Neptune Apex DOS problems

jaws789832 · Mar 15, 2017

So I have 2 DOS pumps and am dosing the triton Core7 which requires all 4 pumps. Problem is 3 of them are working great and one is allowing air to bleed back up into the line, so when it comes time to dose that one it doesn't drop any fluid. I replaced all the tubing twice, Made sure all the air was bled out of it, calibrated it, made sure all my fittings were tight (many times due to changing out the tubing). The first pump I purchased a while ago and it is working fine, the problem pump was purchased about 6 months ago when I switched to triton. Anyone else ever had this problem? I am going to try to get a new pump head to see if the air leak is in the pump somewhere but after that I am at my wits end. Its kind of a pain because I have to go in and manually dose that pump whenever I see the levels in my dosing containers are different. I know I am adding around the same amount over time but my tank is getting a blast of 3a all at once and I really have no idea how much I am dosing at that point. I just hold the button until I see fluid come out and give it a pretty good shot until the levels match.

Brew12 · Mar 15, 2017

jaws789832 said:
So I have 2 DOS pumps and am dosing the triton Core7 which requires all 4 pumps. Problem is 3 of them are working great and one is allowing air to bleed back up into the line, so when it comes time to dose that one it doesn't drop any fluid. I replaced all the tubing twice, Made sure all the air was bled out of it, calibrated it, made sure all my fittings were tight (many times due to changing out the tubing). The first pump I purchased a while ago and it is working fine, the problem pump was purchased about 6 months ago when I switched to triton. Anyone else ever had this problem? I am going to try to get a new pump head to see if the air leak is in the pump somewhere but after that I am at my wits end. Its kind of a pain because I have to go in and manually dose that pump whenever I see the levels in my dosing containers are different. I know I am adding around the same amount over time but my tank is getting a blast of 3a all at once and I really have no idea how much I am dosing at that point. I just hold the button until I see fluid come out and give it a pretty good shot until the levels match.

Without seeing it in person I can't say for sure, but I think I understand your problem.

The rollers in the peristaltic pump the DOS uses need to completely pinch off the tube and that doesn't seem to be happening. I am guessing you have the discharge of the pump higher than the dosing container. When the pump stops, the fluid drains back down into the container which sucks the air up. There is an easy way to confirm this. Place a container of water higher than the level of the pump and put the suction in this one. Discharge the water into a container lower than the level of the pump. Let it completely fill the line. I expect you will see that flow continues to trickle when the pump stops.

Your new pump head should fix this problem. I don't know if there is any way to adjust the rollers without replacing the head.

jaws789832 · Mar 15, 2017

Thank you Brew. What you described is exactly what seems to be happening. To confirm it I will try what you said and see what happens. I didn't want to take anything apart until the new heads arrive because I have a tendency to break things LOL, but raising my dosing container up would tell me if this is the case.

Doug B · Feb 25, 2018

Old thread, new problem. I had 2 DOS and DDR combos on my reef tank. All setup and running fine until I noticed this evening that the ALK was low. So after some investigation I determined that the DOS' are not dosing. Only one of the DDR units shows up on my dashboard. I set the DOS to dump 100ml in 10 minutes starting 1 minute from now...and nothing happens. I have done everything I can think of, including a factory reset of the entire APEX. I'm at my wits end. I am even having an issue where the apex dropped connection 10 times in the last 24 hours, even though it is wired in to the network, and sitting next to another apex on another tank, which is running just fine. I'm about to throw a couple grand worth of tech in the trash...

Brew12 · Feb 25, 2018

Doug B said:
Old thread, new problem. I had 2 DOS and DDR combos on my reef tank. All setup and running fine until I noticed this evening that the ALK was low. So after some investigation I determined that the DOS' are not dosing. Only one of the DDR units shows up on my dashboard. I set the DOS to dump 100ml in 10 minutes starting 1 minute from now...and nothing happens. I have done everything I can think of, including a factory reset of the entire APEX. I'm at my wits end. I am even having an issue where the apex dropped connection 10 times in the last 24 hours, even though it is wired in to the network, and sitting next to another apex on another tank, which is running just fine. I'm about to throw a couple grand worth of tech in the trash...

Sounds like you may have a ground developing in your USB cables. Any signs of corrosion at any of the connection points?