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How much ph drop with 0kh?

Tonyball

Member
Joined
11 Mar 2023
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40
Location
England
Hi all I have a quick question to ask..

I am using tropica soil substrate in my 130l tank and when I test kh it reads 0 as the liquid goes yellow with the 1st drop of test solution..

I know this is to be expected with the substrate and I also use ro water only..

What am trying to achieve is my correct ph drop to reach 30ppm co2 ...

My tank reads 7.3ph degassed when I leave a cup stand for 24 hours..

Am I right in thinking I need a 1.5ph drop to reach my target or is it even more? What's my ph drop target?

Many thanks 😊
 
What am trying to achieve is my correct ph drop to reach 30ppm co2 ...
I wouldn't focus on a ppm value as that is something that hardly anyone can measure anyway.
My tank reads 7.3ph degassed when I leave a cup stand for 24 hours..

Am I right in thinking I need a 1.5ph drop to reach my target or is it even more? What's my ph drop target?
I wouldn't advise such a big PH drop, at least when starting with CO2, which seems to be the case for you. I would go for 1PH drop, starting with 7.3PH as the initial value, so you would end up with 6.3PH.

I would highly suggest reading the following two links:
https://www.ukaps.org/forum/pages/co2-measurement-using-a-drop-checker/
https://www.ukaps.org/forum/threads/dialling-in-the-co2-injection-rate-and-co2-profiles.69460/
 
I wouldn't focus on a ppm value as that is something that hardly anyone can measure anyway.

I wouldn't advise such a big PH drop, at least when starting with CO2, which seems to be the case for you. I would go for 1PH drop, starting with 7.3PH as the initial value, so you would end up with 6.3PH.

I would highly suggest reading the following two links:
https://www.ukaps.org/forum/pages/co2-measurement-using-a-drop-checker/
https://www.ukaps.org/forum/threads/dialling-in-the-co2-injection-rate-and-co2-profiles.69460/

I have been running it this way for 11months now.. my ph is 7.3 degassed and when lights come on its 5.8ph and holds that till lights off..

Co2 comes on 4 hours before lights.

Tank sits around 6.7ph before co2 comes on it doesn't fully degass..

I read somewhere that when kh is 0 you need more of a ph drop? Around a 1.5ph drop..

So I just wanted that confirming?
 
I wouldn't focus on a ppm value as that is something that hardly anyone can measure anyway.

I wouldn't advise such a big PH drop, at least when starting with CO2, which seems to be the case for you. I would go for 1PH drop, starting with 7.3PH as the initial value, so you would end up with 6.3PH.

I would highly suggest reading the following two links:
https://www.ukaps.org/forum/pages/co2-measurement-using-a-drop-checker/
https://www.ukaps.org/forum/threads/dialling-in-the-co2-injection-rate-and-co2-profiles.69460/
 

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So he is saying here a 1.5ph drop to reach 25ppm

I am looking for 30ppm so surely I should aim for more than a 1.5ph drop? Maybe a 1.6ph drop would get me to 30ppm?
 
I have been running it this way for 11months now.. my ph is 7.3 degassed and when lights come on its 5.8ph and holds that till lights off..

Co2 comes on 4 hours before lights.

Tank sits around 6.7ph before co2 comes on it doesn't fully degass..

I read somewhere that when kh is 0 you need more of a ph drop? Around a 1.5ph drop..

So I just wanted that confirming?
When u have 0 kh you require a larger ph drop than 1ph ?
So he is saying here a 1.5ph drop to reach 25ppm
Please read this: The wrong way to read the pH/KH chart.
I am looking for 30ppm so surely I should aim for more than a 1.5ph drop? Maybe a 1.6ph drop would get me to 30ppm?
Why are you so adamant to reach 30ppm? I'm curious. Are you having issues with your plants? If you have a 1.5PH drop and your plants are not looking good then your issue is elsewhere, that's for sure. For all I know at 1.5PH drop you could already be at 30ppm or more.

As I said, no one (or nearly no one) in our hobby can actually measure CO2 ppm content precisely in our tanks. So unless you have several thousands USD to spare for a probe that measures dissolved CO2, all we can do is estimate it thanks to the KH-PH-CO2 chart (that by the way is totally skewed - see link above) and through proxies like a PH drop or the drop checker with a 4dKH solution. That 25ppm value is an estimated value and there is some variance to it. My opinion is that you are already pushing far enough with at 1.5PH drop. There are hardly many people going that low and I am one of them but I can't advise people going that low unless you are on top of your game since the consequences could be disastrous if you have fish/shrimps in the tank. If you only have plants then no big deal.
 
Hi all,
When u have 0 kh you require a larger ph drop than 1ph ?
I'm not a CO2 user, but if you are measuring the tank water then you will, theoretically, get a larger pH drop as you approach 0dKH. The reason for this is pH is less and less stable as the dKH falls toward 0.

If you use a drop checker it has a pH indicator and 4dKH solution and a known relationship between CO2 concentration and pH.

Cheers Darrel
 
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Please read this: The wrong way to read the pH/KH chart.

Why are you so adamant to reach 30ppm? I'm curious. Are you having issues with your plants? If you have a 1.5PH drop and your plants are not looking good then your issue is elsewhere, that's for sure. For all I know at 1.5PH drop you could already be at 30ppm or more.

