# is too much co2 bad?



## Roediger (23 Jun 2018)

hello everyone. just as the title description says is too much co2 bad?


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## Zeus. (24 Jun 2018)

To livestock yes OFC, but to the plants No, but steady [CO2] levels during photoperiod are best for plants.


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## Roediger (25 Jun 2018)

Thanks Zeus. reason I ask is because I increased co2. and started to see some GSA and I dose IE so it cant be Nitrate. so i thought  O2 was low. I have A bunch of plants so idk how fast O2 will drop. i have 6bps on a  29 gal.  I even went ahead and turned off a 32 w light lumens of 2000 and run with 2 lights to see  improvements.


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## Edvet (25 Jun 2018)

CO2 doesnt influence O2, both can be in the column.


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## Roediger (25 Jun 2018)

Edvet said:


> CO2 doesnt influence O2, both can be in the column.


So by me having some surface movement, it pumps fresh o2 into the tank correct?


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## Finn (26 Jun 2018)

An increase in CO2 can increase the rate of nutrient uptake so I wouldn't rule out a deficiency somewhere, particularly if you've got a lot of plant mass in the tank. Try just doubling your EI dosage and see if that helps. If it does, you can gradually bring it down until you run into problems to find the level that suits your tanks needs.

Also in regards to surface movement, it very much depends on your individual tank. By creating surface agitation all you're doing is simply increasing the rate of diffusion by creating a larger surface area. This doesn't necessarily increase the oxygen levels at all and in fact if your tank is thriving you're very likely driving oxygen created by your plants out of the water (and definitely driving CO2 out of the water to boot). This means that surface agitation for oxygenation is generally more useful for unplanted tanks, particularly ones that are kept on the warm side where dissolved oxygen is less available. There are some that advise increasing agitation when lights are off (in particular, ADA), however I think it's completely optional and depends heavily on stocking level.


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## Edvet (26 Jun 2018)

Roediger said:


> surface movement,


Surface movement drives CO2 out, it wil also increase O2, but in a lesser way compared to a tank full of plants growing healthy and using CO2 to increase their metabolism.
In general in a CO2 tank surface movement will decrease CO2 levels, but can be overcome by an ample CO2 dose given. When CO2 is stopped (just before lights out) the CO2 will decrease faster, helping the fish when the plants start releasing CO2 and using O2 ( their night time metabolism). This last effect can also be realised with an airstone which starts when the CO2 shuts of.


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## Roediger (27 Jun 2018)

Hmm i did read something about tom barr saying light drives co2. which drives nute uptake


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## Edvet (27 Jun 2018)

True as in high light needs high CO2 thus increasing metabolism and nutrient uptake.


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## Roediger (28 Jun 2018)

in my 10 Gal, the DC is yellow by the end of the night. The plants look good though which is why I leave it alone. What i did yesterday was change my 2 x32w bulbs and placed 24w bulb to slow down the light. hope this works out for my baby tears at the bottom. looking at it dosent seem bright but taking a pic shows the plant in bright light. also going to put more nutrient. I do 10 ml  three times a week for 15ppm of nitrate and 29ppm potassium and 4ppm phosphate.


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## Barbara Turner (28 Jun 2018)

I think most the people here have the CO2 on a timer, I turn my Co2 off an hour before the lights.  It then switches back on 2 hours before my lights come on. 
From what I've read you want to keep the Co2 level stable throughout the day and night.


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## Edvet (28 Jun 2018)

Barbara Turner said:


> and night.


not
At night it can fluctuate all it wants, plants will produce it, and using surface agitation you can drive it away (and maybe add some oxygen).


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## Roediger (28 Jun 2018)

i have a 29 galwith some surface movement. i had the tank at 3bps and this DC is still dark green. in my 10 gal its yellow! but like u guys said more co2 needs more nutrient which i wasnt doing


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## Finn (28 Jun 2018)

You should perhaps aim to reach a lime green DC before your lights turn on to make sure you're giving as much CO2 as you can (25-30mg/l is a good level) without causing harm to livestock. At this point light intensity is a much more reliable means of controlling growth. Think of reaching a good CO2 level just like EI dosing - we're aiming to supply as much as we can to reduce as many potential variables for problems as possible. The reason I suggested increasing your EI dosage is because plants can become more efficient at utilising light in amenable situations by increasing the density of chlorophyll within their cells, so can start growing faster (and in turn run into deficiency problems) under the same light source if for instance CO2 availability (the most common limiting factor for growth of submersed plants) increases. However in your case, your CO2 still sounds very low and may in of itself be causing some problems. Do you have any pictures of your tank to help us?


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## Roediger (29 Jun 2018)

I believe I have found my error... last WC, I started to use GH booster to try it out. My GH is already 4 coming out of tap water. I put 1 Tbls of GH into my 29 gal. If i am not mistaken, doesn't Gh try to hold a certain lvl of ph + co2? I wasn't having a big problem until now.before plants looked like they needed more nutes, since my DC was lime green at start of light phase; this is my 1st week I haven't seen lime green at light on.  In any case I am going to increase the co2 and nutrient after this 70% WC on sunday.  see what's happening and take some readings again. here's a pic of my tank now


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## Edvet (29 Jun 2018)

Hardness doesn't influence the amount of CO2, it does influence the pH effect of CO2 (more hardness = less pH drop from the same amount of CO2), it's doesn't effect the DC effect.


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## Roediger (29 Jun 2018)

Edvet said:


> Hardness doesn't influence the amount of CO2, it does influence the pH effect of CO2 (more hardness = less pH drop from the same amount of CO2), it's doesn't effect the DC effect.


so is less ph drop a with same amount of co2 a good thing?


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## ian_m (29 Jun 2018)

Edvet said:


> Hardness doesn't influence the amount of CO2, it does influence the pH effect of CO2 (more hardness = less pH drop from the same amount of CO2), it's doesn't effect the DC effect.





Roediger said:


> so is less ph drop a with same amount of co2 a good thing?


No, both wrong (ish).

If pH value is due to carbonate hardness (which it may or may not be in your tank) then adding 30ppm CO2 into the water will drop the pH exactly 1 unit. It doesn't matter the initial pH or KH value, 30ppm Co2 will drop pH by 1 unit.

However in practice initial pre CO2 pH value can be due to other things the carbonate which can effect the pH change. This is why a drop checker is so useful as it isolated from the tank water.


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## Roediger (30 Jun 2018)

Man this is a crazy hobby. soo many things to look out for lol. I was getting gsa in front grass area where my co2 hits the glass and down. Its not my nitrate as I pour 30ml now. And o2 is good. So i lower my light , it worked for my sons tank lowering and jsa stopped


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## Oldguy (29 Aug 2018)

To some extent it depends on which fish you are keeping (I assume plants with fish). Some fish have a ventilation system driven by oxygen requirements others like us have a system which is driven by the need to expel CO2.


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