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Double checking full EI dosing as per calc

dw1305

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Hi all,
A take away that I have from this discussion is that it can be quite tricky to use a pH controller when KH is really low. Some of our friends with really beautifull tanks and fish are doing this, perhaps not realising the risks involved. Now we may be lucky, as a pH that goes down (rather than up) will cause the controller to switch off.
I'm <"not a CO2 user">, but if I was I definitely <"wouldn't use a pH controller">. Drop-checkers may have their disadvantages, but they don't have any moving parts, or electronics, that can go wrong.

It is the same really with fish keeping, I would <"only aim for 0dKH"> if I was keeping (and trying to breed) <"black-water fish">, for maintenance of <"soft-water fish">, somewhere below 4dKH is fine.

cheers Darrel
 

_Maq_

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Are pH controllers reliable in water with very low conductivity? (Just asking, I've never used them, I don't inject CO2.) From my experience, pH metering in low conductivity (< 25 µS/cm) is a bit tricky.
 

Yugang

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I'm <"not a CO2 user">, but if I was I definitely <"wouldn't use a pH controller">. Drop-checkers may have their disadvantages, but they don't have any moving parts, or electronics, that can go wrong.
I respectfully disagree on the pH controller, they work very well.
I now use my probe only to check my pH curve, no control, and a pH curve gives much better visibility than a drop checker.
I continue testing my CO2 spray bar, monitoring daily with my pH probe, and it proves much better than anyting I ever used before It is really fascinating to observe how long it will take for the hobby to pick it up. Probably a few years, and that is an interesting observation in itself.
 

dw1305

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Hi all,
I respectfully disagree on the pH controller, they work very well.
I now use my probe only to check my pH curve, no control, and a pH curve gives much better visibility than a drop checker.
I can see the advantage of a pH meter to measure the pH drop, it is the controller bit that worries me.

cheers Darrel
 

Yugang

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Hi all,

I can see the advantage of a pH meter to measure the pH drop, it is the controller bit that worries me.

cheers Darrel
If you add a controller (with some points of failure) to an inherently safe injector (CO2 spray bar), you have the best of both worlds.
I am not using my pH controller really as a controller currently (only to monitor) as I learn that CO2 Spray Bar brings already the benefits that I need.
 

GreggZ

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A take away that I have from this discussion is that it can be quite tricky to use a pH controller when KH is really low. Some of our friends with really beautifull tanks and fish are doing this, perhaps not realising the risks involved. Now we may be lucky, as a pH that goes down (rather than up) will cause the controller to switch off.
I'm curious what are the risks you are referring to?
 

Yugang

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I'm curious what are the risks you are referring to?
When KH gets really close to 0, the water does not longer provide the carbonate buffering capacity in relation to CO2 injection, and you get into less predictable Co2/pH relation. So the usual pH/CO2 charts do not longer apply.

I have never noticed it with my pH controller, as I always was at least at KH = 1. For your tank, I would be a little worried
 

_Maq_

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I'm curious what are the risks you are referring to?
Take nitrification. Nitrification makes water more acidic. If for any reason, par example, feeding more than usual, the volume of nitrification exceeds its normal, pH runs down. If there's sufficient buffer capacity, you hardly notice. But if not, pH may jump suddenly down.
 

dw1305

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Hi all,
From my experience, pH metering in low conductivity (< 25 µS/cm) is a bit tricky.
That would be <"one of the issues">. You can raise the conductivity of a water sample with a <"neutral salt"> (usually NaCl or KCl) and that will give you a reading a little bit more quickly. Obviously this isn't an option in the tank.

For long term usage you would really want an <"ISFET probe"> on a meter which uses a "reference field effect transistor" (REFET), rather than a silver chloride (AgCl) glass reference electrode. <"The problem with"> all non-solid state pH meters is that they are <"continually losing potassium ions (K+) to the tank water">.
If you add a controller (with some points of failure) to an inherently safe injector (CO2 spray bar), you have the best of both worlds.
Point taken, it would be more where the pH controller was a single point of failure and adjusted the CO2 level without <"belt and braces">.

cheers Darrel
 

GreggZ

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I have never noticed it with my pH controller, as I always was at least at KH = 1. For your tank, I would be a little worried
I understand your concern but I am not worried. Not even a little.

There are many things affecting pH and conductivity in our tanks. "Pure" water only exists in a lab.

As to my tank, I can only tell you what you I have observed after years of running RO water no carbonates added. Degassed pH is very stable, almost always exactly at 6.25. I drop pH to 4.85 daily via CO2 injection. Any more and the fish begin to show signs of stress.

I've tested this too many times to count over the years. It's always the same. Very stable degassed pH and very stable pH drop. And it's not just me, it's the same for many others I know that are running tanks similar to mine.

As to pH controllers, I know they are controversial and there are strong arguments on both sides. Some here have said they are dangerous, but I use them because of the safety they provide. With a tank full of mature hard to replace, expensive Rainbowfish I look at my controller as a fail safe. If anything were to happen to other parts of the system the controller turns off the CO2 at my set point. Gives me pieced of mind.

I also like being able to adjust pH drop in small increments. If I want to see the effect of dropping/raising pH by 0.05 more/less I can just dial that in. Then set and forget and no worries. If you talk to people who have pH controllers in general they wouldn't be without them.

The only caveat is if your dKH is not stable. If so you are better off fine turning flow rate with a flow meter or very good needle valve.
 

