APEX DOS , does it have to be mounted higher than water source?

scott11106 · Dec 11, 2020

sorry if this is a stupid question,

I feel I am pretty good with apex gear but I have a new DOS and setup to do a water change, I mounted it lower than the tank (no sump on this system) and it keeps loosing the prime to remove the waste water. I pulled off the source water line from the tank and it flows water telling me there is a syphon occurring but i would think that would help it to work properly. anyway it is not removing the wastewater and before I remount in a new location which is not desirable i thought i would throw it out there.

maybe i am missing something?

Brett S · Dec 11, 2020

The DOS will be fine above or below the water source. Frankly peristaltic pumps don’t really even need a prime as they are capable of moving both water and air, so I’m not sure that losing prime is actually your issue.

I‘m still not totally clear on exactly what’s happening. How exactly are things connected and how long are the tube runs? When you say that it’s not removing waste water from the tank, how do you know that it’s not?

The other thing of note is that when you follow the neptune instructions for setting up AWC with a DOS they tell you to connect the waste water lines ‘backwards’ so the line going into the tank connects to the ‘out’ on the pump head and the line going to the drain connects to the ‘in’ on the pump head. This works because the pump will run in reverse when the AWC program runs. However, if you are trying to prime the lines with the button on the pump it will run the pump forward, so it will try to move water from the drain to the tank. If you are trying to prime it with the button then this could be your problem.

Post some additional details about exactly how you have things set up and I’m sure we can get it working.

SuncrestReef · Dec 11, 2020

Brett S said:
The other thing of note is that when you follow the neptune instructions for setting up AWC with a DOS they tell you to connect the waste water lines ‘backwards’ so the line going into the tank connects to the ‘out’ on the pump head and the line going to the drain connects to the ‘in’ on the pump head. This works because the pump will run in reverse when the AWC program runs. However, if you are trying to prime the lines with the button on the pump it will run the pump forward, so it will try to move water from the drain to the tank. If you are trying to prime it with the button then this could be your problem.

See my post about reversing the DOS tubing for AWC to facilitate priming and calibration of the DOS:

Finally got a DOS for AWC’s! Any tips or hints appreciated!

Well after a long wait, DOS has arrived at my house! I’m reading through the directions and things seem pretty straightforward, but R2R members always seem to know tips that aren’t in the directions. I have a 40g breeder with a 20g sump. I have an Apex Jr with room for the module and a surge...

www.reef2reef.com

Also, if the tubing is losing prime, heat the tubing in hot water or with a hairdryer to soften it before connecting it.

scott11106 · Dec 11, 2020

Brett S said:
The DOS will be fine above or below the water source. Frankly peristaltic pumps don’t really even need a prime as they are capable of moving both water and air, so I’m not sure that losing prime is actually your issue.

I‘m still not totally clear on exactly what’s happening. How exactly are things connected and how long are the tube runs? When you say that it’s not removing waste water from the tank, how do you know that it’s not?

The other thing of note is that when you follow the neptune instructions for setting up AWC with a DOS they tell you to connect the waste water lines ‘backwards’ so the line going into the tank connects to the ‘out’ on the pump head and the line going to the drain connects to the ‘in’ on the pump head. This works because the pump will run in reverse when the AWC program runs. However, if you are trying to prime the lines with the button on the pump it will run the pump forward, so it will try to move water from the drain to the tank. If you are trying to prime it with the button then this could be your problem.

Post some additional details about exactly how you have things set up and I’m sure we can get it working.

yes, thank you for the refresher course, i did do that and that is why it is not removing the waste as i celebrated. let me try that and see but i am sure that is what is going on.

That is why i love this forum, fast and reliable help...

thanks again

scott11106 · Dec 11, 2020

SuncrestReef said:
See my post about reversing the DOS tubing for AWC to facilitate priming and calibration of the DOS:

Finally got a DOS for AWC’s! Any tips or hints appreciated!

Well after a long wait, DOS has arrived at my house! I’m reading through the directions and things seem pretty straightforward, but R2R members always seem to know tips that aren’t in the directions. I have a 40g breeder with a 20g sump. I have an Apex Jr with room for the module and a surge...

www.reef2reef.com

Also, if the tubing is losing prime, heat the tubing in hot water or with a hairdryer to soften it before connecting it.

yes, i forgot i had to go into the interval and set it to add, not remove. that way it worked the same as calibration and pulled from the left side of pump...clockwise.