Weird Ph Fix

[Forsaken77]

So because my 93 cube has limited surface area, I would always leave the glass tops lid open to oxygenate the water. Even though the tank is next to a door that I would leave open for air, it had low Ph (7.7 at night, 7.8-7.9 day).

After installing an Icecap 3k gyre, I had to close the lid because water would gather on the top of the glass and eventually run down the tank. The gyre was running with the top open as well, so that didn't help up the Ph.

After closing the lid, I noticed my Ph start to rise. Now it's at 8.0 24/7. I think with the lid open it was pulling in more CO2 than Oxygen.

So, and I'm theorizing here, that most people with an open top that have Ph problems are because of the house's CO2 levels and it's making the Ph low. Closing up my tank more helped the Ph. Sounds odd, I know. But my Milwaukee Ph monitors (2 for redundancy) were recently recalibrated and they both show the same number.

 

[saltyfilmfolks]

I think that's plausible. You making oxygen in the tank. If the co2 is higher in the house it could lower it.

Neat!

 

[Fishfinder]

Where are you drawing your fresh air from?

 

[Forsaken77]

Where are you drawing your fresh air from?

This tank is 5 feet from my back door. So I would leave the main door open so air could come through the screen door. But it seems like the water was absorbing more CO2 than it was oxygen with the lid open. The door still gets opened and closed on a daily basis to let the dogs out. I've always had a clip-on fan on the back of the stand to blow air into the stand for the skimmer and dry off condensation.

I also have a Xenia and don't know if that produces oxygen in the water. But to be honest, I have no idea why the Ph is better with the tank closed up more. It still has the opening along the back of the lid. I just think there was more available CO2 being taken in than oxygen. So now that the tank has less atmospheric contact with CO2, the Ph balanced out.

And my tank wasn't fully open top to begin with, even though it's rimless. So people with high CO2 in the house, and a completely open top tank, may be sucking in tons of CO2, lowering the Ph. Limiting that exposure may help the oxygen in the tank. You always have oxygen in the air. So the tank will still get the oxygen. It's just reducing the contact with carbon dioxide that helped.

 

[Fishfinder]

I'm curious because I have ph issues. My thought is that when it takes in O2 it's still interacting with air that has the same concentration of CO2 in it. So it might be less surface area but still the same ratio of O2 and CO2

@Randy Holmes-Farley your thoughts?

 

[Forsaken77]

I'm curious because I have ph issues. My thought is that when it takes in O2 it's still interacting with air that has the same concentration of CO2 in it. So it might be less surface area but still the same ratio of O2 and CO2

@Randy Holmes-Farley your thoughts?

No, it's not the same ratio. If your tank is fully open, no top, then it has all of the surface that is in contact with CO2 and oxygen in the environment, as opposed to a smaller slit in the back of a hood which lessens the waters contact with these gases. Yes, you still have a set amount of CO2 in the house. But the entire tanks surface isn't in contact with it with the hood shut, unlike a fully open top, that's absorbing the CO2 on a larger scale, as opposed to the glass top keeping most of it away.

I asked Randy once before, does gassing off CO2 mean there's more oxygen. And he said no, they work independent of each other. So your surface agitation will absorb both oxygen and CO2. If you have a high concentration of CO2, then it will absorb it at the gas exchange level. The more water and surface area that is exposed to the CO2 air, the lower the Ph will be. The opposite is also true... if it's a highly oxygenated environment, the tank will absorb more oxygen the more water that is exposed to it during surface agitation. So if you have an oxygen rich environment, the closed off hood will do more harm than good. But if it's a CO2 dominant environment, lessening the contact is having a positive effect.

So in my case, there's enough oxygen in the surrounding air and with the skimmer, but a high amount of CO2 also. Closing off more of the surface contact, by closing the hood more, reduced the amount of water in contact with that CO2. Basically there's less CO2 to absorb from the air because I'm depriving the water from contact with it much more. If that makes sense.

 

[Fishfinder]

It does make sense that no surface contact will prevent CO2 absorption. But I your skimmer and sump are pulling in house air it will keep the same CO2 level in the system. Unless you have a way to remove the CO2 for the water.

But I am really no expert. I'll be putting some acrylic over my tank tomorrow to see if it helps. I hope you're right

 

[Forsaken77]

It does make sense that no surface contact will prevent CO2 absorption. But I your skimmer and sump are pulling in house air it will keep the same CO2 level in the system. Unless you have a way to remove the CO2 for the water.

But I am really no expert. I'll be putting some acrylic over my tank tomorrow to see if it helps. I hope you're right

The skimmer and sump are a fraction of the tank. Like I said, this worked in my situation. You may have Ph issues for a completely different reason. I also have my tank by the back door and a fan blowing into the sump area 24/7. So whether the back door is opened or closed, it blows some fresh air by the skimmer and the air is always circulating down there even when the back door is shut because of the fan.

AIso it may be the sum of all parts (the hood, the fan, the back door), as I'm no expert either. But I had low Ph during the summer with the door open all day long. So the tank was obviously pulling in more CO2 than oxygen. Now the door is mostly shut because it's getting colder (NY) and normally my Ph would've went down more, but instead went up since closing the top.

You're obviously welcome to see if it works for you, but make sure to leave an open area along the back of the tank and if you don't have a small clip-on fan to circulate air in the stand, try leaving the stand door(s) cracked open.

Like I said, you may have a completely different problem causing it. Is the piece of acrylic something you already have? Because I would hate for you spend money on something that may not apply.