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O.K. I don't want to sound negative or for people not to like me, because I really do like you all, but I think in most cases what appears to be pearling after a wc is not pearling at all. When you open your tap and run water you could see all the little bubbles. That's because the water is highly pressurized coming out of the tap and when the pressure is realized all the compressed o2 gas comes out. So what you are seeing in your aquarium, especially if you are refilling your tank right from the tap via a python the pressurized tap water is going into water with no pressure so all the little o2 bubbles start to escape and of course many will attach to the plants and everything else, but on the plants it looks like pearling. Believe I had some rotala stems that were not doing anything, but after a wc it looked like they were pearling.

My Scapes

There still seems to be some confusion as to what "pearling" actually is. True pearling is when the bubbles of O2 are produced by the plants themselves as part of photosynthesis. The water has become O2 saturated through the output of the plants alone.

Trapped bubbles from a water change or bubbles streaming from a cut stem or broken leaf would not be considering pearling. Neither of these really tell us anything about what the plant is doing.They're just bubbles.

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Some days you're the pigeon and some days you're the statue.

Remember that age and treachery will always triumph over youth and ability.

In my case, one additional factor that results in lots of gas bubbles appearing is this.

The water I use starts life in the cold tap. Which, in winter, is pretty cold. So I add boiling water from a kettle to bring it up to temperature. Even though it gets stirred a lot, and I spend time making sure that the temperature equalisation is within a fraction of a degree of the remaining water in the aquarium, there's still extra dissolved gases that take time to exit from the water. Remember, gas solubility decreases as temperature increases. So in my case, I'm warming up cold tap water, which has a fair amount of dissolved gases in it, and these gases then start to leave the water as the temperature rises. But they don't leave all in one big fell swoop. The gases take time to leave. Even though I spend time preparing the water, there's still some excess gases present when it's finally added to the tank. These gases will eventually leave, but they'll be a little tardy about doing so. Consequently, the gases, as they try to leave solution, nucleate around any sites present in the aquarium that allow them to do this, such as plant surfaces. Hey presto, plants with bubbles on them.

However, the effect, even given the above, seems to be minor in my aquaria. I don't get 'pearling' in spectacular fashion. However, in the breeding aquarium, I have seen pearlng taking place the moment I added four new Panda Corys to it and they started awakening the semi-dormant foliage with their CO2 and nutrient output (over and above the small amount that was there because I was 'seeding' the aquarium with small amounts of fish food to keep the filter ticking over).

Anyway, I'll let this thread continue to run and see what comes up.


Panda Catfish fan and keeper/breeder since Christmas 2002

i didint say that the water should be saturated with O2 , i meant what u just cleared out

BUT if anyone has recently trimmed his plants he would notice that bubbles would start to rush out ,npw thats real pearling.

Well not really. You cut a plant and the oxygen it's producing internally will come rushing out through the cut. Generally this is visible because it's coming out faster then the water can dissolve it, so it may not indicate oversaturation of O2 in the same way that pearling does.

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Some days you're the pigeon and some days you're the statue.

Remember that age and treachery will always triumph over youth and ability.

I have that happen on my Wisteria and my mellon sword.

55G Planted tank thread
19G Container Pond
[IMG]http://i4.photobucket.com/albums/y118/Wingsdlc/Ric

tetratech mentioned that the plants are not pearling , its just the gasses sticking onto anything and bubbling out , well that is partially correct , BUT if anyone has recently trimmed his plants he would notice that bubbles would start to rush out ,npw thats real pearling.

Very interesting.......Co2 in the tap water. Could be great for a planted tank!

55G Planted tank thread
19G Container Pond
[IMG]http://i4.photobucket.com/albums/y118/Wingsdlc/Ric

When using the tapwater I let most of it sit to degas but I found adding a small amount of straight tapwater once or twice a week really increased plant growth without dropping the ph too fast. Changing all the water with tapwater killed one of my farlowellas and upset the fish quite a bit. I learned I could do about 2-3gallons out of a 15g water change on a 55g tank or I could add 1-2gallons straight to the tank without doing any harm to the fish.

Plant growth on weeks I added tapwater compared to when I didn't was at least 25% more but on some plants up to 50% more. When I hooked up co2 the difference between using co2 filled water and degassed water was barely noticeable so for fish safety I mostly stopped using straight tapwater. I did see pearling in the tank once before I hooked up co2. I'd done a big water change early in the day so the plants had the whole day to use up the co2 and fill the tank with O2. The co2 concentration of my tapwater is somewhere around 50ppm. It foams when you fill a glass.

For various other problems with the tapwater I started using ro water which doesn't seem to be saturated with either O2 or CO2 so now neither of those applies to me.

Sham,

Well wouldn’t it have been nice if for once we found that one solution solves one question? But no, I guess nothing in this hobby is that easy .

You for sure gave an explanation that I would not have thought about, adding CO2 to the tab water. Makes perfect sense for the situation you describe. When answering the question raised by the thread title this is a point to consider. It could not have been the case in my situation though, as my dissolved CO2 from the tab is only 5ppm.

