New CaRx - Huge hit time system ph - Help?

[Dennis Cartier]

Ahhh yes. I remember that video. I'll have to watch again, but I recall the 2 points you reminded: 1) 2nd chamber didn't have the return on investment effort from a pH perspective but 2) they did pass it through more media creating that stronger effluent.

I'm now on year 2 of my CaRX and have never tested the effluent. It was "tuned" in my opinion because it was providing a steady Alk. Now on the pH journey, it may not be as tuned as I thought b/c it was negatively impacting the pH for the tank. I finally tested the effluent * and it reads 10.2 dkH. CaRX pH is 6.8x That's much less than the 25 dKh starting point in various tuning docs I read. That tells me I need to double the strength and in doing so will also create a lower pH solution.

Following @Dennis Cartier lead, I will further reduce the 20ml/min down to 10ml/min will increase contact time, bring down CaRX pH and effectively make a stronger effluent.


* Can someone help confirm that I tested this correctly with Hanna. 1) Took 5ml of effluent + 5 ml rodi. 2) added the regular reagent amount if 3) Hanna gave me a 5.1dkh. 4) I double that 5.1 so my effluent dkH is 10.2.

That is the correct method of testing your effluent when it exceeds the range of your tester.

Your plan to increase the effluent strength and to decrease the flow sounds fine. If you can flow your effluent through a secondary chamber, it will give you the best chance of a better pH outcome.

 

[ScottB]

This is something that I have been pondering lately. How to get the least amount of pH drop while using a CaRx. Which correlates nicely to your situation.

What I believe is that you need to shoot for the strongest effulent possible, so you can dose as little as possible to your tank.

I will use my setup as an example of this concept. I run an AE ACR in saturation mode, pressurized to 5 psi. The pH inside my reactor is high to mid 5's.

My effulent flows out of the ACR to a powered second stage, a Geo 618 with no CO2 hooked up. Then it flows through a 2" inline cannister filled with ReMag. It finishes off the journey to the sump, passing through an aeration tower that has room air bubbled through it for 90 seconds every 15 minutes.

The pH inside the Geo is 6.10 (+/- 0.03). When it exits the aeration tower it is 6.8 - 7.2 (depending on time of day, higher at night).

My effulent tests at a steady 90 dKH. My baseline flow rate is 8 ml/min. I slow my reactor at night and boost it during peak light hours.

My tank pH over the past 24 hours (tested every 6 hours) was 8.31, 8.27, 8.37, 8.42.

I was dosing kalk, but took it offline to make my tank more tank sitter friendly (it needed to be mixed every 4 days).

I have a lot of systems in place to combat low pH. All the CaRx ones already mentioned, plus outside air to my skimmer, a skimmer pump inside my fuge barrel, an HRV system, etc.

With all that being said, my belief is that to limit the potential pH drop you can get from a CaRx is to limit the amount of effulent required to as little as possible by making it as potent as possible.

When BRS did their video testing if a secondary chamber raises pH, they found that it did not raise the pH to any degree, but greatly strengthened the effulent. So they concluded no, it doesn't raise the pH.

I think they missed the forest for the trees, because having effulent that is 50% stronger (what their test showed), would allow you to dose much less effulent, and get much less drag on your pH as a result. So even in their test, a higher tank pH would result, though they failed to point that out.

So long story short, flow your effulent over as much media as possible, preferably in a powered active stage, to get every last bit of dKh out of the CO2 used. That should give you the highest tank pH while using a CaRx.

I really like the way you think Dennis. When I was running the ACR, it was producing a very potent solution similar to yours and I managed pH okay.

 

[Dennis Cartier]

I really like the way you think Dennis. When I was running the ACR, it was producing a very potent solution similar to yours and I managed pH okay.

Oh hey Scott. It's too bad your ACR is no longer running. The new v4 controller design makes it easy to get super strong effluent just by adjusting the pressure. I get a steady 90 dKH running my ACR at 5 psi.

