Correlation between Alkalinity and pH?

[Ojala]

Hi everyone,
I have a 300 gallon mixed reef system, and I am trying to make my tank a tad more stable/automated since I am traveling out of state for weeks at a time due to school. I am switching from a bubble magus dosing system (using biotech two part solution) to a korallin calcium reactor (running ARM coarse media), which will be monitored by a Neptune Apex system (with two pH probes, one for the reactor itself and one for the tank). I am brand new to calcium reactors and the Neptune products, but I will be getting some help from a friend who has this exact same setup for years now. So my main question is, how strong is the correlation between alkalinity and pH, meaning if my calcium reactor/Neptune system keeps my pH at 8 for example, will my alkalinity also remain constant or will it fluctuate? and if will fluctuate, will the fluctuations be large, or small enough not to worry about?
Any clarity on the matter would be greatly appreciated.
Bests,
Ojala

(Side note: I also understand that pH and alkalinity measure two totally different things, but it is my understanding that they correlated, however i may be wrong.)

 

[Ojala]

Bump

 

[Cory]

You cannot have confidence of alkalinity based on ph because Co2 in the air will lower ph ignoring the alkalinity. Your ph could be 7.8 but alkalinity could be anywhere from 5 to 11dkh. If thats what you were asking.

 

[Ojala]

You cannot have confidence of alkalinity based on ph because Co2 in the air will lower ph ignoring the alkalinity. Your ph could be 7.8 but alkalinity could be anywhere from 5 to 11dkh. If thats what you were asking.

Yes, that's exactly what I'm asking about. So you're saying the ambient CO2 levels in the air will be enough to affect a 300 gallon system enough to change its pH significantly? That seems a tad odd. Besides frequent drop wise Alk tests or the new trident system, is there anything I can use to keep my alk stable while I'm away for weeks at a time?

 

[C. Eymann]

Yes, that's exactly what I'm asking about. So you're saying the ambient CO2 levels in the air will be enough to affect a 300 gallon system enough to change its pH significantly? That seems a tad odd. Besides frequent drop wise Alk tests or the new trident system, is there anything I can use to keep my alk stable while I'm away for weeks at a time?

Yes, CO² levels definitely can effect pH, one pretty funny story is that a father reefer left for vacation and decided to leave his teenage kids home alone, he could tell they were having a lot of people over because his Apex notified him of his pH dropping.

 

[JimWelsh]

So you're saying the ambient CO2 levels in the air will be enough to affect a 300 gallon system enough to change its pH significantly?

Yes.

 

[Ojala]

Yes, CO² levels definitely can effect pH, one pretty funny story is that a father reefer left for vacation and decided to leave his teenage kids home alone, he could tell they were having a lot of people over because his Apex notified him of his pH dropping.

That's crazy lol. So do you know of any way I can keep my alk under control while I'm away? If it helps the tank is located in a room that people don't really go in that often.

 

[lmm1967]

the secondary PH probe you have will be used in the reactor to help you dial in the rate of water & CO2 being added to the reactor.

The PH of your tank will be monitored so that if your PH gets too far out of range the apex will stop feeding water to the reactor (which in turn will prevent effluent from the reactor getting into the tank).

PH will not be used to keep ALK consistent - you'll need to do that by testing and dialing in the flow rate to your CA reactor.

 

[lapin]

For me once the reactor is stable ( feeding my system the correct amount ) my alk remains stable. My PH will change depending on how much outside air comes into the room or how much my a/c comes on, not my reactor.

 

[Ojala]

For me once the reactor is stable ( feeding my system the correct amount ) my alk remains stable. My PH will change depending on how much outside air comes into the room or how much my a/c comes on, not my reactor.

How long did it take you to dial in your reactor?

 

[lapin]

It took about 3 weeks.
I have a Geo's old model like the CR818. Reborn media. Reactor PH 6.6. I recommend you start higher and work your way down. Never used ARM media
I control the CO2 (PH) with a different bubble counter that's a bit more precise than what comes on the reactor.
The CO2 is only set to be shut off by a solenoid if it drops below my safety factor. I dont want to create media mush. I also dont want the solenoid to be off / on a lot.
The effluent is a fast drip, almost a stream into my filter sock part of my sump.
You have to play with the drip rate / bubble rate vs tank consumption.
This might help depending on how you plan on having it set up;
If your alkalinity level is holding where you want it to be, you're reactor is dialed in to match consumption. That's a good thing. If alkalinity is rising over several days, it means that you're dosing too much. In your system, you might slow the bubble rate down a little to raise the pH inside the reactor just a little to slow dissolution down. If alkalinity is falling, then increase the bubble rate just a little to lower the pH inside the reactor.
If you're alkalinity is holding, but is a little lower than you want it to be, then manually dose alkalinity to raise it to a new steady state level and leave your reactor dialed in where you have it now. If it's higher than you want it to be, then unplug the solenoid on the reactor to stop the CO2 injection and just let the levels drift downward to your target level.
Since your friend has one, that will be a big help.

 

[Randy Holmes-Farley]

Yes, that's exactly what I'm asking about. So you're saying the ambient CO2 levels in the air will be enough to affect a 300 gallon system enough to change its pH significantly? That seems a tad odd. Besides frequent drop wise Alk tests or the new trident system, is there anything I can use to keep my alk stable while I'm away for weeks at a time?

Definitely. Home CO2 levels have a big effect on pH at fixed alk.

 

[Kjames]

Definitely. Home CO2 levels have a big effect on pH at fixed alk.

This is something I am learning. I have a 90 gallon system in my office. Ambient CO2 goes up as high as 1200 during the day with 11 people coming and going. My recirculating CO2 (BRS standard canister) scrubber helps but not as much as I expected. The pH rise on Saturday when the office is empty is quite obvious. Wondering if my skimmer (Reef Octopus 150SSS) just doesn't have the hp to drive the scrubber or the scrubber is only so effective. Here's a good example of Thanksgiving week when the office was empty thursday through the weekend.

 

[lapin]

The issue we have with our calcium hydroxide/sodium hydroxide scrubbers is they are way to small to do much good.
If you look at commercial units that are set up to do whole rooms they are much larger.

Welltech HVAC AHU CO2 purifier, CO2 filtering system, Office CO2 purifier

 

[Kjames]

That puts it in perspective. Those things are huge.

I'd enjoy hearing what results others are seeing with hobbyist CO2 scrubbers. Skimmer function and amount of surface agitation in the sump/display play into it. Anyone have more compelling results? Changing pH by 0.12 isn't very exciting.

 

[Bitcoin Reefer]

Yes, CO² levels definitely can effect pH, one pretty funny story is that a father reefer left for vacation and decided to leave his teenage kids home alone, he could tell they were having a lot of people over because his Apex notified him of his pH dropping.

Lol!!!!