Neptune DOS problem

[Miller535]

Has anyone had any issues with getting their DOS to dose small amounts? I recently set one up. I dose 65ml of 2 part a day. I set it up to dose calcium over an 8 hour period while my lights are on. And Alk the other 16 hours. With the Alk spread out in such small doses, nothing comes out of the tube. The head slightly turns on but nothing comes out. Now if I have it dose over 8 hours where a larger amount is set to come out, it works fine. It's like it can't dose small amounts. Anyone else have this issue?

 

[SuncrestReef]

You likely have an air leak in your tubing connections. Have you tried a calibration to see how much it’s actually pumping?

 

[Miller535]

You likely have an air leak in your tubing connections. Have you tried a calibration to see how much it’s actually pumping?

Yeah. If I calibrate it it works just fine. If I hit the prime button it comes out fine. Like I said, if I set it up where it's dosing a larger amount, it works fine. It only doesn't work when I have it dos small amounts. The head audibly doesn't even turn on as loud.

 

[SuncrestReef]

Yeah. If I calibrate it it works just fine. If I hit the prime button it comes out fine. Like I said, if I set it up where it's dosing a larger amount, it works fine. It only doesn't work when I have it dos small amounts. The head audibly doesn't even turn on as loud.

Since the DOS splits up the total volume over the interval duration, the head will turn less per dose on longer intervals, and it also turns slower which makes it less noisy. That part is all normal.

Have you considered placing the tube into the calibration cylinder to measure the total it actually dosed during the whole day? My guess is that due to capillary action, some of the time the liquid won't dispense as a meniscus builds up, then on a subsequent dose extra is released, so overall the correct volume is dispensed.

 

[Miller535]

Since the DOS splits up the total volume over the interval duration, the head will turn less per dose on longer intervals, and it also turns slower which makes it less noisy. That part is all normal.

Have you considered placing the tube into the calibration cylinder to measure the total it actually dosed during the whole day? My guess is that due to capillary action, some of the time the liquid won't dispense as a meniscus builds up, then on a subsequent dose extra is released, so overall the correct volume is dispensed.

I did consider that. But I measured my DKH the next day after I installed the DOS, and my DKH dropped like it has not been dosed at all. So that night I watched it the first several times it turned on and nothing came out. When I changed the intervals to 8 hours instead of 16 hours, it worked fine.