 

[Crustaceon]

I used to use a strong effluent plus saturated kalk dosing via ato to help with the ph issue.

 

[ScottB]

Oh hey Scott. It's too bad your ACR is no longer running. The new v4 controller design makes it easy to get super strong effluent just by adjusting the pressure. I get a steady 90 dKH running my ACR at 5 psi.

Yeah my fault messing with the regulator and over-pressurized. Back now to just over 1/2 liter ESV and 4 liters kalkwasser per cycle. It is fine. I just make sure everything is full before I leave for vacation.

 

[Saltyanimals]

Oh hey Scott. It's too bad your ACR is no longer running. The new v4 controller design makes it easy to get super strong effluent just by adjusting the pressure. I get a steady 90 dKH running my ACR at 5 psi.

woah. 90 dKH effluent? Here I am trying to get to 25 and trying to double it from there. I thought i may turn the media into mush if I gave it too much CO2 so there is a point of diminishing returns. Is that only possible with a pressurized system?

 

[Dennis Cartier]

woah. 90 dKH effluent? Here I am trying to get to 25 and trying to double it from there. I thought i may turn the media into mush if I gave it too much CO2 so there is a point of diminishing returns. Is that only possible with a pressurized system?

This is going to take some explanation. ;)

The reactor I run, an ACR from the now defunct Aquarium Engineering, is a saturation style reactor, where a surplus of CO2 is fed into the CaRx, and CO2 is dissolved until the water column (inside the reactor) reaches saturation and no more CO2 will dissolve. As the CO2 level within the water column drops from melting the media, more CO2 dissolves from the on hand surplus, bring the water column back to saturation.

These type of reactors, are considered 'automatic' as you don't have to tune them, you simply inject CO2 when requested from the CaRx controller, and you control the flow rate through the reactor to set the supplementation rate.

Typically they use a mechanical float valve to control the CO2 pocket size inside the CaRx. This is how the Dastaco and Deltec CaRx's work, as well as my ACR.

Unfortunately, in the case of the ACR, the factory controllers had issues and would fail after several months. In order to get mine and others ACR's working again, I designed a replacement, DIY controller for the ACR community, the latest version of which incorporates a pressure controller. The addition of the pressure controller allows the user to set a high and low pressure target for the CO2 pocket, and control the CO2 saturation level in the water column.

Running a saturation style reactor this way is a bit of a novel approach, unlike the Dastaco and Deltec's which operate at (basically) atmospheric. How effective this approach is, is what my research thread (mentioned earlier) is intended to explore.

As far as turning the media to mush, I run OG Reborn in my ACR, at a very low pH. I don't have a pH probe inside the CaRx, so I can only speculate the pH is somewhere between 5.2 - 5.9, and my media is just as solid and intact as ever. I suspect the view that operating a CaRx at too low of a pH will turn your media to mush is incorrect, and the water flow pattern inside the reactor is what determines if your media is in danger of breaking down.

In the case of my ACR, it is an up-flow style, with a venturi valve that re-circulates CO2 into the water flow. The other saturation style reactors (Dastaco, Deltec) use plastic filter floss as a trickle filter inside the CO2 pocket to provide a large surface area for the CO2 to dissolve, whereas the ACR uses the surface area of the rising CO2 bubbles to provide the surface area.

Here is a short video showing the bubbles inside an ACR. As you can see, lots of bubbles! :D
https://youtube.com/shorts/K6V7r9J-7NQ
I expect that your CaRx is the normal type using a bubble counter and pH probe, etc. So getting an effluent in the 25 - 30 dKH range from it should be achievable. Then flowing the effluent through a secondary chamber to wring out even more dKH, should put you in the range of 37 - 45 dKH. If we assume an average of 40 dKH, then your flow rate drops from the 20 ml/min you are using now to 5 ml/min, which should help to alleviate the drag on pH you are seeing now.

