# Bubbles! Bubbles! My bubbles!



## TankAaron (Aug 8, 2014)

So I was thinking of getting a pump, or powerhead to use in the bucket I do water changes with. I would prepare the ro water, then leave it circulating for a while. My hope is to minimize the pH change that happens in the aquarium after the water has been circulating for a little while.

I mentioned in another thread that my RO water starts at about 6.5 pH, then after it's been circulating for a while in the tank, it is about 7.5 pH. I bought some of Seachem's Acid, and Alkaline buffers. My focus wasn't the pH, it was the KH. But I figured since I was going to buy the Alkaline Buffer, I would also get the Acid Buffer to hopefully keep the pH from going up once in the aquarium. A stable pH is more important, after all, and since the RO water starts with a lower pH, I figured it would be more stable to keep it lower, than to allow it to raise.

Well, I did a major water change today, and I got to play with my aquarium, trimming and tidying. I mixed the buffers according to the instructions, and the water ended up at about 6.8 pH, according to the API liquid tests. I was happy.

A short while after I introduced the water into the aquarium, I can't remember if it was a half hour, or one hour later, I re-tested the water. The water was once again about 7.5 pH. I was not amused.

I was told, in that other thread, that the pH increase happens because of gas exchange with the water circulation. So now I'm thinking of _causing_ the pH change BEFORE I introduce it in the aquarium.

I was thinking of getting a pump, or powerhead, but I remembered I have an Azoo, and Tetra air pumps left over from my last aquariums. I can't remember which was the better pump. I'll figure that out soon enough.

So how long would the shortest amount of time needed to raise the pH to what it will normalize to? I realize I can try it, and test it every 15 min. And I will, but at least I'm creating conversation, don't you think? This is a forum, after all. =b

And a totally unrelated vid, except for the bubbles the air pumps will create.


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## Tugg (Jul 28, 2013)

There is a LOT of information missing from this post.

What size aquarium are you working with?
What's the pH/kH prior to the water change?
Do you inject CO2?
How much water is being changed?
Is it only RODI water, or do you also add tap water?
Do you have any carbonate based rocks in the aquarium (holey rock, crushed coral, etc)?
What's your substrate?
Do you have any driftwood?

There is a LOT that goes into pH, this is why for most people it's simply advised to be consistent in your maintenance instead of worrying about trying to correct something.

Here is my broadly generalized assumption: At a ph of 7.5 in the aquarium, and the fact that it keeps trying to pull back up to this value. I would suspect your kH is somewhere around 4 degrees perhaps higher and you have no CO2 being injected. This would be perfectly normal.

The RO water will almost always start at 7 or less. It has no kH to buffer the atmospheric CO2 its dissolving as it's made. It's pH could easily drop down into the 5s. Once you add some kH this will begin to pull it back up and offset the CO2.

Acid Buffer is a bisulfate salt (an acidic salt). It works to offset the kH by decomposing it into CO2, that then is dissolved in the water and lowers pH. In a sense, it's similar to injecting CO2. By aerating the mineralized RO water you would be outgassing this elevated CO2, effectively wasting the acid buffer and could have just as well not dosed it.

When it comes to RO water, just dose the gH and kH to the desired levels and go ahead and use it. The pH of a planted tank is a constantly moving target that without lab equipment we as hobbyist have no hope of really fully understanding.


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## TankAaron (Aug 8, 2014)

It's my same and only set up:

Only RO water, that starts at 6.5 pH

10g tank

Flourite, and Flourite Black Sand

I am NOW dosing Acid Buffer, and Alkaline Buffer at a 1:1.3 ratio.

Also dosing:

Replenish, two doses, per instructions, which should be aprox. 2 meq/L, or 5.6 dGH, or 100 ppm.

1 AquaClear 20, filled with Matrix, and has a sponge on the intake

some Cabomba Palaeformis, HC, and a few, small Alt. Reineckii Roseafolia

PPS-Pro, now at 2 mL NPK, 1 mL trace, and 2 mL Excel, daily.

Temp. aprox. 78F

1 Betta, 1 Mystery snail


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## Tugg (Jul 28, 2013)

Again, all Acid "Buffer" does is make CO2 out of kH. The CO2 drops the pH a little since there is less kH and now some carbonic acid. This quickly gets depleted and then the pH goes back up.

When Alkaline Buffer is first added to RO water, the pH can be deceptively high. This is because you may not have the typical 3-4ppm of CO2 dissolved in the water yet. All Acid buffer is doing is giving you some false piece of mind my temporarily dropping the pH by making CO2 so you think it's the same as the aquarium.

I would stop using the Acid Buffer and just do my water changes.


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## TankAaron (Aug 8, 2014)

That's very disappointing. Bad for trust, but must be great for sales. /sigh

Thank you Tugg.


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## pandragon (Jul 10, 2014)

Were you ever able to get any kh in there? Before you were just adding straight RO then added some replenish, which i think is just salts that raise GH but not Kh. I think the tests aren't quite accurate because my RO water can be anywhere from 6.5-7.5 when it shouldn't be higher than 7, unless there are other gasses that can drop the ph or interfere with it other than co2. I am not sure what is in alkaline buffer, if it actually adds kh or not, ammonia is basic/low ph but doesn't add carbonate hardness/kh at all, but is also toxic so I know it wouldn't be that, but something similar possibly.


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## TankAaron (Aug 8, 2014)

I first wasn't adding anything. Then when I learned I needed to, I started adding baking soda, only as an emergency, and temporary supplement, until I got my order in.

I got the order in of Prime, Alkaline, and Acid buffers. I did a major water change, and started dosing the buffers. Alkaline Buffer adds KH.

I then got the Replenish delivered, and I started adding that. It adds GH.


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