# Not reaching co2 requirement



## nigel bentley (24 Feb 2020)

Hi, I have a Jbl M502 Co kit. I have a problem getting the co2 checker up to 20mg required. The tank is 450litre, and the co2 test is the other end of tank from diffuser. I have replaced the diffuser with a standard glass diffuser. Absolutely no Water turbulence. I operate to Eheim 2217 with spray bars opposite end. One points down at 45 degrees, the other horizontally. My bubble counter is around 5 per second which seems a lot, operating pressure set at 2 bar. Can anyone give me any pointers please. Thanks so much Nigel


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## Zeus. (24 Feb 2020)

you will need more than 5BPS

Here my injection rate for 500l



it will probably take about 3hrs to get a 1.0pH drop on tank of 450l unless you go down the duel injection route


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## nigel bentley (24 Feb 2020)

Hi Zeus, I will increase the bps gradually and try this cheers. The co2 starts 4 hours before lights come on, I may try making it 5 hours. One point of note,the fish seem to be gasping for air at end of co2 period.. After this air pump does on for the night. Also, will try dropping tank temperature from 24.8 degs to around 22 deg Thanks  Nigel


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## foxfish (24 Feb 2020)

It is an art in its self to get  the CO2 on song!
There is not doubt in my mind that CO2 should be setup without fish in the tank, you will have to be extra careful!

How are you measuring the CO2 content, have you done a PH profile?

The bubble count can only ever be a guide but as Zeus points out you will probably have to double you rate.

There are quite a few things that can influence how effective your CO2 system will work... the amount you inject, the way it is distributed, how long it stays in suspension, the amount of surface movement, how much plant mass you have and much more... some folk just hit it right straight away... some never get there!


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## nigel bentley (24 Feb 2020)

Hi, the ph reads around 7.8 in the morning and at the end of the light period around 6.6.Maybe,I'm focusing too much on the the drop checker which is showing around 15mg.I was using a 500g bottle and this was lasting around 14 to 16 days. Have upgraded to a 2kg bottle now. Agreed, co2 should have been sorted before introducing fish. I was trying to cycle tank though with a few hardy barbs. Thanks for your help. Nigel


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## nigel bentley (25 Feb 2020)

Hi, Just a little update,iam really stuck and tempted to give up on the co2 experiment. Came home from work after increasing co2. Co2 drop checker now showing 20 mg per litre but fish are struggling so much, I have turned off co2 and started adding oxygen. PH this morning was 7.9 now is 6.6..Thinking maybe drop checker is either faulty or Iam colour blind. I will post a photo of this soon. I would be grateful for any advice. Thanks Nigel


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## nigel bentley (25 Feb 2020)




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## nigel bentley (25 Feb 2020)

The four people in our house are differing in views. 2 of us see it@20mg, the other two see50 mg. If it is 50 mg whence the problem. Also, I think 1.3 is quite a big pH drop over 8 hours??? Sorry for all the long winded posts but I could do with some help please


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## Jayefc1 (25 Feb 2020)

Looks on the higher side to me cant really tell with the picture its defo not lime green though


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## Zeus. (25 Feb 2020)

and read D Wong on CO2 - its not just the drop it needs to be stable from lights on till CO2 off 



ceg4048 said:


> A. We understand that Rubisco's job is to capture CO2 molecules and to deliver the molecules to the Calvin Cycle reaction centers. We know that Rubisco is hugely expensive and consumes a lot of resources to produce and to maintain. In low tech tanks, where the CO2 concentration is low there is a much higher density of Rubisco in the leaf because you need more of the protein to capture the small amounts of CO2. In gas injected tanks, the Rubisco density in the leaf is lower.
> 
> B. We also know that during Calvin Cycle, the fixing of Carbon involves some intermediate carbohydrate products until the final product is a type of glucose.
> 
> So, for item A. we know that when the plant senses that high concentrations of CO2 is available, it responds by reducing the production of expensive Rubisco. When it senses a lower CO2 concentration it must increase Rubisco production, however because this protein is so complicated and heavy, the increased production requires 2-3 weeks in order to change the density in the leaf to match the new gas concentration level. So it is much easier to reduce production than it is to increase production. When increasing gas injection therefore, it hardly takes any time to see an improvement in health. When lowering the concentration, the plant will suffer because it must now ramp up Rubisco production to account for the loss of CO2 availability


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## nigel bentley (25 Feb 2020)

Thanks Zeus, think I picked up a few tips ther. Not only did I increase co2 yesterday, I lowered spray bars maybe reducing gaseous exchange. I will now raise spray bars and have another go. Luckily, the fish have all recovered. 
. Thanks for the video link. All the best Nigel


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## Zeus. (25 Feb 2020)

Sorry I didnt post the links the other day but was busy


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## nigel bentley (25 Feb 2020)

No worries, thanks again mate. I ve been keeping fish for 30 odd years now but new to aquascaping. Totally new league to me, but great to learn from you guys.