 

[Saltyanimals]

Very interesting. So you have a magical CaRX. =) That makes alot of sense that you're able to go that high of the potency. For the rest of us regular mortals, looks like that mid 30s and 40s is it. I may try and get a 2nd chamber in at some point. I already have the CaOH experiment going on to see if I can get it to take over as the primary alk provider and throttle back the CaRX because of the pH concerns. The CaOH supplemental has already provided about 0.1 pH unit bump. Experimenting to see I can squeeze more pH out of it while reducing the CaRX pH. Will let that play out for a bit more and see what that does to my pH during the switch. Thank you for the explanation.

 

[Saltyanimals]

I’ve managed to bring my carx dosing down to 10ml/min with a effluent in the upper 30s. So far it’s able to maintain alk along with the CaOH dosing for the pH (instead of Kalk). Tank pH is as high as I’ve seen in my tank in a long time in the 7.9 low to 8.15 high. So far so good but made me rethink the Calcium part.
Carx provides both the alk and calcium. Are we still getting a proportionally balanced calcium with such a small amount of strong alk effluent?

@Dennis Cartier do you find yourself supplementing calcium separately or is your carx still able to maintain it at your 5ml/min dose?

 

[Dennis Cartier]

I’ve managed to bring my carx dosing down to 10ml/min with a effluent in the upper 30s. So far it’s able to maintain alk along with the CaOH dosing for the pH (instead of Kalk). Tank pH is as high as I’ve seen in my tank in a long time in the 7.9 low to 8.15 high. So far so good but made me rethink the Calcium part.
Carx provides both the alk and calcium. Are we still getting a proportionally balanced calcium with such a small amount of strong alk effluent?

@Dennis Cartier do you find yourself supplementing calcium separately or is your carx still able to maintain it at your 5ml/min dose?

Hmm, Ca(OH)₂ is kalk. You mention you are using it instead of Kalk. Are you sure your not meaning Sodium Carbonate (Na₂CO₃)? If this is the case, you are using Sodium Carbonate, than yes, you will be dosing unbalanced if you use it without the calcium chloride portion. Over time it will skew your numbers in that case.

Yes, I am able to just use my CaRx to provide all the supplementation. My flow rate is set to 8 ml/min. I also previously did use kalk for dosing at night and at a lower amount throughout the day for the pH boost. To cut down on maintenance I discontinued it and saw a 0.1 pH decrease, so my daily high is now in the 8.3's instead of the 8.4's like before.

 

[Kfactor]

check out fishofhex little bubbler pretty cool idea

 

[Dennis Cartier]

check out fishofhex little bubbler pretty cool idea

I was not able to find it, but I assume it is micro bubbling, where fine air bubbles are pumped into a pump to disperse into the tank. I do something similar with a needlewheel skimmer pump in a fuge barrel that fills the barrel with micro bubbles. It does have a pretty noticeable impact on pH.

I also use this aeration tower that I made. @Saltyanimals you may want to check it out as it could help in your situation.

https://www.reef2reef.com/threads/calrx-aeration-tower-co2-removal-from-effluent-project.849111/

 

[Saltyanimals]

Sorry I mistyped my chemistry. Sodium Hydroxide (NaOH) is what I've been doing on the side in lieu of kalk (CaOH2). That's a whole separate pH experiment.

Glad to hear that even @Dennis Cartier 's 8ml volume is able to maintain his Calcium needs. It suggest CaRX is still a semi balanced Ca and Alk solution even at low volume. I was concerned I needed to monitor Ca more closely for the occasional manual Ca adjustment if I'm dosing smaller higher dKh effluent volume.


And Dennis's DIY link is something else! I'll definitely take a look. Can't say I'm ready to build it myself just yet as I'm now enjoying my new 7.8-8.1 range. Sure I want the 8.3-8.4, but I'll take the win for now. Looking at my charts a significant contributor to my pH is *ME*. My tank is in my home office where I can see a pattern of me working a full day at home providing that extra CO2 for the tank to suck in and drive pH down. Clearly evident on weekends when the office is mostly empty is where I see my tank want to get to 8.2.

