Auto water changes with sump overflow drain?

[vetpath1]

I'm in the early stages of my 195 g in-wall mixed reef tank build.  I'm very interested in automating my water changes, both for stability and convenience.  Originally I thought I might purchase the AutoAqua system for AWC and ATO, but that product has been discontinued.  I may instead have to go the Apex Dos route (I already own an Apex, but I'd have to purchase the Dos).  But I have another idea for accomplishing AWC that I haven't seen posted anywhere yet, so I don't know if it's workable.  I was wondering if I could drill into the return section of my sump, insert a bulkhead with an overflow drain, and then simply pump a gallon of new salt water into the display tank several times per day using my Apex or some other timer and a small pump?  The water level in the return section would therefore never exceed the level of the drain, so that would essentially eliminate the possibility of flooding (unless the outflows from the display tank or sump became obstructed). I could configure the system so that the ATO (separate device) would be switched off during those auto changes.  To me that approach seems simpler, less expensive, and less prone to failure than the Apex/Dos method.  Seems too easy, am I missing something?  Thanks in advance to all who respond.

[cpeguero]

I thought about doing this in my build. The issue I see is events out of the ordinary causing water overflow. These could include:

-return pump shutting off
-if you’re using a roller mat or filter sock, changes in water level when fleece is advanced or sock Is changed
-ATO fails on. You don’t having an ever rising water level, so you don’t have a float switch to shut it off

I ended up using the GHL maxi doser for mine. I do use that sort of AWC for my QT. I use the “waste” water from the display AWC in an overflow style like you’re describing. Thing is, the QT just had a power filter, powerhead, and heater. Nothing else to mess with the water level.

You can likely solve the problems I listed above with other automation/failsafes, but for me, I feel it defeats the purpose of an otherwise simple setup.


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[vetpath1]

Thanks for the fast response!  I appreciate the feedback. 

 

Yeah, I was also planning on having the display AWC waste feed the QT system and do a flow-through there too.

 

Do you control your GHL doser with its native system, or do you use a controller?  I understand that particular doser model has been discontinued.

 

So with your doser system, don't you still have the potential for similar problems with return pump or ATO pump fails, or filter material clogs?  Do you have other safeguards for those?

 

Sorry to bug you with more questions (no good deed goes unpunished!)

[cpeguero]

Glad to share info!

I initially bought the stand alone version, but have since bought a profilux and use that for control. Yes, they have a new version in the works. This one works great though. Not sure if the dozer heads will be interchangeable, but hoping they will be. Otherwise, I can use DOS heads.

I use a Reefbreeders Exo-ATO. rock solid. No issues. Have one on another tank as well. It has built in logic to shut it off if it’s on too often or too long.

I also have float switches set to shut off the ATO through the profilux if the water level in the sump gets too high or too low and will notify me.

No real issue with fluctuating water level. I have two Klir DI-7’s. Return water level does fluctuate, but not enough to prevent ATO from working.

I also rely on the calibration of the Maxi doses to change the same amount of water. I don’t use float switches. I do have to keep an eye on salinity to ensure they aren’t too far off. Only had the Austen up for about six months. No issues with salinity so far.

If the return pump shuts off, AWC won’t happen. Honestly, the only time that happens is if there’s a power outage.


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[vetpath1]

Thanks for the additional information (and sorry for not getting back to this for awhile).  I'll try to let you know what I end up deciding in case you're interested.

 

BTW, I just (mostly) finished my mixing station.  I will be adding a drip tray below the upper container, and the RODI unit is purchased but not plumbed in yet.  It's all pretty basic, with gravity feed from the freshwater to the salt.  But it takes up relatively little floor space, it will be easy to add salt because the bottom container is on wheels and connected by a flexible hose, and since it will be only several feet away from the display tank (on order), I can easily use a drop-in pump and another hose to fill the tank until I get an AWC system up and running.  I also don't have to maintain an external pump.  The front spigot is for filling the occasional bucket with RODI water if needed.  As is probably obvious, the clear tube attached to the upper container indicates the water level, which I copied from another system seen online.

 

Happy reefing!