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## jaypeecee (26 Feb 2020)

nigel bentley said:


> Hi, I have a Jbl M502 Co kit. I have a problem getting the co2 checker up to 20mg required. The tank is 450litre, and the co2 test is the other end of tank from diffuser. I have replaced the diffuser with a standard glass diffuser. Absolutely no Water turbulence. I operate to Eheim 2217 with spray bars opposite end. One points down at 45 degrees, the other horizontally. My bubble counter is around 5 per second which seems a lot, operating pressure set at 2 bar. Can anyone give me any pointers please. Thanks so much Nigel



Hi @nigel bentley 

I have a few observations/questions:

1 Please indicate which "standard glass diffuser" you are now using.

2 What are you using to distribute the CO2 around the tank? Are you relying entirely on the Eheim 2217 and spray bars?

3 Can you see bubbles of CO2 being 'blown' around the whole of the tank?

4 I appear to have the same JBL regulator as you with operating/working pressure set at 2 bar.

5 I don't support the recommended 1.0 pH drop as detailed in https://www.ukaps.org/forum/threads/why-advise-a-1ph-drop.58798/.

6 It's interesting that your JBL DC colour chart shows 20 mg/l CO2 as optimum. If you look around here on UKAPS and elsewhere, I think the optimum is generally reckoned to be 30 mg/l.

7 You have demonstrated why I am uncomfortable with drop checkers. I use an electronic version of the DC principle. It's my solution to the colour-matching problem that you have highlighted. JBL have a test kit that you could consider. I have used the predecessor to this one:

https://www.jbl.de/en/products/detail/8691/jbl-proaquatest-co2-direct

It's a bit of a faff to use but it may be worth a try.

8 There are two ways of dealing with waste in the form of ammonia in the tank. One is to let the plants consume the ammonia, the other is to set up a nitrifying microorganism colony in the Eheim 2217. But, please don't use fish for this purpose. If you decide to opt for the fishless cycle method, I have some experience of that. If you choose to let the plants do this, then perhaps @dw1305 could advise you.

There ya go!

JPC


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## Wookii (26 Feb 2020)

For what its worth, adding my 2p.

I only target a pH 0.8 drop, if I push it to a full pH 1.0 drop my Amano shrimp go nuts around the top of the tank, and I lose cherry shrimp. My theory is that my atmospheric CO2 levels are higher than that used to determine the original pH 1.0 drop recommendations (Nottingham/Midlands is known for poorer air quality than a lot of the UK) - as mentioned in the thread that @jaypeecee linked to. The case might be the same for you being in Greater London, so I think your pH 1.2/1.3 drop is far too much.

I have the same drop checker as you, and it's a good unit - far easier to read than the clear glass ones. That said it's hard to tell from your photo as its too dark, but it looks like you're on the upper end. A full tank shot would also be beneficial.. It would be good to see a fresh photo well lit up so its easier to see the drop checker colour. This is mine at my 0.8 Ph drop:






Also bear in mind that the drop checker is only telling you the CO2 levels at that position in the tank. It could well be, if your distribution isn't that great, that the levels are much higher elsewhere in the tank. I personally use two of these drop checkers - one where I estimate the CO2 is likely to be at its lowest (the end of the in tank circulation) and one at the opposite end of the tank where I expect 'average' levels to be - in direct flow of the CO2 source. If distribution is optimised, they should be the same colour. In your case you could try moving the drop checker elsewhere in the tank, to see if the CO2 levels are different (bearing in mind it can take 2 hours to change colour).

Given you are using spray bars, I think you should really look to add an inline diffuser or better still an external reactor (they are easy enough to DIY). That will help you to achieve better and more even distribution of CO2 as the output of both of your spray bars will all have the same CO2 saturation - I think the single point source in-tank diffusers only really work well when using a single point source filter outlet that is responsible for the entire tank distribution.

Finally you mention minimising surface agitation - I think this is a mistake, as you want to tray and maximise dissolved oxygen levels. Yes you may chew through more CO2 as a result, but it will help your livestock, especially if you have a deep tank - I also believe higher DO levels help minimise algae.


