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Discussion Starter · #1 ·
My tank is in the middle stages of cycling (around 5ppm of nitrites). I'm adding a UNS CO2 system soon and wondering if this will affect or stall my cycle. My water parameters are 0.5-1ppm ammonia, 5+ppm nitrite, around 80 ppm of nitrates, 7.0 PH, and 72 degrees F. I know the CO2 will bring down my PH to around 6.5 or so, will this have a negative affect on my cycle (ie. killing BB, or stalling it)?
 

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Cycling is optimized at pH of 8.4. The bacteria do better at 86 degrees Fahrenheit. KH should be between 100 and 150 ppm. Ammonia should be 2 ppm. You're good on the Ammonia at 1 ppm but your Nitrite should be under 5 ppm. 5 ppm is too high according to Doctor Tim who I don't even know is a real doctor. He probably is though. So the answer to your question is yes the 6.5 pH will slow it down some. Maybe it will slow it down a lot. But you will still get there. I have citations for this stuff but I'm feeling a bit lazy this post. You're doing well. It will work. You don't have to make any changes other than lowering the Nitrite a little.
 

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Discussion Starter · #3 ·
Awesome, I know the conditions are not optimal but at least it will cycle eventually. Also do you know of how to stop the change of ph during the co2 dosing. I'll dose the co2 at 1 bubble per second for my 7 gal tank for 8 hours a day but I heard that it can lower the pH quite a bit. Will crushed coral stop the high fluctuation of PH?
 

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Sounds like around the same PH I expect to have after co2. Thanks for the info. Also what's your temperature at? Did you experience a period of high nitrite aswell?
I hope not!!

pH is going to fluctuate no matter what kh you have.

And that's a good thing! :)

If you are adding co2 for plants you want to be at atleast a 1.0 pH drop. So for your starting 7.0ph that would put you at atleast 6.0 with co2 on.

I'm at ~5.8ph daily on my 10gal co2 tank.

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Sounds like around the same PH I expect to have after co2. Thanks for the info. Also what's your temperature at? Did you experience a period of high nitrite aswell?
My temp is usually 74-76° when I'm cycling and yes, I do have a period of high nitrites, usually only lasts a week and is handled easily by daily 50%-60% changes. Sometimes trace amounts of nitrites (just enough to slightly tint the test) of ammonia and nitrites are present for 3 weeks or so, but water changes before they hit .25 do the trick.
 

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I would not bother adjust your tank conditions (temp or pH) to optimize cycling. I'd rather be lazy and leave things as they normally would be to encourage the bacteria strains that are most competitive under your particular conditions. To be clear, I bet it probably doesn't really matter, but there's certainly no need to fret about getting things perfect. As always, the most important thing is patience.
 

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Discussion Starter · #9 ·
I would not bother adjust your tank conditions (temp or pH) to optimize cycling. I'd rather be lazy and leave things as they normally would be to encourage the bacteria strains that are most competitive under your particular conditions. To be clear, I bet it probably doesn't really matter, but there's certainly no need to fret about getting things perfect. As always, the most important thing is patience.
Okay thank you, I have no problem waiting, just wanting to make sure that it will happen sometime in the future.
 

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Awesome, I know the conditions are not optimal but at least it will cycle eventually. Also do you know of how to stop the change of ph during the co2 dosing. I'll dose the co2 at 1 bubble per second for my 7 gal tank for 8 hours a day but I heard that it can lower the pH quite a bit. Will crushed coral stop the high fluctuation of PH?
No, don't do that. Let the pH drop. Yes crushed coral would counteract it but you don't need to go there. The 80 ppm Nitrate I'm guessing means you're close to being finished on the cycling. That is unless you have been overdosing Nitrate. Is this fish in cycling or fishless cycling? If you weren't so close, I would suggest throwing the biomedia into a bucket with a heater, an airstone and a teaspoon of NaHCO3. But stay the course.
 

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Discussion Starter · #11 ·
No, don't do that. Let the pH drop. Yes crushed coral would counteract it but you don't need to go there. The 80 ppm Nitrate I'm guessing means you're close to being finished on the cycling. That is unless you have been overdosing Nitrate. Is this fish in cycling or fishless cycling? If you weren't so close, I would suggest throwing the biomedia into a bucket with a heater, an airstone and a teaspoon of NaHCO3.
Okay sounds good, and I'm doing a fishless cycle. I have some DHG, and S.Repens though. Ive added two doses of seachem flourish. One last Thursday and one the Thursday before. And yesterday I did a 40% water change. You think my cycle is almost complete despite the high nitrite?

