ph/c02 discovery that dont quite understand

[jonfromscotland]

hmm,

So i had been slighty confused dialing in my c02 but now understand. .. sort of

My tap is PH:6.9 with kh:1 GH:2-3

Now my tank water has some seiru stone which packet said slightly changed water chemistry. I also use tropic aquasoil. Between these i didnt really have a baseline but when i did test near the start it seemed around 7. However, it was hard to tell as c02 was being used early on and i didnt realise you could test the water by stiring it to remove the c02.

anyways. .... i was getting algae issues and so increased it from one of these to the other below..

from start
7:00: ph6.9 / KH4 - C02 ON - (i think it used to be 7 before i increased injection to 6>8 hours. Appears effect not wore off from previous?)
8:00: ph6.6 - med green - LIGHTS ON
9:00: ph6.5 - med green
10:00 ph6.4 - med-light green
11:00 ph6.3 - lime green
12:00 ph6.3 - lime green
13:00 ph6.3 - lime green, nearly yellow
14:00 ph6.3 - lime green, nearly yellow
15:00 ph6.2 - lime green, nearly yellow - C02 OFF .....
16:00 LIGHTS OFF

June14 - about 2 months on ....
6:00: C02 on ....
8:00: ph6.3 - med-light green - LIGHTS ON
9:00: ph6.3 - light green (yellow when out of water)
10:00 ph6.2 - light green (yellow when out of water)
11:00 ph6.2 - light green (yellow when out of water)
12:00 ph6.2 - light green (yellow when out of water)
13:00 ph6.1 - light lime green (yellow when out of water)
14:00 ph6.1 - light lime green(yellow when out of water)
15:00 ph6.1 -light lime green(yellow when out of water)

*** note drop checker colour is actually not yellow ... my room lights make it look yellow. When in bathroom in natural light with white background it reverts to roughly what it is in water. Light lime green, tinge of yellow is the most i have seen.

Now i did this thinking in my head my base was like tap water ... 6.9 which i admit was kind of dumb. I may have done tests also ater big water changes perhaps which also messed up results. Anyway, today is Tue and i di di 60% change last thur

my aquarium water is PH7.6 KH4-5 GH:6-7 !!

This means the drop is pretty huge actually and that my calculation were way off. I think the fish not gasping is what gave me confidence but this brings me on to my worry. From some brief research, gasping is not the only symtom. Lathargy is too and i think perhaps my fish do become less active as the day goes on. Perhaps only reason they were not too bad is a have oase biomaster 350 with lilly pipes pointing upwards. This is probably enough to balance out the c02 with 02/' gas exchange.

Still, how do you guys judge the fish? Perhaps they are just more active early in day and wind down naturally as well?

 

[iggy2k]

Test the water when it's stopping as well instead of tidying the drop checkers see what results you get.

Sent from my SM-S918B using Tapatalk

 

[MarcusA]

I had the same experience. I was under the impression that the added CO2 entirely dissipated during the lights off period and didn’t realize how much remained through the night until I tried mixing my tank water with fresh outdoor air, whereupon I found that my ph drop was much bigger than I thought it was.

Ultimately, the experience led to me abandoning ph readings. My meter’s sensor expired a while ago and I never ordered a replacement. In my mind, the true test of maximum CO2 is livestock health. Ph readings give us a nice exact number while judging livestock health is inexact and subjective and initially time-consuming, but ultimately, livestock health is what truly determines then maximum concentration of CO2 that we can pump into our aquariums. Although I cannot claim to be a master aquascaper, my approach is to pump in enough CO2 to make the plants pearl but not so much that the fish gasp. In other words, the amount is determined by observation of the tank rather than ph readings.

 

[jonfromscotland]

I had the same experience. I was under the impression that the added CO2 entirely dissipated during the lights off period and didn’t realize how much remained through the night until I tried mixing my tank water with fresh outdoor air, whereupon I found that my ph drop was much bigger than I thought it was.

Ultimately, the experience led to me abandoning ph readings. My meter’s sensor expired a while ago and I never ordered a replacement. In my mind, the true test of maximum CO2 is livestock health. Ph readings give us a nice exact number while judging livestock health is inexact and subjective and initially time-consuming, but ultimately, livestock health is what truly determines then maximum concentration of CO2 that we can pump into our aquariums. Although I cannot claim to be a master aquascaper, my approach is to pump in enough CO2 to make the plants pearl but not so much that the fish gasp. In other words, the amount is determined by observation of the tank rather than ph readings.

