Equipment Review: Aquarium Engineering ACR (Automatic Calcium Reactor)

[Dennis Cartier]

Hey Dennis, need your help with my ACR. Have had it for 2 years and has mostly worked as expected. Then about 2 months back it started getting 1” of “air” and I haven’t been able to get it working consistently since. So a few weeks ago I then swapped to Bill’s newest controller which has a pinch valve for the effluent and for the CO2. No matter what I do, I’m getting a1-2” air pocket and it’s def not air bubbles (confirmed by running sicce feed pump in bucket next to it and had same issue)…it’s excess CO2 building up…to the point of dropping right below the recirculating pump input so it’s basically DOA at that point

Bill said with these new pinch valves on the CO2 line, if the CO2 pressure is up too high it’ll force CO2 past the closed valve, so I turned it down, but then it’s too low and (with the valve box open) I can see effluent flowing through the CO2 line toward the regulator…it seems like it’s impossible to get the CO2 to perfect equilibrium so that it’s high enough to counter the effluent pressure, but low enough to not force through the pinch valve. While trying to get this working today (twice) the reactor ended up blasting the tank with that 1.5” of effluent too, which shot the dKh up.

And worse I removed my feed line check valve temporarily to see if that helped, walked away for 30 min, and in that timeframe I also got a dreaded back feed…even though the tank return pump feeding it never was off. Possible the CO2 pressure forced a backfeed?

Any suggestions?

I just re-read your post. You should never have effluent flowing past the valve box towards the regulator. If you do, then the check valve inside the valve box has failed and is not preventing the effluent from getting to the solenoids and in your case, going past towards your CO2 regulator. The corrosion on the solenoid in my valve box suggests I also had effluent getting to places where it should not be.

Anyone running the factory controller, I suggest you place a quality aftermarket CO2 rated check valve between the ACR CO2 line and the factory controller to protect upstream equipment (factory controller, regulator, etc.).

Dennis

 

[BrianReefer]

I just re-read your post. You should never have effluent flowing past the valve box towards the regulator. If you do, then the check valve inside the valve box has failed and is not preventing the effluent from getting to the solenoids and in your case, going past towards your CO2 regulator. The corrosion on the solenoid in my valve box suggests I also had effluent getting to places where it should not be.

Anyone running the factory controller, I suggest you place a quality aftermarket CO2 rated check valve between the ACR CO2 line and the factory controller to protect upstream equipment (factory controller, regulator, etc.).

Dennis

Dennis, see the pic of my updated controller. There is no longer a check valve on the CO2 line, there’s just a pinch valve now. That’s why if CO2 isn’t high enough, the effluent just flows back to the regulator. I can / will add one now, but even then it seems I need my CO2 pressure in “absolute perfect balance” to only let enough in for use / not expand the CO2 bubble, but enough to fight the effluent back pressure against it, no?

 

[Dennis Cartier]

Extremely helpful, thank you Dennis

A few follow up questions:
1) Why do we need to bypass the input check valve on startup? Is it to allow CO2 back into the feed back during equalization, and if so, isn’t that CO2 going to go back into my tank during those first few minutes?
2) When you say “Now close the effluent drain and then after a minute or two, close the feed check valve bypass”…on the first part, I assume you mean close the diverted drain and open back up the main tank effluent line at that point?
3) Is there any trick to setting the right CO2 pressure on the regulator? In my updated controller the CO2 valve bill uses is the same as the effluent valve, it is a pinch valve too now (see pic), if I set it too high CO2 pushes past the pinch and eventually expands that CO2 bubble causing the issue, if I set it too low effluent backfeeds when the valve opens back into the regulator. I think ultimately this is my biggest problem.

Thx again

Wow, this is quite different from the v2 setup that I had. My thoughts on this design will follow answers to your questions.

1. Yes, sort of. By opening the effluent drain that was added to the effluent line, you prevent the back feed from occurring, and still expose the reactor to the feed pump head pressure. If you don't have the added effluent drain, or forgot to use it, then opening the bypass for the check valve will cause back feed, but your reactor will startup and equalize successfully and avoid the gas build up issue.
2. Yes, exactly. The added effluent drain is just there to provide a place for the effluent displaced by the CO2 entering the reactor to go (other than the tank).
3. Well that depends on the head pressure of your feed pump. The problem is that there is no easy way of telling what the head pressure of your feed pump is. I have my regulator running at 8 PSI currently and have ran it at 10 PSI in the past. In my case, I have an IFM pressure transducer installed on the reactor side and can see the internal pressure of the CO2 gas bubble at all times.

