I finally got around to servicing and maintaining my ACR. I had been telling myself that I wanted to see what would happen, when would the depleted media become a pressing need to be replaced, but in reality I was just being lazy. The powder that was being passed out of the effluent line had already become a problem for downstream equipment. My powered secondary chamber, a Geo 618, had clogged and started pushing effluent out past the seals, necessitating it's removal, and just using the effluent from the ACR directly.
Leading up to this, my dKH, had been slowly drifting down. So I had a pretty good idea that the effluent had weakened, and was no longer able to provide enough supplementation without boosting flow rates. I had already boosted the effluent base flow rate from 8 ml/min to 10 ml/min.
It all kind of came to a head when the Milwaukee pH controller I was using as a fail safe backup that would shut my effluent pump down if the measured dKH as passed out of my Alkatronic on it's BNC port ever exceed 12 dKH, had a failure of it's switched relay port and shut the effluent pump down even though the dKH was not above the target. I caught the issue after a couple of days, but the dKH had already dropped to 7.05 by that point.
You can see the dKH slowly dropping and then suddenly getting switched off around August 5th. When I noticed the issue and removed the effluent pump from being powered through the Milwaukee, the dKH starts slowly climbing until it settles in at 8.7 or so. I removed and cleaned at maintained the ACR and Geo on the 23rd, prompting the rapid increase in dKH. I had my target dKH set to 10.0, so it leveled off after it reached the target.
Here is a 7 day view of the current dKH plot. It is still in the process of re-balancing the effluent flow to accommodate the 10 ml/min base effluent rate and the target of 10.0 dKH. It will get smoother as the balancer function accumulates the error adjustment over time.
When I finally pulled the trigger and took the ACR offline to be maintained, this is all that was left of the media. About 2" of what can only be described as 'sludge' in the bottom of the media chamber.
This is what the underside of lid looked like up on opening the unit. This must have come from the sludge in the media chamber, though since this is the first servicing, perhaps the residue is expected. Not sure.
Once I emptied the media chamber, I found that there was still solid Reborn media mixed in with the sludge. The Reborn media looked normal, but was easy to crush in my fingers. It seemed like it had been dissolved from the inside out and was kind of hollow.
I am guessing the powered sludge came from too much of the Reborn media reaching this debilitated state. The media chamber was about 40% full when I noticed the appearance of the powder in the ACR.
I rinsed all the leftover media intending to re-use it, but decided to instead just start with all new media in the ACR and Geo. I filled the ACR with Reborn and used Arm, Reef Reactor, and some Remag in the Geo.
On the bright side, the PVC walls of the media chamber were fogged up over the past few months. I was wondering if it was being caused by the CO2 or the low pH, but after cleaning, the media chamber is again back to translucent, so it must have just been the powder/sludge in the water being deposited on the walls.
I am still really pleased with how the ACR performs.
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