As I said, no one (or nearly no one) in our hobby can actually measure CO2 ppm content precisely in our tanks. So unless you have several thousands USD to spare for a probe that measures dissolved CO2, all we can do is estimate it thanks to the KH-PH-CO2 chart (that by the way is totally skewed - see link above) and through proxies like a PH drop or the drop checker with a 4dKH solution. That 25ppm value is an estimated value and there is some variance to it. My opinion is that you are already pushing far enough with at 1.5PH drop. There are hardly many people going that low and I am one of them but I can't advise people going that low unless you are on top of your game since the consequences could be disastrous if you have fish/shrimps in the tank. If you only have plants then no big deal.

Yes because I thought my co2 may be low , because my temple plants are dropping around 6 leaves per day, and old growth on the dwarf hair grass is yellow, transparent..

I adjusted the surface agitation few weeks back to allow more oxygen exchange..

And I started doseing calcium and magnesium in to my ro water changes..

So I thought it mite be that the tank is getting less co2 because of the increased surface agitation..

It's ether co2 issue or cal and mag..

I am el estimative doseing .. using 2hr aquarist fertiliser.. so fertiliser shouldn't be a problem ..

Unless it's is calcium and magnesium issues..

Thanks
 
I am adding 3g magnesium and 4g calcium to every 38l of ro water on every water change... weekley
 
I adjusted the surface agitation few weeks back to allow more oxygen exchange..
Increasing surface agitation inevitably increases gaseous exchange hence more CO2 outgassing. However if you still have a 1.5PH drop after the increased surface agitation then it means you are still injecting enough CO2 and a 1.5PH drop is already high.

And I started doseing calcium and magnesium in to my ro water changes..
That's why I asked earlier why and this is probably why you had problems with your plants. When using RO you definitely NEED to remineralize since RO water is totally (or almost) deprived of any minerals.

It's ether co2 issue or cal and mag..
It's not CO2 unless you have a poor water flow and CO2 distribution in your tank. How are you injecting CO2? Diffuser? reactor?

Unless it's is calcium and magnesium issues..
This is most probably your issue.

I am adding 3g magnesium and 4g calcium to every 38l of ro water on every water change... weekley
That's around ~5dGH which is fair and should cover your needs. Perhaps posting a picture of your tank could also help assess thing a bit better.
 
Are you using a drop checker as well?

I started doing co2 profiles but find a couple of drop checkers work just as well and are easier to use, just a quick look and you have a good indication of co2 levels.

The 2hr aquarist ferts contain Mg so I doubt that's your problem, but it could be Ca
 
The 2hr aquarist ferts contain Mg so I doubt that's your problem, but it could be Ca
It does contain Mg and probably enough if you sum up a whole week worth of dosing. Nonetheless it's good practice to remineralize with both Ca and Mg to have a stable supply of both during the week and IMO the OP should continue dosing Mg regardless of what is contained in APT's ferts. Dennis, and in fact most fert producers, design their ferts for tap water or water that is already remineralized.
 
This was the tank before things went down hill..
I will post a picture of how it's looks when am home..

All I changed was surface agitation slightly and i went from doseing seachem equilibrium for water changes to calcium and magnesium Powder 3g mag 4g cal for every 38l of ro water..

I have the co2 run through a inline atomizer then through a reactor which outputs on the bottom left of the tank which blows across the carpet..

2 x wave makes set to low slightly set to cause ripples across the surface then down the left side and across carpet..

There's a good circular flow from top right across the tank and then down from bottom left to the 2x filter intakes on bottom right....

Leaves on temple plants seem to turn to mush , and fall off, new growth curly edge's and small... dwarf hair grass old growth yellow, transparent, new growth slow but green..

Plants still pearling all day long..

Co2 drop checker lime green all day..
 

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Are you using a drop checker as well?

I started doing co2 profiles but find a couple of drop checkers work just as well and are easier to use, just a quick look and you have a good indication of co2 levels.

The 2hr aquarist ferts contain Mg so I doubt that's your problem, but it could be Ca
Yes it's lime green all day long set 2 inches above substrate away from co2 output..
 
It does contain Mg and probably enough if you sum up a whole week worth of dosing. Nonetheless it's good practice to remineralize with both Ca and Mg
Yeah, not saying not to dose, just it's unlikely to be a Mg issue.


Yes it's lime green all day long set 2 inches above substrate away from co2 output.
In that case I would be looking at other causes first rather than trying to add more Co2.
 
Leaves on temple plants seem to turn to mush , and fall off, new growth curly edge's and small... dwarf hair grass old growth yellow, transparent, new growth slow but green..
Definitely not a CO2 issue.
Besides, the plants you have don't need CO2 injection at all.
 
Increasing surface agitation inevitably increases gaseous exchange hence more CO2 outgassing. However if you still have a 1.5PH drop after the increased surface agitation then it means you are still injecting enough CO2 and a 1.5PH drop is already high.


That's why I asked earlier why and this is probably why you had problems with your plants. When using RO you definitely NEED to remineralize since RO water is totally (or almost) deprived of any minerals.


It's not CO2 unless you have a poor water flow and CO2 distribution in your tank. How are you injecting CO2? Diffuser? reactor?


This is most probably your issue.


That's around ~5dGH which is fair and should cover your needs. Perhaps posting a picture of your tank could also help assess thing a bit better.
This is what a find every morning and evening leaves seem to melt at the bottom of the leave and then fall off..
Is this normal for temple plants to do this tho , as it is quite over grown..

Some of the leaves have big holes that are transparent then melt away..
 

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