Can someone school me on PH?

RussC

RussC

Active member
Tank born on 8/29. And my PH has remained constant within the range of 7.5-7.8. Very consistent. But at this point I'm able to maintain all my parameters with water changes due to the light bioload. Based on suggested parameters, I'd like to see my PH move into the 8.0-8.3 range. So I guess my questions are: What seems to be the difference makers when it comes to PH? Will that increase as my bioload increases and I begin to have to supplement to keep up with corals, etc? Or will I naturally see a PH increase as the tank matures? Some of you veterans out there probably have a comment or two. And I know one that I can always count on chiming in.
 
They will tell you not to worry about PH. I say wait a month and then re test. See if it goes up. I do prefer mine around 8.1-8.3, I've never had to add anything to manipulate it but I do notice that more frequent water changes (20% 1 x per week) keeps it in the 8.3 range.
 
In an aquarium, pH (its not PH :) ) is mostly a function of CO2 content of the ambient air the tank water is in contact with. When CO2 dissolves in water, it forms carbonic acid. Carbonic acid is a weak acid that lowers the pH of the water. There are minor contributions from organic acids that regenerated by metabolic processes of living stuff (mostly bacteria). But most of those are short lived.

Most of the time, pH of your tank will improve somewhat (due to algae growing in main tank ) but I highly doubt it will increase by 0.4 pH. Every system would try to revert back to equilibrium, an aquarium is not any different. It will also try to go back to its equilibrium state, which is determined by the amount of CO2 in the air.

There are ways to reduce the CO2 content of a tank that increase pH. One way is to add a fuge with some type of algae. Since algae are photosynthetic, they use CO2 and therefore increase pH. Another way is to allow you skimmer to suck air directly from outside (since indoor co2 is generally higher) or connect a CO2 scrubber to the skimmer. But keep in mind these only work if your skimmer contributes for the majority of the gas exchange. This generally this requires an over sized skimmer.

All in all you dont need to keep an eye on pH as long as other parameters are in check. Higher is better but lower 7.8 is not that bad either.

There are products that are advertised to raise pH. Dont use those, as I explained before, you cant change equilibrium. It will only raise pH short term and the tank will eventually revert back to equilibrium pH. If you continue adding those products to compensate, you will nuke alk and most likely cause calcium to precipitate as CaCO3.
 
One way is to add a fuge with some type of algae. Since algae are photosynthetic, they use CO2 and therefore increase pH.

I think I'll add a fuge at one point or another, if for no other reason than I want to give it try, see how things work with it and gain a little experience working with one. Amazing how quickly you take up space in a sump, though. Would have to be a small footprint style. But that's a wishlist item. That list gets longer by the day!
 
You could add an air pump (stone) to the system. It can get a little messy with the salt creep but it should help. Just a thought.
 
RussC said:
What does an air stone do for PH?
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Nothing besides make a mess if you already use a skimmer or have good water circulation with good air/water contact at the surface of your tank. If you don't have good water circulation, that would be a good place to start. Add a power head and point it towards the surface so the circulation breaks the surface a bit. First step would be to get your tank fully saturated with ambient air if its not already.

Do you use a sump? Skimmer? Where do you live? If its cold there and your house is closed up tight most of the time, and you have a family, your house could be high in CO2. If that's the case, using a CO2 scrubber on the air inlet to your skimmer is a good way to increase the O2 content going to your tank.

In general, I would advise against adding a macro algae fuge primarily to control pH. It will help during the day, but when the lights go off at night, guess what? The diurnal swing will hurt your tank more then the consistently low pH.

Another big question (probably the biggest right now), what method of measuring pH are you using? One of the big reasons people say don't chase pH, is our hobby methods of measuring pH are not that great as a general rule.
 
CO2 in the water drives the ph down. I use a CO2 scrubber. An air stone really won't help much if the household air is high in co2. With the house closed up and the AC on my CO2 level in the house pushes 800. With the windows ope it will get down to 300-400. Some people run an airline to the skimmer to the outdoors.
 
ReeferNoob4ever said:
I do notice more growth, especially from my stony corals if my PH (don't be a dork) is higher.
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More growth may be because of a higher level of alkalinity which is used for SPS and LPS. Additions of alk will cause an increase in dkh but ph will settle back down.

DO NOT try to increase ph by adding alk (buffers)
 
Agree with most observations - though don't use an airstone, it will do nothing other than make a mess. If you have persistent, and accurate low PH then better room ventilation can help. I never found fresh air to the skimmer to do anything, though room ventilation did. Reverse lit refugium can also help as can using Kalk. Never use PH adjusting chemicals.
 
hkgar said:
CO2 in the water drives the ph down. I use a CO2 scrubber. An air stone really won't help much if the household air is high in co2. With the house closed up and the AC on my CO2 level in the house pushes 800. With the windows ope it will get down to 300-400. Some people run an airline to the skimmer to the outdoors.
Click to expand...

This is a very interesting point. I live in South MS. After Katrina, I enclosed my entire home in spray foam. Its like a cooler, sealed off tight. Best money I ever spent. Electricity bill is incredibly cheap. The benefit is conditioning is incredibly efficient and the house holds its temp very well. Downside is, the house holds its air very well, very tight. When I have a fire in the fireplace (That one cold day of the year) I have to crack a window so it can draw air inform outside. Even with the built ventilation of the fireplace, I still have to do it. So to your point, I wonder just what my CO2 level is. How in the world do I measure that?
 
RussC said:
This is a very interesting point. I live in South MS. After Katrina, I enclosed my entire home in spray foam. Its like a cooler, sealed off tight. Best money I ever spent. Electricity bill is incredibly cheap. The benefit is conditioning is incredibly efficient and the house holds its temp very well. Downside is, the house holds its air very well, very tight. When I have a fire in the fireplace (That one cold day of the year) I have to crack a window so it can draw air inform outside. Even with the built ventilation of the fireplace, I still have to do it. So to your point, I wonder just what my CO2 level is. How in the world do I measure that?
Click to expand...

Just take a cup of water from your tank and leave it outside (uncovered) for several hours (best overnight), or maybe half and our if you have an airstone to use outside. After it equilibrates with the outside CO2, measure the pH. If CO2 is your problem, pH of the water should be higher compared to your tank pH.
 
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