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Ph profile, co2 and 0kh

plantnoobdude

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uk
Hi, in my high tech 60p I maintain soft water with 0kh and also inject co2.

Though 1.0ph drop is generally regarded as optimal and safe for live stock, does this still apply for tanks with no kh? I recently checked my tank pH and degas pH.

24h Degas sample is 6.65-6.7
Tank values stay from
5.2-5.3 throughout the day so far.
This means I have a ph drop of 1.4!!!

I was wondering, since I don’t have any buffer, is it possible I have less co2 in terms of ppm in the water, compared to say a tank with a kh of 4 with the same pH drop?

While my stock seem completely happy, I am a bit on edge.

Thanks!
 
I use to run my 500l tank with a 1.4pH drop. But I wouldn't recommended it as there is a fine line between fish fine and opps
Lets assume the pH meters reading is correct, what colour is your DC m8 - mine was nearly clear at times
 
I use to run my 500l tank with a 1.4pH drop. But I wouldn't recommended it as there is a fine line between fish fine and opps
Lets assume the pH meters reading is correct, what colour is your DC m8 - mine was nearly clear at times
What was the kh of the tank? My fish seem quite at home and readily accept food and engage in regular behaviours through out the photoperiod.
CC321B61-7DBD-40B7-A632-F23206101737.jpeg

Here is the dc colour, not yellow. 7 hours into photo period.
Lets assume the pH meters reading is correct,
it is a Hanna ph meter. That has been calibrated and stays within 0.03-0.04 pH of calibration solutions.
 
Here is the general layout of the tank, co2 is provided via an inline diffuser.
061C1176-003D-40EA-B89E-EEF9E9FA8D33.jpeg
 
I would trust the DC colour change as that is independent of kH and pH reading issues.
I think there also may be issues getting a correct pH reading when the kH is zero. I am not a chemist, but water can be tricky at times.
 
Though 1.0ph drop is generally regarded as optimal and safe for live stock, does this still apply for tanks with no kh?

Lets assume the pH meters reading is correct, what colour is your DC m8 - mine was nearly clear at times
I reckon with low kh the ph drop is irrelevant, although I agree for safety reasons its always wise to go with a 1 point drop.
My degassed water sits at 7.3, tank water never goes above 7. When the lights come on Co2 drops ph to 6.1, so a 1.2 drop. DC goes from @plantnoobdude green before Co2 comes on to a lime green/yellow at 6.1.

I'm paranoid about the dc colour and fish health, however I had a fault with solenoid timer a few weeks ago and Co2 stayed on all night, ph dropped to 5.8 and dc went yellow/clear, fish were completely fine, that's a 1.5 ph drop from degassed, assuming ph meter is correct.

What do we learn from this... low kh water behavior is difficult to predict.
 
Tank values stay from
5.2-5.3 throughout the day so far.

Hi @plantnoobdude

Your pH is very low. Nitrifying bacteria may struggle at such a low pH. I can't determine what livestock you have in the tank. Please clarify. I have a couple of other observations...

Although your DC is green, it's a rather odd green. And the entrance to your DC seems to be partially blocked by 'froth', particles and bubbles. This may be affecting the DC colour.

Finally, your filter inlet seems to be partially blocked by plant fragments. This may be interfering with water flow throughout the tank.

Oh, one more question - what is your water GH?

That'll do for now.

JPC
 
Hi @plantnoobdude

Your pH is very low. Nitrifying bacteria may struggle at such a low pH. I can't determine what livestock you have in the tank. Please clarify. I have a couple of other observations...

Although your DC is green, it's a rather odd green. And the entrance to your DC seems to be partially blocked by 'froth', particles and bubbles. This may be affecting the DC colour.

Finally, your filter inlet seems to be partially blocked by plant fragments. This may be interfering with water flow throughout the tank.

Oh, one more question - what is your water GH?

That'll do for now.