I am not sure if tetratech’s explanation and mine are completely separate entities. I conclude that the addition of O2 during the water change will cause O2 saturation in the tank water and as such additional tiny pearls will form that attach themselves to many things (but not to the gravel in my tank). The plants that are in the photosynthesis process will add more O2 (they always do, even under poor growth conditions as long as there is any growth). With O2 not being able to dissolve into the water as it is saturated, it forms bubbles on the leaves and it appears as if they were going really strong – which is not the case (in this case ) anymore than normal.

The interest here was to find out if pearling after a water change is an indicator for additional growth in plants indicated through the pearling. Now, your explanation might just conclude in this being true. I would assume that in a tank with all other factors besides proper CO2 in place (namely lights and nutrients), stronger growth would be observed when CO2 enriched water is added during the water change. BTW, the opposite should be true in CO2 enriched tanks. When low CO2 tab water is added the growth should temporarily slow down as the ppm in the water would fall and have to build up again.

Thanks for your valuable input sham ,

Ingo

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Proud Member of the New Jersey Aquatic Gardeners Club

In tetratech's example the gas is from the water and settling on the plants whereas I thought above you decided it was the gas coming out of the plants and not dissolving into the water. As I understand it pearling is when the 02 gas coming out of the plants is visible on the leaves and not when gas from the water is leaving solution to sit on the leaves. Tetratech's example would not technically be pearling but even if you presaturate the water with O2 filled tap water and then see the bubbles coming out of the leaves it's still called pearling. There's actually 2 different explanations in this thread for bubbles after a water change but one explanation can result in bubbles even if you don't have plants.
Then there's my odd tapwter that is saturated with co2 not 02 because the water is too hard to filter so they use the co2 to lower the ph instead of softening it.


Last edited by sham at 14-Dec-2005 23:03

tetratech,

I thought we concluded with your results a few posts earlier, before the much more important discussion about our hair started .

Basically we said that it is a question of O2 saturation, not better plant growth.

Ingo

Last edited by LITTLE_FISH at 14-Dec-2005 10:13

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Proud Member of the New Jersey Aquatic Gardeners Club

Hmpf... some of us like to hold on to our illusions, tetra... ]:|

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Back in the saddle!

Gang,

Either I never really listened when someone explained this to me or I haven’t gotten a proper answer to it yet. But I became very curious the other day as to why the plants pearl so nicely when I do a water change.

I believe that the answer I heard was that tab water contains a lot of dissolved carbon dioxide, but for some reason that wouldn’t make any sense to me. Here is why:

My tab has a ph of 7 and a KH of 1 to 2 DH, which means it cannot hold more than approx. 5ppm of CO2. My tank, on the other hand, has a ph of 6.6 and a KH of 4 DH, which means it holds about 30ppm. Now, if I replace 50% of the water with tab water, shouldn’t I see significantly less pearling as the CO2 rate goes down? Nevertheless, after a water change the tank pearls like mad.

The only explanation I could come up with would be that the tab water contains a form of liquid carbon, like Flourish Excel, that does not influence the ph. But that doesn’t sound reasonable.

Now, here is my own wild theory of what is happening (and I am a chemistry loser): That is not CO2 that is bubbling there but dissolved oxygen. The tank current swirls these molecules around and eventually some will attach themselves to objects, such as leaves. Additional molecules will be attracted to these and eventually a bubble that is big enough to be seen will have formed. And that’s it – no CO2 but O.

Please either straighten me out or let me know what you think,

Ingo

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Proud Member of the New Jersey Aquatic Gardeners Club

That would explain why I am doing way better in school now than I did back in high school! 3.81! Compared to my used to be normal C's.

Sorry to get the rambling going..........

55G Planted tank thread
19G Container Pond
[IMG]http://i4.photobucket.com/albums/y118/Wingsdlc/Ric

Guys,

Has nobody told you yet that balding is a sign of superior intelligence? The brain cells need more room and as such push the hair follicles out of the skin .

Ingo

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Proud Member of the New Jersey Aquatic Gardeners Club

I plan on buzzing my head someday. My fiancee doesn't really like the idea of it but I just can't see myself walking around with no hair on top and tone on the sides(just like Bozo the clown(how ever you spell his name)). I think I am probably going to move down a little father south and I wont be so cold if I do the buzzing.

55G Planted tank thread
19G Container Pond
[IMG]http://i4.photobucket.com/albums/y118/Wingsdlc/Ric

It's Ok wings, as Ingo will no doubt point out I'm somewhat "follically challenged" myself.

More so now, as I decided it would be fun at the weekend to shave my head. Wife thinks I look like a hitman.Fish swim away and hide behind the plants in case I'm going to put the whack on of them. It's a nice feeling though in this tropial humid climate.

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Some days you're the pigeon and some days you're the statue.

Remember that age and treachery will always triumph over youth and ability.

Hey now!!!!! There is nothing wrong with loosing your hair!!! Dang it all!! I am only 23 and it is getting kind of thin on top!! GRRR Grandpa its all your fault!!

Very neat thread though. I have wondered the same thing. After a water change I normally start getting some pearling on some of my plants. I was figuring most of it was from the bubbles that the new water was making. In my case it probably is.

55G Planted tank thread
19G Container Pond
[IMG]http://i4.photobucket.com/albums/y118/Wingsdlc/Ric

and the brain freezes over.

Not enough hair to keep the head warm ]

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Some days you're the pigeon and some days you're the statue.

Remember that age and treachery will always triumph over youth and ability.