Help with DOS for water changes

Mr.BobDobalina · 2026-10-19T07:48:22-0400

I am at a loss with this thing. Bout ready to throw it in the trash. Yesterday I came on to find out why my manual WC wasn't working. Got it going and it went all day. This morning I set it up to do another and for some reason ithe 1st pump for adding new water switches to removing water after 1 cycle. Why are these so finicky?!

Mr.BobDobalina · 2026-10-19T10:38:18-0400

Mr.BobDobalina · 2026-10-19T10:38:53-0400

In case anybody can help with the screens above. TY

n2585722 · 2026-10-19T20:00:48-0400

#apexusers is there someone that can help with this issue?

dangles · 2026-10-19T20:21:18-0400

Is there any reason you aren’t just doing continuous small daily exchanges? I have mine set to exchange 2.5 gpd just during daylight hours. Haven’t had any issues.

Mr.BobDobalina · 2026-10-19T21:09:59-0400

dangles said:
Is there any reason you aren’t just doing continuous small daily exchanges? I have mine set to exchange 2.5 gpd just during daylight hours. Haven’t had any issues.

I was using auto at 2% for the past 2 weeks and that's the plan for the future, but I have added a bunch of live rock so trying to do 10% a day for a few days.

Mr.BobDobalina · 2026-10-19T21:13:17-0400

In an attempt to figure out the problem, I noticed my drain line was sucking air today. I switched the hoses on the drain side and it started working on that end. Yesterday, the hoses were reversed and it worked perfectly. This thing is possessed!

Tangdora · 2026-10-20T01:18:38-0400

if you don’t want to use the interface to control your dose. Set a profile and directly specify the direction you want the pumps to run. Then call the profile rather then just calling THEN ON

There is also a WC task option that will set up the commands for you.

Mr.BobDobalina · 2026-10-20T05:45:10-0400

Tangdora said:
if you don’t want to use the interface to control your dose. Set a profile and directly specify the direction you want the pumps to run. Then call the profile rather then just calling THEN ON

There is also a WC task option that will set up the commands for you.

The WC task wizard/task is what I have been using to set it up. I'm not sure what you mean by using the interface? Do you mean using the advanced area to write my own programming?

I've only had Apex for about a month and it's been pretty finicky all around, but I can usually find answers when I come on here. I'm a newb for sure and unsure that my programming would be any better lol. I cannot figure out how one day the pump was using the the proper tubing and the next day it reversed itself. I performed the exact same steps to initiate the WC. I will look into you suggestion about setting the profile.