Programming DOS to remove water from sump apart from AWC cycle.

[DanP-SD]

I’m looking to add a bit of programming to my DOS routine and am hoping someone has figure out how to do this. My DOS currently does AWC only. I want to install a momentary button and create programming so that, when I press the button, the DOS halts the AWC (if it’s in process), drains a set amount of water from the sump to the drain, and then resumes the AWC.

For background, the reason I want this is that, from time to time, my skimmer pulls out enough water that the ATO reduces salinity in the tank. When I see salinity drop, I will add saltwater. That raises the sump level which, left unchecked, would cause the skimmer to drain more saltwater. So I drain some saltwater from the sump to restore the level.

Currently, the way I do so is manually with a bucket. But my DOS “remove” head is plumbed to do this already so I’d like to set up a program for it.

I think I can do it by time (press the momentary button and the remove head activates for a set time, which I calibrate to drop the sump level say 1/2”). That would require I press it multiple times if I need to remove more than 1/2”. Or I can program it to remove water until the sump level drops to an optical sensor. This would be my preferred approach because I press it once and it’s done.

Has anyone tried something like this? If so, can you post your code? Any thoughts on how to program this but not have the water removed through this routine count toward the AWC program? If the APEX sees the water removed this way as part of the AWC remove, I believe it will reduce how much water it removes the rest of the day to keep the remove and add volumes balanced. That would defeat the purpose.

It occurs to me I may be better off just adding a separate pump to drain the excess water but I’d like to further explore the feasibility of using the DOS since it’s already there and avoids more gear in the sump.

 

[cdemoss01]

This is a complicated question, this answer is experimental so try it at your own risk. Also try contacting Apex, they are an extremely smart company.

• Momentary push button (wired into a Breakout Box on your Apex).
• Optical sensor (e.g., Neptune LD-2 or similar) installed in the sump at your desired low water level.

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Apex Programming Concept​

Virtual Outlet (e.g., DrainingSW)​

Use this to represent the manual saltwater drain routine.


Fallback OFF
Set OFF
If Switch1 CLOSED Then ON // This is your momentary button (e.g., `Sw1`)
Defer 001:00 Then ON // Optional: Prevent multiple rapid presses
If DrainingSW = ON Then OFF // Prevent indefinite run

DOS Head Control Outlet (e.g., DOS_Drain)​

Control the actual DOS head for draining.


Fallback OFF
Set OFF
If Output DrainingSW = ON Then ON
If Output AWC_Remove = ON Then ON // Normal AWC schedule

Optional: Stop Draining When Sensor is Hit​

If you're using a float or optical sensor:


apex
CopyEdit
If Sensor1 OPEN Then OFF // Sensor1 is your low water level mark

Prevent DOS Drain from Affecting AWC​

You’re right: DOS balances add/remove volumes based on historical use. To prevent manual drains from affecting this:

1. Use a different DOS head than the one used for AWC (ideal but may not be feasible).
2. Logically separate the drain routine so the AWC program only tracks its own dose history. In Fusion, set up separate dose profiles and do not share profiles between the AWC remove and manual drain routines.
3. Manual Drain Logging: Consider turning off dose tracking for the manual drain dose profile or record its usage elsewhere if necessary.

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Optional: Multi-Press Handling​

If you stick with a fixed volume per button press, you could implement a short lockout (like a 1-minute timer) or count presses with a virtual counter if you want to drain more without repeating the whole drain cycle.

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Alternate Path: Separate Drain Pump​

If you find this too limiting, a small DC utility pump controlled by Apex via EB832 or a relay could be a more responsive solution and won't interfere with your AWC tracking.

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Would you like help writing exact Apex code for this setup, or details on wiring the momentary switch and optical sensor to the breakout box?

 

[DanP-SD]

Thank you. This is very helpful insight. I don’t need help formulating the specific code. I was looking for either someone who has done exactly what I’m trying to do or the kind of insight and thought you’ve provided.

I’m leaning toward using a separate pump. As I dig into this, I think the big challenge with the DOS is going to be preventing it from logging the drain function against the daily total on the remove side of the AWC program. My AWC routine is working well as is and it seems that the cost of a small DC pump is a small price to pay to keep these functions distinct.

 

[cdemoss01]

Thank you. This is very helpful insight. I don’t need help formulating the specific code. I was looking for either someone who has done exactly what I’m trying to do or the kind of insight and thought you’ve provided.

I’m leaning toward using a separate pump. As I dig into this, I think the big challenge with the DOS is going to be preventing it from logging the drain function against the daily total on the remove side of the AWC program. My AWC routine is working well as is and it seems that the cost of a small DC pump is a small price to pay to keep these functions distinct.

Programming is tough, Apex could help you further.

 

[nickng]

Hi, did you manage to figure this out? I think I have my apex and dos WC set up close to what you are looking for.
My DOS WC does a WC between midnight and 4am. It 1st removes approx 1.5 gallons from midnight to 2am and then adds back NSW between 2 to 4am.
I have 3 separate momentary push buttons set to do the following when given a single push, add 500ml RODI, remove 500ml water from sump, add 500ml NSW. Each button activates for 15 minutes to do the tasks above.
Also I configured the feed buttons B,C,D on the Apex phone app to do the same tasks as the momentary push buttons. The reason for adding this function on the feed buttons is because (1) app has a count down clock so that I know when the task has been completed (2) able to issue the commands from anywhere as long as there is WIFI connection.
Also I have an LLS and optical sensor to tell me how much the water level changed in the sump.

 

[nickng]

If interested, I can cut and paste my set up on this thread