JPC
1. Indeed it is quite Low, though I doubt it is a problem. Stock is ember tetra and a honey gourami.

2. I have cleaned the dc and added a fresh batch of 4dkh water and bromothymol blue. Will report back in a few days.

3. I doubt it, the flow is very strong around the tank and no dead spots can be seen.

4. My gh is about 4 though I have had it as Low as 1.5 gh.
 
I would trust the DC colour change as that is independent of kH and pH reading issues.
I think there also may be issues getting a correct pH reading when the kH is zero. I am not a chemist, but water can be tricky at times.
Ok, i will use the ph meter as a view of the co2 stability for now, and the drop checker to guesstimate the concentration.
 
Though 1.0ph drop is generally regarded as optimal and safe for live stock, does this still apply for tanks with no kh?
You need much more CO2 to reach 1 degree pH drop in water with higher alkalinity. And vice versa - just a few of CO2 injected is enough for the same pH drop in water with very low alkalinity. Therefore, 1.0 pH drop is perfectly safe in your tank. You're not overdosing CO2, rather the contrary.
(In fact, 0.0000 dKH is impossible as long as there's any CO2 present because it will always partly turn into bicarbonate as long as pH value is above 4.5.)
Your pH is very low. Nitrifying bacteria may struggle at such a low pH.
Yes, but it hardly matters because ammonia (NH3) will almost 100 per cent react with water creating harmless ammonium (NH4+). Still, my experience suggests nitrifying microbes function very well at pH above 6.0, and with diminished effectiveness even at pH around 5.5.
 
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30 µS/cm. Your tank water is obviously far above this limit.
I’m guessing that would be tds of 15 if you use a tds-500 scale.
Yes, but it hardly matters because ammonia (NH3) will almost 100 per cent react with water creating harmless ammonium (NH4+). Still, my experience suggests nitrifying microbes function very well at pH above 6.0, and with diminished effectiveness even at pH around 5.5.
Yes I agree, I even fertilize with ammonium nitrate and fish see no issues, if the tank were to have say a pHof 8. I’m sure they’d be less than happy….

I don't know how your CO2 system works, an
To clarify for everyone in this thread.
The co2 system is as follows;
Co2 supermarket dual stage reg with solenoid
Camozzi needle valve
Bubble counter
Qanvee co2 inline diffuser
Co2 drop checker.
You need much more CO2 to reach 1 degree pH drop in water with higher alkalinity. And vice versa - just a few of CO2 injected is enough for the same pH drop in water with very low alkalinity. Therefore, 1.0 pH drop is perfectly safe in your tank. You're not overdosing CO2, rather the contrary.
This is comforting😊

I guess I just have the tendency to over think things…. Green drop checker, stable pH throughout photo period and happy fishies and I should stop fretting about minor details.
 
It's quite simple, though. One degree drop in pH means tenfold increase of CO2 content, but you can't take for granted that outgassed water contains 3 ppm CO2. It depends, among others, on alkalinity.:)
The general idea of measuring degassed water pH is that we assume that the CO2 concentration is in equilibrium with the atmospheric CO2 concentration, and that doesn't depend on what is in your water. There is some discussion regarding this notion that this equilibrium is close to 3ppm, but that usually is because the atmospheric concentration could change in different indoor environments.

Now from what I understand of this discussion, the core of the discrepancy is the same that popped in my CO2 topic, if the DIC equilibrium applies only to one tiny fraction of dissolved carbon, the part that forms carbonic acid, or if it applies to the entire carbon population, making it so that high pH water in equilibrium has no CO2 and only carbonates and bicarbonates.
 
While my stock seem completely happy, I am a bit on edge.
IMO no need to be on edge. Myself and many others have been running pure RO very little to no dKH tanks for years. There are loads of myths out there that still get repeated over an over. Most times it's from people who have never run a low dKH planted tank.

My fully degassed pH is 6.25 and I drop pH via CO2 injection to 4.85 on a daily basis. The readings are always very stable. My Rainbowfish show no signs of distress. However if I drop any much further they do begin to get lethargic.

