Neptune DOS Manual Water Change (REMOVE, then ADD)

[SPS2020]

Hello All,

Is there a way to perform a manual water change with the DOS such that it will REMOVE the specified amount of water, then ADD the new water? My thought is that this is more efficient at removing the "bad" water before adding in the "good" water. I've done quite a few searches, but haven't found anything regarding this method.

Are there reasons why I would not want to do it this way? I'm performing a 10 gallon change on my 100 gallon tank with around 15-20 gallons in the Trigger sump. The only caveat I could think of is if the water level became too low and the return pump sucked air. That could be circumvented by decreasing the return volume while the change is taking place over eight hours (I have it programmed for a shorter period).

Thanks for your thoughts!

 

[OSUASCReefer]

I believe the two issues could be 1) having the pump pull air or 2) the return part of the sump kicking your ATO on if it senses a lower level then gradually alters your salinity. I use the DOS for my auto water changes and love it. I have it pulling water from the farthest point I could find from the return pump and have it adding water close to the pump. I have had no issues with this and the salinity and water quality has stayed constant. I do 2 gallons a day, so 14 gallons a week, and 56 gallons a month on a 165 gallon system. Hope this helps!

 

[SuncrestReef]

Three reasons why it's better to just do the add/remove at the exact same time:

1. The water level will not change except for normal evaporation, so there's no need to disable the ATO for the duration of the water change schedule.

2. It's faster. Remove then Add will take twice as long compared to doing it simultaneously. The DOS can only move 1.3 gallons per hour, so a 10 gallon change takes about 7.5 hours. If you remove then add, that stretches it out to 15 hours.

3. The loss of "good" water is trivial. Read this article that shows how little difference in nutrient export occurs:

http://reefkeeping.com/issues/2005-10/rhf/index.php

Scroll down to the last paragraph before the conclusion:

"A continuous water change of 30% exactly matches one batch 26% water change. As with very small batch water changes, these have the advantage of neither stressing the organisms (assuming the change is done reasonably slowly), nor altering the water level in the aquarium. "

 

[SPS2020]

Thanks for the responses! I started doing the math after posting and realized that it would take twice the time to achieve the desired water change...deal breaker.

Great article!

 

[Tdoan]

Hello All,

Is there a way to perform a manual water change with the DOS such that it will REMOVE the specified amount of water, then ADD the new water? My thought is that this is more efficient at removing the "bad" water before adding in the "good" water. I've done quite a few searches, but haven't found anything regarding this method.

Are there reasons why I would not want to do it this way? I'm performing a 10 gallon change on my 100 gallon tank with around 15-20 gallons in the Trigger sump. The only caveat I could think of is if the water level became too low and the return pump sucked air. That could be circumvented by decreasing the return volume while the change is taking place over eight hours (I have it programmed for a shorter period).

Thanks for your thoughts!

Her is the way I do water changes.
Thread 'DYI Auto Water Change' https://www.reef2reef.com/threads/dyi-auto-water-change.894565/

 

[SPS2020]

Her is the way I do water changes.
Thread 'DYI Auto Water Change' https://www.reef2reef.com/threads/dyi-auto-water-change.894565/

Nice! Thanks for that post.