No, don't do that. Let the pH drop. Yes crushed coral would counteract it but you don't need to go there. The 80 ppm Nitrate I'm guessing means you're close to being finished on the cycling. That is unless you have been overdosing Nitrate. Is this fish in cycling or fishless cycling? If you weren't so close, I would suggest throwing the biomedia into a bucket with a heater, an airstone and a teaspoon of NaHCO3. But stay the course.
I did a diluted nitrite test with only 1/4 tank water and got 2.0 ppm of nitrite
 

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Yes crushed coral would counteract it but you don't need to go there.
In case anyone is interested and to be clear...

crushed coral or rather the introduction of kh into the system, doesn't counteract the pH drop. It just pushes the pH drop higher due to the higher starting ph.

It does not decrease the pH drop from co2 addition.

:)

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In case anyone is interested and to be clear...

crushed coral or rather the introduction of kh into the system, doesn't counteract the pH drop. It just pushes the pH drop higher due to the higher starting ph.

It does not decrease the pH drop from co2 addition.

:)

Sent from my Pixel 3 XL using Tapatalk
You make a good point. The higher pH would grow the bacteria faster. Which is what we're after. Calcium Carbonate is weird stuff because so little of it dissolves. It buffers as it dissolves the way I understand it but the CO3 isn't as persistent as HCO3. It's not necessary to add it but it might speed things up a little.

I did a diluted nitrite test with only 1/4 tank water and got 2.0 ppm of nitrite
Wow, diluting the sample was a good Idea. Dr. Tim, if he's a real doctor, says 5 ppm Nitrite is toxic to the bacteria. I just cycled some biomedia doing 50% water changes when my Nitrite got high.
 
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The filter bacteria build up or their sustenance would not be affected by the drop in pH due to co2 injection. At least that’s what I have read from the advanced planted tank site.


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Okay sounds good, and I'm doing a fishless cycle. I have some DHG, and S.Repens though. Ive added two doses of seachem flourish. One last Thursday and one the Thursday before. And yesterday I did a 40% water change. You think my cycle is almost complete despite the high nitrite?
I think your cycle is almost complete because of the high Nitrite. Your 80 ppm Nitrate makes me wonder where that came from. Was it bacteria doing their job. I think maybe so.
 

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One thing that should be pointed out is that at lower pH levels ammonia, and nitrite, are in a less toxic form.

It seems the "sweet" point is right around 7.0. Go higher than that and the total ammonia present starts to become more and more toxic.

Completely and utterly over simplified of course :)

There's graphs online that show this relationship.

And I'll add that 80ppm seems a tad high for a new tank? But that could be me.

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UN-IONIZED AMMONIA (NH3) TABLE 25° C
pH____________________________Factor

6.5......................................................0.0018
6.6......................................................0.0022
6.7......................................................0.0028
6.8......................................................0.0035
6.9......................................................0.0044
7.0......................................................0.0055
7.1......................................................0.0070
7.2......................................................0.0088
7.3......................................................0.0110
7.4......................................................0.0138
7.5......................................................0.0173
7.6......................................................0.0217
7.7......................................................0.0272
7.8......................................................0.0329
7.9......................................................0.0424
8.0......................................................0.0528
8.1......................................................0.0655
8.2......................................................0.0711
8.3......................................................0.1000
8.4......................................................0.1227
8.5......................................................0.1497

NH3 under 0.005 is conservatively safe. Multiply your test result by the applicable factor.

at 7 pH 0.0055 x 4 ppm [NH3-N] = 0.02 ppm NH3
at 8 pH 0.0528 x 4 ppm [NH3-N] = 0.21 ppm NH3
I didn't know I could quote myself.
 

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Discussion Starter · #19 ·
One thing that should be pointed out is that at lower pH levels ammonia, and nitrite, are in a less toxic form.

It seems the "sweet" point is right around 7.0. Go higher than that and the total ammonia present starts to become more and more toxic.

Completely and utterly over simplified of course :)

There's graphs online that show this relationship.

And I'll add that 80ppm seems a tad high for a new tank? But that could be me.

Sent from my Pixel 3 XL using Tapatalk
I believe my nitrates were so high since I added some Seachem Flourish or since the Fluval Stratum leaches so much ammonia. I called my lfs that specializes in planted tanks and they reccommended a near 90% water change since the Stratum leaches so much ammonia. This brought my perameters to 0.75 Ammonia, 1.5 Nitrite, and 10-20 Nitrate. Should I just let it go and do small water changes from now on? Also should I add the C02 yet? I have everything I need. UNS Reg, Drop chekcer, Diffuser, etc. Would it be smart to cycle with CO2 since I'm already at around 7 PH. My light are on 8 hours a day and Id start CO2 an hour before they turn on and an hour before they turn off.
 

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I'd, personally, do 50% water changes daily and get my parameters under control. You can add your co2 without it being an issue (not going to effect your ammo, nitrite or nitrate any, may slow your cycle by a few days due to lower ph but nothing major). 8 hours light may be excessive to start, just be aware of that if you notice and algae issue. You might want to lower it to 5 and a half to 6 hours of these issues arise and work out your fert/ co2 balance before working back up to 8 hours. You may not encounter this issue it's just a heads up in case you do. Good luck!!
 
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