This is essentially my question although i perhaps wasnt clear.

How to determine livestock health?

Fish gasping is a bit too binary for me. I read colour and lathargy can be a thing too but this can be subtle.

BTW i did have 1 fish that went up quite a lot and did gasp at surface, died. Still, others in its species (pear danio) doing fine and quite active even late in the "day". Also, it wasnt gaping constantly. Just went up perhaps 30% of the time.

 

[MarcusA]

Sorry I got off on a tangent there without answering your question lol. The truth is, I don’t have any great insight to share. I just compare my fish on a day without CO2 to a day with CO2 and ask myself if they pretty much seem the same.

 

[Zeus.]

My tap is PH:6.9 with kh:1 GH:2-3

some seiru stone

my aquarium water is PH7.6 KH4-5 GH:6-7 !!

Add CO2 injection and pH drop
the seiru stone dissolves and changes the KH/GH of tank @Wookii had same issue

 

[bazz]

Hi.
I personally would advise that there is really no need to inject such high levels of CO2 that you're fish are gasping at the surface or the drop checker is turning yellow, turn it down notch and head for the mid table. The important factor from there on is to keep the level stable throughout the photoperiod (along with all the other parameters), 30 mg/l is for people who need rapid plant growth for competitions, demanding plants or whatever reason.
This works fine for me, my fish and plants.

 

[jonfromscotland]

Add CO2 injection and pH drop
the seiru stone dissolves and changes the KH/GH of tank @Wookii had same issue

just to be clear, you are saying the c02 injection itself increases acidity which melts the stone more than normal, thus raised "real ph" more?

Thats going to make any judgement pretty hard!

 

[jonfromscotland]

Hi.
I personally would advise that there is really no need to inject such high levels of CO2 that you're fish are gasping at the surface or the drop checker is turning yellow, turn it down notch and head for the mid table. The important factor from there on is to keep the level stable throughout the photoperiod (along with all the other parameters), 30 mg/l is for people who need rapid plant growth for competitions, demanding plants or whatever reason.
This works fine for me, my fish and plants.

To be fair its never actually been yellow. Quite strong lime green at one point in my journey at end of day ....

Yeah i am pretty scared of the inconsistency as right now i am fiddling way to much. yesterday i did two minor decreases ... Below is all my readings ... Thinking i might just leave it as is. Its 11:00 am now and checker is light green, PH 6.5 ....

jul 10 - very slight decrease night before
6:00: C02 on
8:00: ph6.6
9:00: ph6.6
10:00 ph6.5
11:00 ph6.


jul 9 - very slight decrease night before
6:00: C02 on
8:00: ph6.4 - light green
turned down at 857 when discovered my PH is 7.7!
9:00: ph6.4
10:00 ph6.4
11:00 ph6.4 - lime green
12:00 -
13:30 -
14:00 -
14:44 ph6.3
15:00 ph6.3


jul 8 - slight increase night before
6:00: C02 on
8:00: ph6.6
increased slightly …….
9:00: ph6.5
10:00 ph6.4
11:00 ph6.3
12:00 ph6.3
13:30 ph6.2
14:00 ph6.2
15:00 ph6.2 - lime green/yellow/ very light lime green almost yellow

jul 7 - turned down few days ago in several steps as two fish looked pave/gasp ( colours updated and are now in water/out water/ out water in bathroom)
6:00: C02 on
8:00: ph6.6 - mid green /light green /mid green
9:00: ph6.6 - mid green /light green /mid green
10:00 ph6.5 - mid green /light green /mid green
11:00 ph6.5 - light green / lime green / light green
12:00 -
13:00 -
14:00 -
15:00 wasnt in maybe 6.4-6.5
16:00 ph6.5 - light green /lime green /light green

June14 (algae issues + decided to start 2hours early for consistency)
6:00: C02 on ....
8:00: ph6.3 - med-light green - LIGHTS ON
9:00: ph6.3 - light green (yellow when out of water)
10:00 ph6.2 - light green (yellow when out of water)
11:00 ph6.2 - light green (yellow when out of water)
12:00 ph6.2 - light green (yellow when out of water)
13:00 ph6.1 - light lime green (yellow when out of water)
14:00 ph6.1 - light lime green(yellow when out of water)
15:00 ph6.1 -light lime green(yellow when out of water)

