Problem maintaining alkalinity with co2 scrubber

Tanofthereef

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My biggest struggle right now is maintaining my alkalinity levels without constantly micromanaging my dosing pump. I use seneye to monitor my pH, which for the most part works well. I also use a co2 scrubber recirculating through my skimmer.

ph swing.png


This is my PH from Sept 9 through today. Basically I monitor my pH day to day until it gets below a certain value, usually 8.05 and then replace my Co2 media. Problem is that after replacing my dosing demands goes up to around .3 dKH a day, and slowly decreasing in demand over 2-3 weeks until the average pH drops again. So im having to increase or decrease my kalk dosing every couple of days from 430ml 100% saturation to 360ml~ish over 2-3 weeks.

I've heard of using apex and a solenoid to utilize the co2 scrubber only to maintain a specific pH, but I don't have an apex.

Is there any other option to regulate my pH? Or would finding a balance where my alkalinity is stable over 3 weeks be a better alternative. Which is worse? pH swings or dKH swings.

Would switching to 2 part keep my pH swings more managable?

Any input is welcomed at this point I am frustrated trying to tweak my dosing schedule all the time.
 
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Tanofthereef

Tanofthereef

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So I don't worry too much about the pH now except that it affects my alkalinity. My current strategy is to modify my dosing schedule every couple days to keep alkalinity in line. It works but it is a PITA.

Would you keep your dosing schedule over a few weeks stable and let alkalinity fluctuate then?
 

Flux Capacitor

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I would let the PH fluctuate and keep the all stable. The reason you are using more ALK up when you change your scrubber media is the corals are building their skeletons faster with the higher ph. As the PH trends downwards with the media being exhausted the growth slows. You’re chasing ph with the scrubber media causing the drastic changes over the weeks. As long as your PH is between 7.8-8.4 that’s all you really need to be concerned about. ALK being stable is much more important.
 
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Tanofthereef

Tanofthereef

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So would you say its normal to adjust dosing schedule daily? weekly? bi-weekly?

If my pH goes from 8.4 avg to 7.9 avg over 3 weeks and I dose to keep my alk at 8.0 dKH. How much variation should I allow in my dKH? I suppose over time I will learn exactly how much to dose per pH level. But ideally I'd like to only change my dosing volume once per week max.
 

Flux Capacitor

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If you’re drifting outside of 1 dkh a day you will likely see problems with your sticks. I would keep it as low as possible. I use a trident and a dos pump, and my dkh doesn’t swing more than .2-.3 at any given time.

Again your focus should be on keeping ALK as stable as possible. If it were me I’d take the co2 scrubber off, and dial in the ALK.
 
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Tanofthereef

Tanofthereef

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Okay 1 dkh a day is a very reasonable goal. If I took the co2 scrubber offline I could stop dosing for a month and see no change in dkh. I think I will aim to keep my dkh from changing more than .5 per week and go from there.

Thanks for the perspective.
 
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Tanofthereef

Tanofthereef

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Thats good to hear, I prefer using kalk in a doser as apposed to 2 part.

I had been micromanaging my alk levels to less than .1 daily swing. I will probably extending my testing to every couple days and adjust my dosing every week as long as the change isn't too drastic. Like stated by people in this thread and in others alkalinity stability is key, I might have taken it to the extreme but some day I hope go get that level of stability.
 

Randy Holmes-Farley

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Thats good to hear, I prefer using kalk in a doser as apposed to 2 part.

I had been micromanaging my alk levels to less than .1 daily swing. I will probably extending my testing to every couple days and adjust my dosing every week as long as the change isn't too drastic. Like stated by people in this thread and in others alkalinity stability is key, I might have taken it to the extreme but some day I hope go get that level of stability.

Just to challenge that assertion about alk stability being more important than pH, folks might want to rad this discussion:

 

Reefinmike

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Just to challenge that assertion about alk stability being more important than pH, folks might want to rad this discussion:

You published that a month after I bought my alkatronic to follow the new trend of flatline alk... i was crushed I spent $900 on a fancy pH probe .