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## nigel bentley (26 Feb 2020)

Hi Jaypeecee  and Wookii,,, iam using a Jbl Pro flora taifun ceramic diffuser. I am using just the spray bars to distribute co2. I can see co2 bubbles at across about40% of tank. Could be the explanation! The colour of my drop checker is definitely not the same colour as yours. Also the plants are doing a little better on the diffuser side. I will post a short video in a moment, with the spray bars off to show co2 bubbles etc. Thank you both for your thoughts   Nigel ps sorry can't post video at moment


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## Zeus. (26 Feb 2020)

Wookii said:


> I only target a pH 0.8 drop, if I push it to a full pH 1.0 drop my Amano shrimp go nuts around the top of the tank, and I lose cherry shrimp. My theory is that my atmospheric CO2 levels are higher than that used to determine the original pH 1.0 drop recommendations (Nottingham/Midlands is known for poorer air quality than a lot of the UK) - as mentioned in the thread that @jaypeecee linked to. The case might be the same for you being in Greater London, so I think your pH 1.2/1.3 drop is far too much.
> 
> I have the same drop checker as you, and it's a good unit - far easier to read than the clear glass ones. That said it's hard to tell from your photo as its too dark, but it looks like you're on the upper end. A full tank shot would also be beneficial.. It would be good to see a fresh photo well lit up so its easier to see the drop checker colour. This is mine at my 0.8 Ph drop:



Using same DC here and I would question what your taking the pH with, as with that change in DC colour my pH is over 1.0 pH. pH probes/pens are not accurate and I only trust them to see if the pH is stable i.e. the reading they give is irrelevant, so if it says 6.5pH when lights come on then stays at 6.5pH for the rest of the CO2 period and the DC turns green or green/yellowish or Yellow then the pH of the tanks water has been stable from lights on till CO2 off and the change in the colour of the DC gives an indication of the [CO2], if the tanks inmates are fine all is good. I trust the DC as the way its works is simple but pH probes/pens are tricky little devils 

Is the [CO2] the same all over the tank well thats done to having good flow/turnover.

I have had my DC going nearly clear at times and my Amanos and RCS was fine as long as the surface agitation was good, but have also lost RCS when the DC was yellow green when surface agitation was poor


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## Wookii (26 Feb 2020)

Zeus. said:


> Using same DC here and I would question what your taking the pH with, as with that change in DC colour my pH is over 1.0 pH. pH probes/pens are not accurate and I only trust them to see if the pH is stable i.e. the reading they give is irrelevant, so if it says 6.5pH when lights come on then stays at 6.5pH for the rest of the CO2 period and the DC turns green or green/yellowish or Yellow then the pH of the tanks water has been stable from lights on till CO2 off and the change in the colour of the DC gives an indication of the [CO2], if the tanks inmates are fine all is good. I trust the DC as the way its works is simple but pH probes/pens are tricky little devils
> 
> Is the [CO2] the same all over the tank well thats done to having good flow/turnover.
> 
> I have had my DC going nearly clear at times and my Amanos and RCS was fine as long as the surface agitation was good, but have also lost RCS when the DC was yellow green when surface agitation was poor



My Ph probe is a Hanna Halo - it appears to be very accurate as far as I can tell. I calibrate every two weeks using dual Hanna calibration solutions, and drift so far has been less than pH 0.05 each time.

The probe is certainly far more accurate than comparing drop checker colours.


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## Wookii (27 Feb 2020)

Zeus. said:


> Using same DC here and I would question what your taking the pH with, as with that change in DC colour my pH is over 1.0 pH. pH probes/pens are not accurate and I only trust them to see if the pH is stable i.e. the reading they give is irrelevant, so if it says 6.5pH when lights come on then stays at 6.5pH for the rest of the CO2 period and the DC turns green or green/yellowish or Yellow then the pH of the tanks water has been stable from lights on till CO2 off and the change in the colour of the DC gives an indication of the [CO2], if the tanks inmates are fine all is good. I trust the DC as the way its works is simple but pH probes/pens are tricky little devils
> 
> Is the [CO2] the same all over the tank well thats done to having good flow/turnover.
> 
> I have had my DC going nearly clear at times and my Amanos and RCS was fine as long as the surface agitation was good, but have also lost RCS when the DC was yellow green when surface agitation was poor



Sorry my message above posted before I’d finish - must have miss hit submit.

To be fair that drop checker is at the front of my tank opposite the filter outlet, whereas the probe is at the rear of the tank, so there could conceivably be a 0.2 or so pH difference between the two, though the rear drop checker colour does look very close.