This new design has a number issues that would concern me even more than the v2 design that I had/have. Using a pinch valve for regulating CO2 is going to be fraught with problems. As you have experienced, effluent can be pushed past it if the head pressure of your feed pump is too high. I don't know what the rated max pressure of the pinch valve used is, but I would not be surprised if it is in between 15 - 25 PSI, and in my view not a good solution for regulating CO2. The speed of the pinch valve cycling is going to be way too slow and allow more CO2 than ideal to flow past. If the head pressure of your feed pump exceeds the rated pressure of the pinch valve, then there is no way that you can set your CO2 regulator high enough to allow the CO2 to overcome the head pressure of the feed pump, without it exceeding the rated max pressure of the pinch valve. I expect this is the issue you are running into. On the bright side, no corrosion using the new design.

If you can feed your ACR from a smaller, lower head pressure pump, I would try that. If the issue goes away, then your pump was just too much for the pinch valve's rated pressure. By all means though, place a CO2 check valve after your regulator if you continue to use this controller. Otherwise your CO2 regulator will risk being damaged.

Personally I would not use this new design of controller either and would still recommend a continuous duty peristaltic pump and Clippard valve instead.

Dennis

 

[BrianReefer]

Thanks Dennis, this helps clarify a ton for me. I added the check valve on the CO2 line and am now testing the setup with a sicce pump in a bucket upstairs and an effluent drain line. If I can get this to stabilize I know there’s hope! Then can I transfer the setup to my main return manifold at lower pressure and try it again there.

Just don’t want to tick off my SPS any more than I already did yesterday so going to force myself to take this one slow

Is all I’d need to replace all of this hassle a Kamoer peristaltic pump and the clippard valve basically?

 

[Dennis Cartier]

Thanks Dennis, this helps clarify a ton for me. I added the check valve on the CO2 line and am now testing the setup with a sicce pump in a bucket upstairs and an effluent drain line. If I can get this to stabilize I know there’s hope! Then can I transfer the setup to my main return manifold at lower pressure and try it again there.

Just don’t want to tick off my SPS any more than I already did yesterday so going to force myself to take this one slow

Is all I’d need to replace all of this hassle a Kamoer peristaltic pump and the clippard valve basically?

Yup, that is exactly what you would need. Then you adjust your dKH by the speed of the peristaltic pump and let the Clippard valve handle the CO2. If you install the peristaltic pump on the drain side of the reactor (where the pinch valve was), then you will need a check valve and effluent drain (for start up). If installed on the feed side, in place of the feed pump, then you will only need the effluent drain.

Dennis

 

[BrianReefer]

So, it’s proving to be more challenging that I thought. Did everything as described, the reactor ran for 4-5 hours fine, and then 20 min ago, the CO2 pocket formed again. Very frustrating. I think I have to just keep tuning the Tunze regulator needle valve to find the exact pressure that’s at equilibrium with the input water pressure, if that’s even possible since I’m sure that pressure changes occasionally too…

So frustrating

 

[Dennis Cartier]

So, it’s proving to be more challenging that I thought. Did everything as described, the reactor ran for 4-5 hours fine, and then 20 min ago, the CO2 pocket formed again. Very frustrating. I think I have to just keep tuning the Tunze regulator needle valve to find the exact pressure that’s at equilibrium with the input water pressure, if that’s even possible since I’m sure that pressure changes occasionally too…

So frustrating

Hmm, does your regulator not use a knob for setting the pressure? For the ACR, I would not expect a needle valve to be useful as we are not dealing with bubble counts, we just want CO2 provided at a preset pressure. Does your regulator have an output pressure gauge? If so what pressure are you running at?

Dennis

 

[BrianReefer]

Hmm, does your regulator not use a knob for setting the pressure? For the ACR, I would not expect a needle valve to be useful as we are not dealing with bubble counts, we just want CO2 provided at a preset pressure. Does your regulator have an output pressure gauge? If so what pressure are you running at?

Dennis

Sorry, I meant the needle valve on the regulator, the tunze regulator has a main knob and a needle valve dial for fine tuning. I’m thinking I need to keep working that fine tuning to try to get this thing balanced…?

 

[Dennis Cartier]

Sorry, I meant the needle valve on the regulator, the tunze regulator has a main knob and a needle valve dial for fine tuning. I’m thinking I need to keep working that fine tuning to try to get this thing balanced…?

I went and looked at the Tunze manual for (hopefully) the regulator you have. The needle valve sounds like a flow control mechanism. Like a speed control for pneumatic lines. I am not sure it will be helpful in your situation. You are more concerned with the pressure rather than how fast the CO2 is added. Though the pinch valve that is controlling the CO2 will be fairly slow opening and closing (for a valve), so perhaps slowing the time that the CO2 will take to reach the pressure that the regulator is set to may have some application?