I’m two months into my experiment dosing lye for higher pH and just started the final phase; switching between lye and soda ash to maintain alkalinity AND pH stability. It’s all anecdotal but so far I’m confirming your theory. https://www.reef2reef.com/threads/chasing-ph-stability-and-alkalinity-stability.779022/
 
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Tanofthereef

Tanofthereef

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Well I think i found my solution to maintain stability of pH and dKH without an apex.

I confirmed with support at felix smart controller that with a firmware update newer model seneye monitors are compatible with their software. So I bought just the controller to work with my existing seneye. Felix has some logic based software so I am going to set up a solenoid in conjunction with my co2 scrubber to maintain my pH between 8.2 - 8.25.

Hopefully it all works out and I can take my laptop off seneye duty. Best part is the felix controller with added functionality wasn't much more expensive than the web server box for seneye so a win-win for me if it works.
 

SecondCityCorals

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Felix has some logic based software so I am going to set up a solenoid in conjunction with my co2 scrubber to maintain my pH between 8.2 - 8.25.

This is the best way to do it. I use the Trident and Apex to control the digital regulator on my co2 tank. This pegs my CaRx reactor solidly at 6.5. I then have the Trident test my Alk ever 6 hours, and depending on results either turn my dosing pump on or off. This keeps my alkalinity in a pretty stable range, while also being able to dynamically account for fluctuating coral demands.

Your co2 scrubber is causing alk drops because your corals are happy and growing more. Please, don't perpetuate the idea that chasing the PH wrong. If your increased PH level was wrong, your corals wouldn't be using more alkalinity and growing faster.

The automation and ability to dynamically dose alk/calc/mag from a CaRx is the best route to take.
 
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Tanofthereef

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Aside from the actual values being off between my two monitors, which I should probably check against a test kit + calibration liquid. My new felix controller with motorized ball valve has been working perfectly.

When I first set up the felix monitor it was around 8.25 pH while my original monitor was around 8.28. Then over a few weeks the felix slowly went down to 7.9 which I thought was the slide / co2 scrubber media going out. But my original monitor stayed at 8.28. Well I'm not sure what the deal is but after putting my ball valve to maintain pH at 7.9 on my felix monitor it would keep it within .01 pH, meanwhile my seneye monitor maintained a stead 8.22 pH with .02 variance for 5 days. So I felt comfortable moving my seneye monitor to my new tank and relying on my felix monitor for the pH in this tank. I thought about using the calibration setup in felix to change my pH to 8.22 to match but as of now the app's IFTTT controls go off the raw value not the adjusted.

20201211_132858.jpg
Screenshot_20201231-114404_Chrome.jpg


For now I will keep testing alk and watching the pH values to see how steady everything reacts to the new setup.
 
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Tanofthereef

Tanofthereef

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Well I bought a hanna probe and calibration fluid to compare to my seneye monitor readings. I think I trust the freshly calibrated hanna probe over the seneye slides. But my results were this:

(Freshly calibrated hanna probe in 7.01 and 4.01 soltuion)

Seneye monitor with 15/30 days left slide reads 7.81 - hanna probe reads 7.79

felix monitor with 29/30 days left slide reads 8.17 - hanna probe reads 8.03.

As far as the valve and maintaining my ph at a precise level, I think that is working as I intended, but it's surprising that my felix monitor is a full .14 off while the seneye monitor was .02.

The only remaining problem to solve is that over time the seneye slides lose their reading somewhere from the low "8.2 to 8.3 range" to around 7.75 by the time day 30 is up. So I will have to change my if then rule periodically through the slides life, or replace my slide every 15-20 days. Hopefully the felix controller will come out with a compatible probe I can use that will have longer calibration periods than every 15-20 days.

In hindsight having a new controller on the market is exciting, but I think the apex would have been better suited for this application currently until felix brings a compatible probe.
 
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