Can you post a picture of your drop checker at your pH 1.0 drop? Is your pH probe next to your drop checker when you’re making the comparison?


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## nigel bentley (27 Feb 2020)

Good morning guys, A little update, I have just ordered an Eheim compact 2100 pump which is coming tomorrow.  Along with the 2217 spray bars, which I now believe are insufficient on their own, the water turnover will be 9 times the tank size. With just the spray bars it was only just over four.

Also considering moving diffuser onto back wall on right hand side and putting pump outlet pipe on right hand side wall. Both spray bars are now raised causing surface agitation which I hope will help with the gaseous exchange.

I have increased co2 time to 12 hours coming on 6 hours before lights on and going off 1 hour before light off. Because the tank is 450 Litres and quite deep, I hope the increased time will help co2 to reach higher level

After 8 weeks (weeks 5,6,7 & with fish), I now believe tank s cycled.
Reading are Ammonia 0
Nitrite 0
Nitrate 20ppm

I will post an update in a few days once the pump has been running.

As always, thanks so much for all the   kind help

Cheers Nigel


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## foxfish (27 Feb 2020)

Good luck Nigel, getting a good balance is not easy but once you have grasped how it all works it will seem much easier to understand .
As much as folk try to help and pass on their  own experiences, at the end of the day every tank is going to require its own ideal settings and there is only one way find that out.
Obviously it would be far better if you did not have live stock but if you just go slowly with small adjustments you (or your fish) should be fine.


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## Witcher (27 Feb 2020)

@nigel bentley the lower is kH of your water the easier is to set the pH to the desired level as you have less buffer in low kH water.

For example to drop ph from 7 to 6.9 you'll need only 0.4pm of CO2 at 0.5 kh, but you'll need 7.8ppm of CO2 at 10 kH.


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## nigel bentley (27 Feb 2020)

Thanks Foxfish. You are right, no 2 tanks are the same. Learning loads with new experiences, thanks a lot.


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## jaypeecee (27 Feb 2020)

Zeus. said:


> ...pH probes/pens are not accurate and I only trust them to see if the pH is stable i.e. the reading they give is irrelevant..



There are a lot of cheapo so-called pH probes/pens now available. I wouldn't trust them as far as I could throw them. It's no different from anything else. But, the pH probes, meters, etc. from reputable manufacturers such as Hanna Instruments, Extech and Omega are some of the ones to consider. I have an Extech PH100 - it has an accuracy of +/- 0.01pH. I maintain this with calibration buffer solutions. Very expensive pH meters are required for measuring the pH of low ionic strength solutions (low TDS/conductivity) but that need has never arisen for me in the aquatics hobby.

JPC


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## Zeus. (27 Feb 2020)

Wookii said:


> Can you post a picture of your drop checker at your pH 1.0 drop? Is your pH probe next to your drop checker when you’re making the comparison?



Well my tank has been running fine for well over a year so I rarely take the pH to be honest, but it was over 1.0pH drop last i checked,  I just go of the DC colour being yellowish/green and the lack of algae



jaypeecee said:


> There are a lot of cheapo so-called pH probes/pens now available. I wouldn't trust them as far as I could throw them. It's no different from anything else. But, the pH probes, meters, etc. from reputable manufacturers such as Hanna Instruments, Extech and Omega are some of the ones to consider. I have an Extech PH100 - it has an accuracy of +/- 0.01pH. I maintain this with calibration buffer solutions. Very expensive pH meters are required for measuring the pH of low ionic strength solutions (low TDS/conductivity) but that need has never arisen for me in the aquatics hobby.
> 
> JPC



Yep I have a Hanna, but not cheap but still a PITA to calibrate


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## nigel bentley (28 Feb 2020)

I have had a break through. Dc now reading 20mg!!! Have installed pump internally on lowest setting, water turnover now 6.5 times during photo period. Fish happy, water chemistry good. Would have pump on higher setting but don't like the look of lots of turbulence. Thanks guys for your help, couldn't have done this without you! My Lfs had insisted no water movement at surface was best but I now know this not to be the case.!!


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## JoshP12 (18 Mar 2020)

nigel bentley said:


> I have had a break through. Dc now reading 20mg!!! Have installed pump internally on lowest setting, water turnover now 6.5 times during photo period. Fish happy, water chemistry good. Would have pump on higher setting but don't like the look of lots of turbulence. Thanks guys for your help, couldn't have done this without you! My Lfs had insisted no water movement at surface was best but I now know this not to be the case.!!



Woot! I was typing up a post, then re read this!  Hurrah for surface agitation.

Congrats.

Josh


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