A user with an ACR posted into his build of his switchover to the Clippard valve that I am using. You can see it here (Mattgsa 315 gallon build) to get an idea of what is involved to remove dependency on the factory controller.

Dennis

 

[Dennis Cartier]

So, it’s proving to be more challenging that I thought. Did everything as described, the reactor ran for 4-5 hours fine, and then 20 min ago, the CO2 pocket formed again. Very frustrating. I think I have to just keep tuning the Tunze regulator needle valve to find the exact pressure that’s at equilibrium with the input water pressure, if that’s even possible since I’m sure that pressure changes occasionally too…

So frustrating

If you are still running this in a bucket, try leaving your feed line check valve disabled by opening the bypass (if you added one already) or remove the check valve if you don't have a bypass. Then see if the reactor is able to run for 12 hours without the CO2 expanding past the float valve. This will help to confirm that it is simply a over pressure situation and not pushing past the CO2 pinch valve.

This new controller design may work differently in the presence of a check valve on the feed line.

Also, running in a bucket without fresh, low CO2, water entering through the feed line will not give exactly the same results as when running on your tank as the water in the reactor will not be able to absorb anymore CO2 as it is already saturated. This may impact the results. The same situation occurs in my installation when my Alkatronic shuts my peristaltic pump down when the alkalinity goes over my preset level. When this happens, the cycling of the float valve adding CO2 slows and eventually stops, and remains paused until the peristaltic pump is re-enabled.

Dennis

 

[BrianReefer]

If you are still running this in a bucket, try leaving your feed line check valve disabled by opening the bypass (if you added one already) or remove the check valve if you don't have a bypass. Then see if the reactor is able to run for 12 hours without the CO2 expanding past the float valve. This will help to confirm that it is simply a over pressure situation and not pushing past the CO2 pinch valve.

This new controller design may work differently in the presence of a check valve on the feed line.

Also, running in a bucket without fresh, low CO2, water entering through the feed line will not give exactly the same results as when running on your tank as the water in the reactor will not be able to absorb anymore CO2 as it is already saturated. This may impact the results. The same situation occurs in my installation when my Alkatronic shuts my peristaltic pump down when the alkalinity goes over my preset level. When this happens, the cycling of the float valve adding CO2 slows and eventually stops, and remains paused until the peristaltic pump is re-enabled.

Dennis

Hey Dennis-

This is exactly what I did yesterday, though I ran the input feed line also out of the same bucket using a sicce feed pump. I did this because with the feedline check valve off during a similar test the prior day, effluent backfed into my tank via the feedline (my guess was the CO2 Expansion forced it back up the line) causing a dKh spike of over 1 which I didn’t want to happen again. When I ran the bucket in/out test for 6-7 hours yesterday it was pretty stable, after which I switched it to my tank feedline with effluent to the bucket, then that ran stable for 5-6 hours, then last night the air pocket suddenly formed again. Does that give you any new data point / ideas?

I could also unplug the CO2 line on the output side of the valve and put it under the CO2 monitor I have to see if it spikes?

 

[Dennis Cartier]

Hey Dennis-

This is exactly what I did yesterday, though I ran the input feed line also out of the same bucket using a sicce feed pump. I did this because with the feedline check valve off during a similar test the prior day, effluent backfed into my tank via the feedline (my guess was the CO2 Expansion forced it back up the line) causing a dKh spike of over 1 which I didn’t want to happen again. When I ran the bucket in/out test for 6-7 hours yesterday it was pretty stable, after which I switched it to my tank feedline with effluent to the bucket, then that ran stable for 5-6 hours, then last night the air pocket suddenly formed again. Does that give you any new data point / ideas?

I could also unplug the CO2 line on the output side of the valve and put it under the CO2 monitor I have to see if it spikes?

No I get the whole dKH spike issue. I actually recently caused the same thing on my tank when I forgot to close my check valve bypass after installing some new equipment and then accidently disabled the feed pump while working on a different project.

The Tunze regulator is most likely a single stage. Single stage regs can have issues with maintaining constant stable pressure at the end of a CO2 tank. Is your CO2 full or could it be nearing empty? The Tunze reg you have, does it use bar for the gauges and if so, what do you have the output set to? Ditto if it uses PSI.

Dennis

 

[BrianReefer]

No I get the whole dKH spike issue. I actually recently caused the same thing on my tank when I forgot to close my check valve bypass after installing some new equipment and then accidently disabled the feed pump while working on a different project.

