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Discussion Starter · #1 ·
Why do my plants only pearl when I do a 20 percent water change. I have pressurized co2 system. I have 2 bubbles per second going in the bubble counter and which gets diffused into the aquarium with a reactor 500 from Red Sea. My ph starts out in the morning at 7.1 and goes down to 6.7 with the addition of the co2 daily. I also have a constant 3 dkh of kh. I have a ph controller that shuts off the co2 once it gets to 6.7. So shouldnt my plants pearl with the co2 I am putting in my tank alone? Please help...!!
 

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Maybe the lighting is not sufficient. My tank gets a little bit of sunlight for about 10 mins in the evening and I´ve noticed the plants bubble a lot more during these 10 mins with the added sun light than they normally do during the rest of the day.
 

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Discussion Starter · #7 ·
My numbers

Well my ph controller is calibrated and shuts off at 6.7 and I test my kh and it states 3 dkh everytime....so I don't know?????
 

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Well my ph controller is calibrated and shuts off at 6.7 and I test my kh and it states 3 dkh everytime....so I don't know?????
If you trust both of those numbers, that's just not enough CO2.

When I said something was wrong with your numbers, I was thinking that your CO2 was awfully high in the morning, but I stopped short of going into it because I don't know how much CO2 the plants are putting in at night. I've never done a CO2 measurement first thing in the morning.
 

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Water out of the tap also has lots of dissolved gases in it and the plants could be providing sites for the fresh water to degas. After a water change I see the glass "pearl" all the time.
 

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Do you have a drop checker? The pH/kH/CO2 relationship can only be true if you keep one of the three unknowns constant. You may believe that your kH is constant, but there are other variables in the aquarium that can affect the kH, and thus affect your estimation of CO2.

Unless you have a known 4 dkH reference solution (where there will only be one factor contributing to kH), your plants might not be pearling simply due to insufficient CO2.
 

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Discussion Starter · #14 ·
I have an idea

Since my ph controller is set to shut off at 6.7 should I reset it to shut off at 6.5 or 6.6? I am just wondering because in the co2 / kh chart I believe 6.6 is where I should be with a kh of 3. In the morning right when the lights come on with the co2 my ph reading is 7.1 is that to much of a swing for my fish daily? It is tuough for me because I want my plants to flourish while at the same time make the tank perfect for my fish as well....
 

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You can set your pH controller to a pH of 6.6 or 6.5 with no ill effects. As I mentioned, the CO2/kH/pH relationship will only work if your kH is not being affected by other things. Unfortunately, in the aquarium, there are a variety of other factors that will contribute and affect kH, so using the CO2/kH/pH relationship does not work.

Your best bet is to check your CO2 levels with a drop checker and a calibrated 4 dkH reference solution.

The pH swing is not harmful to your fish. I believe some people have pH swings of 1 (which really means a 10 fold change in acidity or basicity, since the pH scale is logarithmic).
 

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drop checkers are fully accurate as well. People say your are at optimum when your DC is at greenish yellow. Well even at that point i still get bba. Now my DC turns yellow at the 4th hour of my 8 hour photoperiod and i don't see my bba dying. I am tempted to turn it up more but at the same time i'm scared i'll be killing my fish and shrimp.
 

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This might also help!

Tap water in my area has phosphates. When doing 50% water changes the plants perl more because of the higher p levels combined with c02 levels and dosing. I just figured out that during the summer months there is much lower p levels and this was causing problems that had me guessing what was going on. Observation of the plants not perling much right after a water change keyed me into this. I tend to dose p a little less then most people because of the levels present most of the time in my tap water. As a result I increased kh2po4 when doing my normal EI dosing it looks to be getting much better, fast.
something to consider
md!
 
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