DOS as AWC Pump

ca1ore

Grizzled & Cynical
Am considering the Apex DOS as a automated water change pump. Anyone been doing this for a while (recognizing that it's not that long in the market)? I'm thinking about using one head to add NSW and the other to remove OSW. Do they stay in synch? Do differential levels affect dosing rate? Do you need the same length of tubing on both dosing heads? Etc, etc.
 
I've been using a DOS for my AWC for more than a year now and it's been working great. Each head can be calibrated separately, so if you calibrate with the final tubing in place you shouldn't need to worry about having to use the same length of tubing or anything. I have it set to add nsw in my return pump chamber and remove osw from the chamber that my tank drains into, so the pumps can run simultaneously without pulling out water that was just added. I change about 3G a day on my 220G tank
 
Awesome, that is precisely what I was thinking about doing. Levels in the NSW tub don't mess with your calibrations?
 
I've been using mine for a while now. Maybe 2-3 years. I run new>DT>QT>waste with air gaps to prevent any backflow. My salinity stays where it should and the DOS gives me pretty great flexibility in change rate. I've done large changes of about 90,000ml/day to bring down my magnesium after a bryopsis fight and typically change a gallon per day..
 
I've been using a DOS for my AWC for more than a year now and it's been working great. Each head can be calibrated separately, so if you calibrate with the final tubing in place you shouldn't need to worry about having to use the same length of tubing or anything. I have it set to add nsw in my return pump chamber and remove osw from the chamber that my tank drains into, so the pumps can run simultaneously without pulling out water that was just added. I change about 3G a day on my 220G tank

This is how I have mine set up. Mine starts at 12noon to 8pm for a gallon change a day. I don't use a heater in the NSW container because the NSW is added at a very slow rate and won't affect the temp in the tank. Also using this slow of a rate my ATO does not kick in and I don't have to use other code to turn it off when the DOS pumps are on.
 
Been running mine for about a year now and recalibrate it every 4-6 months just to be safe. I think it has been pretty much spot on with the one head drifting a ml.

tank and sink are a solid 25 feet away give or take.
 
I am planning on using the dos for constant water changes.My barrels,100g cylinders will be about 80 ft away in the garage,I am thinking of running 3/8" line for the major length,and then reduce to 1/4" to the dos which will be in the sump cabinet.The difference in height from where the pump will be mounted to the storage tanks will be about 2-3ft (purely a guess at this point) do any of you using this system foresee any back flow issues,if so would a check valve be advisable.
 
How have your hoses held up? I have about 30 feet of the hard RO tubing running from the basement connected into a foot or so of the clear tubing. I was just wondering how the salt water will effect the tubing over time.
 
I have not had any issues with my hoses. I do run vinegar through them once every 6 months to help with any potential build up but I have yet to notice anything.
 
Do you use two DOS's for this? I've been considering trying to do something like this, but I couldn't come up with a good option that didn't need three heads.

Just put a stand pipe in the QT. that's what I'm planning to do.
 
Just put a stand pipe in the QT. that's what I'm planning to do.

For this to work you would need to have an ATO and have it configured to keep the water level *exactly* at the top of the standpipe.

If it's configured slightly too high then the ATO will keep adding fresh water and send salt water down the standpipe, slowly lowering the salinity in the tank.

If it's configured slightly too low then you will be adding slightly more saltwater than you're removing as the water level rises to the standpipe each time the AWC runs and the salinity will slowly increase.

I don't think this will really work in practice.
 
My plan was to use the DoS just to fill the QT. Once filled, I'd direct the DoS tube down the stand pipe. AWS isn't really necessary for the QT, and is undesirable when running meds.
 
I have seen numerous reviews on the Stenner and they all said it was a good unit. I would still do a calibration to double check the heads match. It wouldn't take much and it might let you sleep better at night.
 
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