The Tunze regulator is most likely a single stage. Single stage regs can have issues with maintaining constant stable pressure at the end of a CO2 tank. Is your CO2 full or could it be nearing empty? The Tunze reg you have, does it use bar for the gauges and if so, what do you have the output set to? Ditto if it uses PSI.

Dennis

I got the tank filled about a month ago when these issues started thinking that could be the cause. Here’s my current pressure, just fired it up again 10 min ago after having it off overnight…purged the air to get the water line back and have CO2 going in now. Trying to keep pressure as low as possible while still getting the CO2 sounds from the reactor to find this ‘balance’

Please keep any thoughts or suggestions coming. I’m kind of just doing the same thing hoping for better results with more active ‘fine tuning’ of regulator!

 

[Dennis Cartier]

Ah, OK, so I am looking at the right model, good. That setting translates to about 9.4 PSI, which is a good safe pressure. I would just open up the needle valve and not worry about tuning it. Because the ACR uses a float switch, the needle valve is kind of redundant.

The principle behind the design of the ACR, if given appropriate pressure, the CO2 setting should be a non-issue. I suspect the issue lies elsewhere.

Dennis

 

[Dennis Cartier]

I just re-read your original post on the issue. This problem started before you swapped controllers. Any chance the feed pump is picking up a large volume of bubbles?

Did you send the old controller back to Bill or do have it still? I am wondering if you have a spare float switch cable on hand with the connector for the ACR.

Dennis

 

[BrianReefer]

I just re-read your original post on the issue. This problem started before you swapped controllers. Any chance the feed pump is picking up a large volume of bubbles?

Did you send the old controller back to Bill or do have it still? I am wondering if you have a spare float switch cable on hand with the connector for the ACR.

Dennis

No chance of bubbles, both the sicce test pump and my main return pump were completely submerged and no air getting in, and I had the reactor running great for months from my main return pump with no air issues.

Sent the old one back unfortunately! What would we do with the spare cable?

 

[BrianReefer]

No chance of bubbles, both the sicce test pump and my main return pump were completely submerged and no air getting in, and I had the reactor running great for months from my main return pump with no air issues.

Sent the old one back unfortunately! What would we do with the spare cable?

But I do have this extra cable he sent with one of the replacements at some point…if this helps us run any tests?

 

[BrianReefer]

Ah, OK, so I am looking at the right model, good. That setting translates to about 9.4 PSI, which is a good safe pressure. I would just open up the needle valve and not worry about tuning it. Because the ACR uses a float switch, the needle valve is kind of redundant.

The principle behind the design of the ACR, if given appropriate pressure, the CO2 setting should be a non-issue. I suspect the issue lies elsewhere.

Dennis

Actually on this, when I talked to Bill 2 weeks ago, he said if the CO2 pressure is too high, it CAN force air past the new pinch valve (vs the old solenoid design where CO2 pressure didn’t matter) so that leads me to believe it is a situation where I need to manually find “perfect balance” where CO2 goes in, doesn’t push past valve, but has just enough pressure to overcome the effluent back flow down that CO2 line…?

He told me to set it to a very low pressure…”just where you see bubbles” when you put the CO2 line in water…which I get well under this 9.4 PSI… but that low pressure doesn’t overcome the effluent back flow or get bubbles going in the reactor so I had to move it up to that 9.4

 

[BrianReefer]

To anyone following along, thanks to Dennis' help and troubleshooting I figured out the issue and have it working again.

My issue: Saltwater got into the float valve over time (water got into the seam between the float valve nut at the lid area it screws into). From there, salt accumulated, and oxidized the wires of the float valve. And because of that, the float switch was no longer consistently firing to trigger the new controller's CO2 pinch valve, leaving it always on, causing CO2 to constantly stream and accumulate in the reactor, until the water level dropped 2". At first I thought the wire oxidization would only go partway up the float valve wire, but when cut the wire right before the connector to the controller, I saw one of the wires (that was copper) was black. Hacked a float valve replacement with my own float valve and it's now working again.

So the PSA here is...keep an eye on that float valve. There is no gasket between the valve nut and lid top and it seems eventually water will get in and do what happened to mine.

 

[Dennis Cartier]

When I saw the oxidized copper, it shocked me that salt managed to get in there. Your float switch appears to use a carrier that screws into the lid of the ACR and has the float switch screwed into that. My reactor does not use that style and has a flat pressure fit style plug/cap to seal the float switch recess. I am not sure if yours is a newer or older design. The same caution applies though for all variations. If that float switch is not water tight, then contamination is a real possibility and as Brian mentioned, should be monitored.

The float switch used in the ACR is an off the shelf Madison float switch and can be ordered from various sources (including Amazon).

Dennis