That is the same at any dKH. There is always a limit where fish will show distress. It varies a bit from tank to tank but I believe that has more to do with oxygen levels. CO2 and O2 are not mutually exclusive. The higher the O2 concentration the higher the CO2 concentration can be without affecting livestock.

The people I know who run tanks in this fashion do not experience a pH crashes. They have no problem with nitrifying bacteria dying. Fish do not die from osmotic shock.

And it's not to say that pH crashes are not real. They are almost always tied to very poor maintenance. A well run clean tank at zero dKH has nothing to worry about.

Here's an article from the 2 hr Aquarist site regarding low pH tanks. My tank is pictured from several years back when I was running 1 dKH. Shortly after that article I stopped dosing any carbonates at all and not a thing changed other than the degassed pH level.

 
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IMO no need to be on edge. Myself and many others have been running pure RO very little to no dKH tanks for years. There are loads of myths out there that still get repeated over an over. Most times it's from people who have never run a low dKH tank planted tank.

My fully degassed pH is 6.25 and I drop pH via CO2 injection to 4.85 on a daily basis. The readings are always very stable. My Rainbowfish show no signs of distress. However if I drop any much further they do begin to get lethargic.

That is the same at any dKH. There is always a limit where fish will show distress. It varies a bit from tank to tank but I believe that has more to do with oxygen levels. CO2 and O2 are not mutually exclusive. The higher the O2 concentration the higher the CO2 concentration can be without affecting livestock.

The people I know who run tanks in this fashion do not experience a pH crashes. They have no problem with nitrifying bacteria dying. Fish do not die from osmotic shock.

And it's not to say that pH crashes are not real. They are almost always tied to very poor maintenance. A well run clean tank at zero dKH has nothing to worry about.

Here's an article from the 2 hr Aquarist site regarding low pH tanks. My tank is pictured from several years back when I was running 1 dKH. Shortly after that article I stopped dosing any carbonates at all and not a thing changed other than the degassed pH level.

My concern was in relation to co2 causing live stock stress, and not with ph crashes.
None the less, thank you for your advice.
 
Hi, in my high tech 60p I maintain soft water with 0kh and also inject co2.

Though 1.0ph drop is generally regarded as optimal and safe for live stock, does this still apply for tanks with no kh? I recently checked my tank pH and degas pH.

24h Degas sample is 6.65-6.7
Tank values stay from
5.2-5.3 throughout the day so far.
This means I have a ph drop of 1.4!!!

I was wondering, since I don’t have any buffer, is it possible I have less co2 in terms of ppm in the water, compared to say a tank with a kh of 4 with the same pH drop?

While my stock seem completely happy, I am a bit on edge.

Thanks!
No problems on this side of the earth.

1.4 PH drop from 6.38 down to 5 or slightly lower. 0 dKH reading. Everyone happy. Never been on edge. Drop checker yellow like urine. This said, if I had to wack a lot of plants from the tank I would slightly reduce Co2 injection to be safe.

Take a beer and relax.
 
Yes, when people using RO say 0 dKH they mean they don’t add any carbonates either intentionaly through chemicals or through the addition of heavily loaded carbonate stones like seryu stones. Now this usually doesn’t mean there isn’t any carbonate in the water. The soil will actually contain some carbonates. If the tank had actually 0dKH I think you would not be able to see any snails and your PH would actually swing, but most dKH test are not sensitive enough to detect lower amounts of carbonates hence why we say 0dKH.
 
“Note 2: The pH-KH relationship is not linear. If your tank water measures 0-1dkH, you need to target around a 1.5pH relative drop to be within reach of the 25ppm CO2 target.”

From Dennis. This little tidbit of information is quite interesting, since it links my 1.4 pH drop to my green drop checker. Quite interesting, I wonder how he arrived at this conclusion.

The article for anyone interested
 
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