Does your drop checker do this?

ccLansman

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Jan 22, 2008
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Does anyone else have drop checkers in their tanks that stay green or yellow 24/7. Mine do even after running o2 into the tank all night. Is this a sure sign that im not adding enough o2 at night to keep up with the plant/fish demands? Or are the drop checkers not able to return to blue?

Thanks
 

SuperColey1

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Feb 17, 2007
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If you are running CO2 24/7 (I assumed this because you as you run it all night) then it will stay a reasonably consistent level albeit a little lower toward the end of the photoperiod and pretty high at the start of the photoperiod.

Because you are unning 24/7 then it will never go down to a blue level.

If we run on solenoid then the drop checker usually returns to a murky blue but not the same as a fresh solution.

AC
 

VaughnH

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Jan 24, 2005
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You have to replace the solution in the drop checker about every week or two, or they will be green almost all of the time, and a more pale green every day. Also, it is possible for a biofilm to build up on the water surface in the drop checker, which will interfere with the gas transport across that boundary - another reason to clean it and replace the solution every week.

I don't replace mine nearly that often, but I also don't pay any attention to the drop checker unless I am doing something different, like making a change in the way I introduce CO2, or changing the CO2 line in some way, or just trying something different. Once I know the level of CO2 is about right, I just leave the bubble rate alone, and ignore it, other than checking to be sure the CO2 tank isn't running low.
 
F

fishface

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mine was doing that as well even though co2 went out when the lights went out. i started running an air pump at night and in the mornings it was definitely blue so i think it's just not off gassing throughout the night.
 

ccLansman

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Jan 22, 2008
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thanks guys, i believe that can be a problem for tanks at night since plants need good o2 for energy production. Im going to add a connector and inject o2 into my reactor at night.
 

rodrigaj

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Aug 16, 2008
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VaughnH;32820 said:
You have to replace the solution in the drop checker about every week or two, or they will be green almost all of the time, and a more pale green every day. Also, it is possible for a biofilm to build up on the water surface in the drop checker, which will interfere with the gas transport across that boundary - another reason to clean it and replace the solution every week.
QUOTE]

I agree with the biofilm on the water surface, but know of no chemical reason for either the 4kh solution or the BTB indicator to change chemical characteristics.
 

rodrigaj

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Aug 16, 2008
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SuperColey1;32850 said:
Over the space of a few weeks air will carry contaminants into the water and once accumulated then they can affect the result.

AC

What contaminants in the air can change the 4KH solution or the BTB solution?
 

SuperColey1

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Feb 17, 2007
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Not a scientist so I can't tell you exact answers here but the proof is in the pudding.

Put 1 drop checker and leave it there without changing
Put a second drop checker in next to it and change it weekly

Watch the difference over weeks. something is changing to make the results different!!!!

I don't need to know the science to see the different reactions colourwise between fresh solution and 'old' solution.

AC
 

ccLansman

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Jan 22, 2008
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I have to agree, a film appears and the solution looses some of its color. Also i found a parcipitate forming on the inside of the bell and i cant seem to remove it. Anyone else had this? and if so how did you remove it? I tried boling water and dish soap to no avail.
 

guy tillmans

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Jul 29, 2008
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Add o2 at night?? If you have had a good photo period you have plenty of oxygen in your tank. Why should you add more o2 and and loose all you co2 at night!! Never heard of this statement. Do you have some information on the www about this?? If.. i would like to read about it.
 

ccLansman

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Jan 22, 2008
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Well i dont have any WWW. about it but my understanding was, due to the high levels of co2 being injected relative to the amount being used there would be an excess at lights off. Excess co2 should = less o2, so lights go out, plants start using what little o2 is left and we have a problem. I may be off in right field but i think this make sense. Ill let the gurus figure it out ;)
 

SuperColey1

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Feb 17, 2007
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I don't add O2 at night!!! I add O2 day and night. Keep the water surface rippling nicely drawing O in and then up the injection slightly to compensate for the extra gassing off.

AC
 

ccLansman

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Jan 22, 2008
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How are your plants doing with the o2 being on all the time? and how much did you have to up the co2 to compensate supercoley1?
 

SuperColey1

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Feb 17, 2007
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They seem to be doing OK ;)
angled.jpg


Having surface turbulence 'seems' to have several benefits but of course they may be due to something else:
-Stops the surface scum accumulating
-Improves water clarity
-Helps with the current or so it looks
-Keeps my bladder empty (rippling water sound :))

My Co2 was on 2-3bps pre surface turbulence (a long long time ago) and is currently 3-4bps

AC
 

rodrigaj

Junior Poster
Aug 16, 2008
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SuperColey1;32855 said:
Not a scientist so I can't tell you exact answers here but the proof is in the pudding.

Put 1 drop checker and leave it there without changing
Put a second drop checker in next to it and change it weekly

Watch the difference over weeks. something is changing to make the results different!!!!

I don't need to know the science to see the different reactions colourwise between fresh solution and 'old' solution.

AC

In a closed system such as a drop checker what you are describing is the equilibrium state between between the bicarbonate ion and the CO2. There is no need to change it weekly.

In fact, if you just took it out of the tank, inverted it to let the air in, reinserted the drop checker without emptying or refilling it, you would observe the same thing.
 

imeridian

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Jan 19, 2007
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It has always been my understanding that the reason for periodically changing the indicator solution was the long-term exposure to light degrading the color intensity of the bromothymol blue.
 

SuperColey1

Guru Class Expert
Feb 17, 2007
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rodrigaj, not being a scientist I will try it out (I use 2 drop checkers in my tank) and see if it works. Would be great not having to do anything and let them get their air at every 50% water change :)

I only change every 3 or so weeks anyway. I have never suggested weekly but do know it is suggested at 2-3 weeks.

I will update the thread weekly after water changes (saturday mornings)

AC