Thanks to this thread taking me down the extra tweaking to optimize my effluent, I'm seeing overall pH benefits. Hobbyist are all trying to squeeze and tuner anywhere and everywhere possible. What a great hobby! =)

 

[Saltyanimals]

Hey @Dennis Cartier Question for your ultra potent CaRX juice. Since you’re dosing very little actually effluent, do you find your tank not able to keep up with calcium from the CaRX? I noticed my cal drifting down where I need to dose Ca separately as I tune. Alk is provided as tuned but doesn’t appear it’s a balanced alk and Ca. Thoughts?

 

[Dennis Cartier]

Hey @Dennis Cartier Question for your ultra potent CaRX juice. Since you’re dosing very little actually effluent, do you find your tank not able to keep up with calcium from the CaRX? I noticed my cal drifting down where I need to dose Ca separately as I tune. Alk is provided as tuned but doesn’t appear it’s a balanced alk and Ca. Thoughts?

No, my calcium was 450 the last time I checked. A tad high, but in line where I expected it to be.

Hmm, for your low calcium, your CaRx effluent will always be balanced as produced by your CaRx. So if your calcium is low, than something else is affecting the balance external to the CaRx. Things that can raise alkalinity, and therefore make Ca look low, are dosing nitrates or falling nitrates in a tank that has elevated nitrates. As the nitrates are used up, the alkalinity that was bound during their creation is released. For big shifts of Ca, I would look to salinity to make sure your salinity has not dropped slowly over time as well.

Test error can sometimes be at the root of balance issues as well. Our Ca tests are not very accurate, so the noise from the lack of precision can make it seem like Ca is moving separately from Alkalinity, but it is just the variability in the test, that gives that impression.

 

[Saltyanimals]

No, my calcium was 450 the last time I checked. A tad high, but in line where I expected it to be.

Hmm, for your low calcium, your CaRx effluent will always be balanced as produced by your CaRx. So if your calcium is low, than something else is affecting the balance external to the CaRx. Things that can raise alkalinity, and therefore make Ca look low, are dosing nitrates or falling nitrates in a tank that has elevated nitrates. As the nitrates are used up, the alkalinity that was bound during their creation is released. For big shifts of Ca, I would look to salinity to make sure your salinity has not dropped slowly over time as well.

Test error can sometimes be at the root of balance issues as well. Our Ca tests are not very accurate, so the noise from the lack of precision can make it seem like Ca is moving separately from Alkalinity, but it is just the variability in the test, that gives that impression.

Thank you for confirming. I had no Ca issue for the almost 2 year of using my CaRX as the sole provider of a stable Alk and Ca. So stable that I would test Alk every 2-3 weeks and Ca prob 4-6. It wasn't until recently that I noticed the dip which I immediately retested with same mid 300s. I was close to my regular ICP cycle so that went in and confirmed the low Ca. Triton showed a higher value than my RedSea home test, but still something took it down. Salinity via my Apex continues to be stable in the graphs, but I occasionally retest with a refractometer. Then I knee-jerked to a conclusion that maybe by tuning the CaRX to a highly potently effluent that maybe I'm not getting enough Ca out of the same effluent.

If you're still in the mid 400s and not supplementing Ca elsewhere, then that confirms your low effluent volume continues to be balanced.

Update: After writing the above, I realized that the real cause of my dip may be caused by my pivot to using my CaRX as a secondary provider. I'm experimenting with NaOH dosing as an alternative to kalk for the higher concentration. I had to reduce my CaRX and let the NaOH be the primary provider of Alk (only) since it doesn't provide a balanced Ca solution. The intentional low CaRX effluent limited my Alk contribution, but I forgot the Ca part of the equation so I didn't provide enough Ca needs for the tank. Duh! =)