Kessil

Pros/cons of automatic water changes

BleepBloopMunchMunch

Supporting Member
I have been thinking about this since I will be away from my tank for a few stretches of time in the coming months. I usually do a 5 gallon water change once a week on my 90 gallon system and thats easy enough to have someone else do when I am gone but I thought if there are a lot of other advantages to it, it may be worth it to not only save someone else from doing it when I am gone, but also so I don't have to do it myself.
The main cons I can think of is storing a lot of saltwater somewhere accessible, cost of extra equipment and saltwater and my main fear having just another point of failure, anything that has the potential to drain or fill my entire tank scares me in case anything about it goes wrong. I also do like doing water changed to siphon out things like nuissance algae and gunk
 
If you're considering it, I love my AWC. Runs 4x a day, every 6 hours. Small percentage each change, over-time, adds up. If I want to increase/decrease the amount of change, the amount changed is easily tuned for whatever reason.

Cons: a few rakes were stepped on initially. Back-flow siphoning and some not-smart mistakes related to basic physics. And there's the cost. But I won't have a tank without it, at least until my mind changes.

Pros: clockwork-like water changes. Less spillage. Less work doing water changes, more on other stuff. I still siphon out detritus and vacuum sand. I just siphon into a filter sock.
 
A key problem to deal with : Forgetting to refill the new salt water tank.
Procrastination, vacation, general forgetfulness.
It will happen.

You really should have some sort of float switch that disables exchange when tank is empty.
Otherwise it will slowly suck salt water out of display tank, and replace it with air.
Which assuming you have an auto-top-off, means salinity will slowly drop.

That warning aside .... I really like my AWC system.
A very simple way to keep parameters stable.
Eliminates one of the big hassles.
But not something I would call a "must have"
 
Unless you're able to store enough water for multiple changes I don't think it's worth it. I only had the capacity for three 10% changes so the effort/resources wasn't worth it anymore. The trade-off was that I could utilize my DOS for dosing again, no more loud dos spinning (my setup was under the kitchen cabinets), and I can take the time to suck out detritus. Good 'ol trash bins on dollys for me again.
 
Dosing pumps also degrade over time. I had a AWC back when I had my ELOS tank up. It was great for the first month or so, but then I had to keep testing and adjusting based on the inconsistencies. Given, I was using a pretty lousy dosing pump and nothing fancy like the Apex DOS.

I wanted to get the Genesis AWC system:

But then they were going out of business, so good thing I didn't go down that route.

I've gone out of town for longer periods and just didn't do any water changes (skipped 3 weeks). Tank was just fine.
 
Dosing pumps also degrade over time. I had a AWC back when I had my ELOS tank up. It was great for the first month or so, but then I had to keep testing and adjusting based on the inconsistencies. Given, I was using a pretty lousy dosing pump and nothing fancy like the Apex DOS.

I wanted to get the Genesis AWC system:

But then they were going out of business, so good thing I didn't go down that route.

I've gone out of town for longer periods and just didn't do any water changes (skipped 3 weeks). Tank was just fine.
I got the genesis system just a bit before they went out of business. I'm still glad I got it.
 
I think it comes down to the system size. When doing a water change, ask yourself what are you trying to fix and will the water change solve or dilute the problem. On my system, I decided it was too large to rely on water changes, so I try to solve the reason behind the water change. In a smaller system, say <50 gallons, I could make enough salt water in one sitting to have enough clean water to solve the problem I am trying to fix. I also think that anything that gets you more engaged with the tank will result in a healthier tank as you notice the small changes more often.
 
I think it comes down to the system size. When doing a water change, ask yourself what are you trying to fix and will the water change solve or dilute the problem. On my system, I decided it was too large to rely on water changes, so I try to solve the reason behind the water change. In a smaller system, say <50 gallons, I could make enough salt water in one sitting to have enough clean water to solve the problem I am trying to fix. I also think that anything that gets you more engaged with the tank will result in a healthier tank as you notice the small changes more often.
More engaged is key, but also make it fun, otherwise you'll burn out.

My tank is small enough where water changes are pretty easy. But I'm thinking of making it even easier with a water mixing station, and a pump rather than lugging a couple of buckets around.
 
iMHO and experience...
Make the water changes large enough to matter
You want to reduce pollutants and replenish the depleted ions from biological processes
On a 90 gallon system, I would change 20-25 gallons
Disclosure
I use NSW and I test nothing
I care for some of the oldest fish and systems in the club
I am totally manual
Automation requires reliable sensors and maintenance and calibration
 
Thanks everybody for your experience and advice, as always appreciate the wide range of knowledge in the club. A lot of what people say confirms what I had been thinking the AWC too. I probably won’t do any changes before I can be home to observe for a long amount of time, but what systems have people been using? I know there’s things like the DOS but also stand alone specific AWC units
 
I started looking at this one: kamoer xs2, not sure if it's available in the US yet, but I've always wanted a AWC.

link to a youtube video:
 
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