Apex: Using current pH value to set CO2 run time

chvvkumar

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Hello all, I am using my Apex for freshwater CO2 control. I want to see if it is possible to write a program that would:

1. Take a reading of pH at 10am (for example pH = X)
2. Turn ON CO2 until pH drops to X-0.75
3. Turn off CO2 until pH rises back up to X-0.5 and turns the CO2 back on

I have step 3 running right now but with water changes, my pH swings and throws off my program:

Code:
Fallback OFF
If pH > 6.85 Then ON
If pH < 6.80 Then OFF
If Time 17:30 to 09:45 Then OFF
If pH > 9.00 Then OFF
If Output Maintenance = ON Then OFF
If FeedA 015 Then OFF
 

ZombieEngineer

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It can technically be done in blocks, but it would take 2 virtual outlets per block and gets really complicated really quick and is almost certainly not worth the hassle.

Ex

pH6970
Set OFF
If pH < 7.0 Then ON
If pH > 6.89 Then OFF
If Time 10:01 to 09:59 Then OFF
Min Time 999:59 Then ON

pH6970control
If pH > 6.5 Then ON
If pH < 6.25 Then OFF
If Output pH6970 = OFF Then OFF

Actual Outlet
Fallback OFF
Set OFF
If Output pH6970Control = ON Then ON
If Output pH6869Control = ON Then ON
(All other sensing blocks)
If pH > 9.00 Then OFF
If Output Maintenance = ON Then OFF
If FeedA 015 Then OFF
 
Last edited:
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chvvkumar

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It can technically be done in blocks, but it would take 2 virtual outlets per block and gets really complicated really quick and is almost certainly not worth the hassle.

Ex

pH6970
Set OFF
If pH < 7.0 Then ON
If pH > 6.89 Then OFF
If Time 10:00 to 09:59 Then OFF
Min Time 999:59 Then ON

pH6970control
If pH > 6.5 Then ON
If pH < 6.25 Then OFF
If Output pH6970 = OFF Then OFF

Actual Outlet
Fallback OFF
Set OFF
If Output pH6970Control = ON Then ON
If Output pH6869Control = ON Then ON
(All other sensing blocks)
If pH > 9.00 Then OFF
If Output Maintenance = ON Then OFF
If FeedA 015 Then OFF

I need to learn about blocks but like you said, might not me worth it. Here is my problem I am trying to solve. The starting pH is different every day and a static value is almost always wrong in my use case:

1662348498070.png
 

jahnje

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I wouldn't stress over it. This is the natural pH swing of my tank with nothing but lights. When I've got the CO2 hooked up to things all I do is flatten it out, and push it down into the mid to low 6's with a simple program. As long as your KH is stable your tank will be stable. I keep my KH around 3 which in RO gives me an average Ph of around 7.3 .

Code:
Fallback ON
Set ON
If pH < 6.50 Then OFF
Defer 000:30 Then OFF
Defer 000:30 Then ON


Screen Shot 2022-09-27 at 8.45.11 AM.png
 
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chvvkumar

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I wouldn't stress over it. This is the natural pH swing of my tank with nothing but lights. When I've got the CO2 hooked up to things all I do is flatten it out, and push it down into the mid to low 6's with a simple program. As long as your KH is stable your tank will be stable. I keep my KH around 3 which in RO gives me an average Ph of around 7.3 .

Code:
Fallback ON
Set ON
If pH < 6.50 Then OFF
Defer 000:30 Then OFF
Defer 000:30 Then ON


Screen Shot 2022-09-27 at 8.45.11 AM.png
I'm using this in a planted tank, which is why the need to control the starting value. In the end I actually did something else. I added an air stone to increase the out gassing at night. Seems to have taken care of keeping a constant starting pH at the begining of the photoperiod.

1664395293432.png
 

jahnje

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I'm using this in a planted tank, which is why the need to control the starting value. In the end I actually did something else. I added an air stone to increase the out gassing at night. Seems to have taken care of keeping a constant starting pH at the begining of the photoperiod.

1664395293432.png
Guess I wasn't clear. Mine is a freshwater planted tank as well. Though very heavily planted, which is why the swings are so big. I also do daily water changes. I guess my point is don't stress too much over Ph swings, the fish don't care, and I don't think the plants do either. It's really about the keeping the amount of buffer/KH stable, and making sure you have enough of everything in the water to not limit. Anyway, as long as you're having fun! Do what works for you!

I'm curious how you do your water changes. I pump out about 5% per day, fill to top with RO, then DOS in the appropriate amount of concentrated re-mineralization for that removed 5%.
 
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chvvkumar

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Guess I wasn't clear. Mine is a freshwater planted tank as well. Though very heavily planted, which is why the swings are so big. I also do daily water changes. I guess my point is don't stress too much over Ph swings, the fish don't care, and I don't think the plants do either. It's really about the keeping the amount of buffer/KH stable, and making sure you have enough of everything in the water to not limit. Anyway, as long as you're having fun! Do what works for you!

I'm curious how you do your water changes. I pump out about 5% per day, fill to top with RO, then DOS in the appropriate amount of concentrated re-mineralization for that removed 5%.
Ah sorry, I misunderstood. My tank is heavyly planted too. I do about 75% changes every week. I am doing EI dosing so 50% is the recommended amount but my water is super hard and I use an ATO with normal tap water so the kH creeps up through the week via. ATO water. This also makes dropping pH, even 1 unit, hard. Max I can do right now with a lot of CO2 is about 0.75 drop.

I am figuring out my RODI install right now so that I can use a DoS to do what you are doing. Ideally, I want to transition to using RODI water in my tank and buffer it.
 

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