Wookii

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If anything were to happen to other parts of the system the controller turns off the CO2 at my set point. Gives me pieced of mind.

What failsafes do you have in the other direction Gregg - for example if the pH probe fails and returns a higher pH than actually occurring, causing too much CO2 to be pumped into the tank?

I think that’s the scenario most folks fear when relying on a pH control to determine CO2 delivery, so if you have a way to mitigate that, it would be good to know?
 

GreggZ

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What failsafes do you have in the other direction Gregg - for example if the pH probe fails and returns a higher pH than actually occurring, causing too much CO2 to be pumped into the tank?

I think that’s the scenario most folks fear when relying on a pH control to determine CO2 delivery, so if you have a way to mitigate that, it would be good to know?
Good question. I buy good quality equipment and calibrate it frequently. I've been using an American Pinpoint Marine unit for many, many years now. The probes eventually do need to be replaced but I usually get about three years out of them. I calibrate once a month and rarely is it off my more than 0.03.

I also use a flow meter to keep my flow rate just slightly higher than the controller needs to keep my pH at my target. So if there were a failure it would be less of a disaster. But that has never happened.

In general I would be more worried about adverse changes in things like surface agitation and needle valve drift than a good pH controller. Even changes in plant mass and light levels can change demand for CO2. For me safety of my fish is not the only reason I use one. I also like to keep my pH drop at an optimized level regardless of other changes in the tank. It makes every other thing easier.
 

Yugang

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What failsafes do you have in the other direction Gregg - for example if the pH probe fails and returns a higher pH than actually occurring, causing too much CO2 to be pumped into the tank?

I think that’s the scenario most folks fear when relying on a pH control to determine CO2 delivery, so if you have a way to mitigate that, it would be good to know?
Some day in the future people will realise that a CO2 spray bar is inherently safe, it will overflow excess CO2 in emergency situation, and when used as the injector for a pH controller will mitigate any risk of that pH controller failing :)
 
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GreggZ

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Some day in the future people will realise that a CO2 spray bar is inherently safe, it will overflow excess CO2 in emergency situation, and when used as the injector for a pH controller will mitigate any risk of that pH controller failing :)
What is a "CO2 spray bar"??
 

kschyff

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@GreggZ thank you very much for the detail about your pH readings. I just read the article about tanks with low pH values (2HrAquarist) and I now think I may know what may have gone wrong way back when I started (and eventually stopped) using EI. Initially my CO2 never reached a point where it the pH was below 6.4 and I suspect that my micros may not have been used optimally as I am using CSM+B, where the Iron chelate works optimally below or around a pH of 6. Is my reading around this correct?

Additionally, I always assumed that if my drop checker was slightly yellow my plants would suffer tremendously. After reading the above article this is clearly not necessarily the case. In short, thanks for all the insight.
 

GreggZ

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@GreggZ thank you very much for the detail about your pH readings. I just read the article about tanks with low pH values (2HrAquarist) and I now think I may know what may have gone wrong way back when I started (and eventually stopped) using EI. Initially my CO2 never reached a point where it the pH was below 6.4 and I suspect that my micros may not have been used optimally as I am using CSM+B, where the Iron chelate works optimally below or around a pH of 6. Is my reading around this correct?

Additionally, I always assumed that if my drop checker was slightly yellow my plants would suffer tremendously. After reading the above article this is clearly not necessarily the case. In short, thanks for all the insight.
Yes CSM+B uses EDTA and is better for very low pH tanks. DTPA is a better choice when pH is higher. Now was that your problem? Who knows?

A planted tank has a lot of moving parts and the first thing folks tend to blame is fertilization. Many times issues are not tied to fert dosing at all. In fact a well run tank can get by on a pretty wide range of dosing.

As to drop checkers if I used one it would be pretty much pure yellow. Remember a drop checker is nothing but a liquid pH test and liquid pH tests in general are not very accurate. Of course much depends on ones ambitions in the hobby. The more light you provide and the more difficult plants you choose dialing in CO2 becomes more important.
 

Hanuman

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Good question. TBH I cant remember ATM 😬:oops:, I've even ask @Hanuman if he can remember
I think? Clive's suggestion of 3 ~ 4kh was once mentioned by him in regards to stability when injecting and monitoring Co2 (ph readings) I could of course be completely wrong on this.
Truth is and Clive would definitely say take no notice of kh, work with what you have, do whatever is the easiest, the plants won't care.
Also as Greggz points out, there are lots of beautiful tanks out there that run 0 ~ 1 KH.
I suspect that it’s a hang over from the now debunked belief that low KH could lead to pH crashes.
Since we are in a new era, we decided to removed the dKH values from the pre-set EI regimes in the latest update.
 

kschyff

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Apologies for resurrecting this thread again, but for some reason I can't get hold of the CSM+B micros anymore. I will have to order from abroad or come up with an alternative. I can get the GLA Micromix (EDTA 42%+DTPA 14%) in the US. I am reluctant as I can't see on rotalabutterfly where I would select this as my micro mixture. Any suggestions that might not require so much expense?
 

Zeus.

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Apologies for resurrecting this thread again, but for some reason I can't get hold of the CSM+B micros anymore. I will have to order from abroad or come up with an alternative. I can get the GLA Micromix (EDTA 42%+DTPA 14%) in the US. I am reluctant as I can't see on rotalabutterfly where I would select this as my micro mixture. Any suggestions that might not require so much expense?
Just choose 7% Fe and your done done
1656609278842.png

Some of the EDTA and DTPA will be other elements also
 
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