Experimental results, need feedback


Guru Class Expert
Jan 22, 2008
Vista, Ca
This is what let me to do the experiment. From day to day the tank is pearling or not pearling when I get home. Mind you I turn the co2 on at 7 am and don’t usually get back home until 7pm so I did not have a clear idea of the time the pearling would start on days that it was pearling when I got home. So like many I keep trying to figure out what the heck is making it pearl so I can recreate that situation. It just so happened that about a week ago I was home most of the day studying and the darn tank did not pearl all day long. So I started ruling things out that could be limiting factors … And it hit me, the days that the tank was pearling were days when the co2 bps was too fast to count (I had my wife turn it up the co2 while I was at work and she didn’t know what to look for) the drop checker was solid yellow and the fish looked fine. So for 6 days I tried 3bps for one day and let it run all day and then the next day cranked it up. Sure enough, by the afternoon on the days when the bubbles were coming out fast the tank was pearling like crazy and the drop checker was back to yellow.

Is this due to the fact that the saturation of co2/o2 in the water is so high that the bubbles are seen due to degassing? Or is the co2 just at a “good level” to cause this? Is this a perfectly normal?

What do you guys think about the above experiment results?

Tank specs:
My tank is 60gals but about 50gals of water give or take with all the gravel and driftwood ect. I have two spray bars mounted along the back wall of the tank creating a swirling motion from front to back that moves water across all the plants nicely so I know the co2/nutrient mixture is good. Its not breaking the surface of the water but slightly agitates it so the skum stuff does not build up. My fish load is low. Plant load is between med-high. EI dosing, and when I see bba starting I dose 10ml excel daily.

Tom Barr

Staff member
Jan 23, 2005
Sometimes simple observations and a good reference point is all you need.
The plants obviously looked pretty nice?

Now the question is how where the fish?
Are they okay with this?
Are they acting well?
Do you have a high fish load?

I think many folks that are not growing their plants like weeds tend not to have enough CO2 to dramatic growth, but many fear for their fishes' health and rightly so. But some careful eye balling of the tank, the plants and the fish will really help.
CO2 increases should always be done very slowly and make sure that the fish are in good shape.

The pearling is not due to CO2 degassing, rather, intense pearling from photosynthesis.

"and when I see bba starting I dose 10ml excel daily."

That's the other dead give away.

You might not need at much CO2 as you added, but something in between.
I'd go for about 1-2 bubbles a second and see.

Tom Barr