkys]

it shouldn't matter once they are fully primed.

if they are nor primed it will take longer for the longer one to get water up to the pump and it takes longer for air to form enough suction to get the fluid up there.

[TracyZeuner]

The lines running up to the pump are the same length. I ran the pump for 1 hour and measured the fluid in each glass. 1 was 80mil and the other was 70mil. The shorter hose is conected to the front pump and the hose that is longer is hooked up to the back pump. The longer hose goes to the back of my sump and the shorter hose to the front. The longer hose is only longer by about 6in. Any ideas as why this might be happening?

[Snarkys]

I'm asking my supplier about it now .

[TracyZeuner]

Even if they pump the same amounts, .75mil @ 1 hour(60min) =45mil. This is first time at trying to dose using a pump so Im sorry about all the questions.

[Snarkys]

they told me flow rates listed are nominal and will vary depending upon fluid viscosity and back pressure.

still asking why one head is pumping more than the other.

[TracyZeuner]

Thanks for the help and the quick responce. I have tried it at many different times and the ratio is always the same, so it is consistantly the same amount off

[Snarkys]

can you switch the fluids and see if you get the same results from the same line . this would rule out the fluid as the cause of the problem and pretty much assume that the inside diameter of one of the tubes must be off a bit.

[TracyZeuner]

I will try that out and let you know. Right now it draws from the same fluid container. It is just in some R/O water till I figure out the amount I need. The tubing was 1 10 foot length I got from you guys.

[TracyZeuner]

I swithed the tubes from front to back and still got the same results-one was122mil and the other was 142mil. I have now cut the tubing that goes into the sump tha exact length and am running another test to see if that was the problem. I have watched the pumps turn and it seems they turn the same amount. The only other thing I can think of is maybe the tubing inside is different, but I have not changed it, it has the tubing that came with the pump.

[TracyZeuner]

OK- this was the last test.
I cut all the hoses the same length and this is what I came up with: front pump-135mil
back pump-112mil

[Snarkys]

ok

email me your address and will send you two new tubing sets , I'm sure this is the issue .

Ryan@reefchili.com