Junes13 (original quite inconsistent settings as start only hour early)
7:00: ph6.9 / KH4 - C02 ON - (i think it used to be 7 before i increased injection to 6>8 hours. Appears effect not wore off from previous?)
8:00: ph6.6 - med green - LIGHTS ON
9:00: ph6.5 - med green
10:00 ph6.4 - med-light green
11:00 ph6.3 - lime green
12:00 ph6.3 - lime green
13:00 ph6.3 - lime green, nearly yellow
14:00 ph6.3 - lime green, nearly yellow
15:00 ph6.2 - lime green, nearly yellow - C02 OFF .....
16:00 LIGHTS OFF

 

[dw1305]

Hi all,

just to be clear, you are saying the c02 injection itself increases acidity which melts the stone more than normal, thus raised "real ph" more?

<"Yes">.

my aquarium water is PH7.6 KH4-5 GH:6-7 !!

Ultimately, the experience led to me abandoning ph readings

Just use the drop checker, it isn't effected by anything other <"than the level of dissolved CO2">.

That one. It is only the carbonate hardness of the <"4 dKH solution in the drop checker"> that matters. The base in solution (sodium bicarbonate (NaHCO3) etc.) is the <"proton acceptor">.

Because the drop checker has an air gap, the colour change of the bromothymol blue, narrow range, pH indicator is entirely dependent upon CO2 that diffuses across that air gap, and the small proportion of that CO2 that becomes carbonic acid (H2CO3). That is why you have the 2 hour lag period, it gives time for the drop checker to "catch up". I still like the <"bouncy castle analogy">.

From some brief research, gasping is not the only symptom. Lethargy is too and i think perhaps my fish do become less active as the day goes on.

turned down few days ago in several steps as two fish looked pale/gasp

There definitely are <"sub-lethal effects"> to prolonged high CO2 exposure.

turn it down notch and head for the mid table

Sound advice, personally I don't (<"and won't">) add CO2, but if I did? It would be with a dark green drop checker.

cheers Darrel

 

[Andy Pierce]

@jonfromscotland If you want to be quantitative with the drop checker, get yourself a colour-grab app and measure the H value of the drop checker colour on an HSV scale. H (hue) will do a really nice job of giving you a digital readout of how "lime-green" the checker really is.

 

[jonfromscotland]

thanks for the advice all,

My plan was always to use moderate/low c02 and be cautious but i think i got carried away/panic by algae and balance thoughts ....

I did my filter clean and 70% water change yesterday. It has only taken until today from that to take my gassed off PH from 6.9 > 7.7. I guess this stone works fast ... I wont be using it again as its an additional variable i dont need. Then again, the boost to KH may actually be welcome as my tap water 1 is perhaps more of a problem...

Anyway, my drop checker is light green at the moment with 1 hour til c02 off time. The fish are buzzing all over the place looking very natural and happy. Everything looks idealic with plants pearling and busy fishes. The pygmy cories are chasing those bubbles and foraging in that way we all love.

I think ill leave it as is with these levels. I am considering upping my liquid ferts from 7ml TNC complete water change day + mid week to some kind of daily routine but i will let it settle first.

 

[dw1305]

Hi all,

I guess this stone works fast ... I wont be using it again as its an additional variable i dont need.

It certainly is another variable. I don't think that added CO2 and limestone (CaCO3) rocks is ever a good mix in terms of the stability of water chemistry.

Then again, the boost to KH may actually be welcome as my tap water 1 is perhaps more of a problem...

Honestly soft tap water is a gift, not a burden. You can always <"harden soft water">, have a look at @Roland's <"Soft water tank">.

My 70l tank,gh5/6 ,kh1,

The fish are buzzing all over the place looking very natural and happy. Everything looks idyllic with plants pearling and busy fishes

Perfect. The tank looks good.

cheers Darrel

 

[jonfromscotland]

Hi all,

It certainly is another variable. I don't think that added CO2 and limestone (CaCO3) rocks is ever a good mix in terms of the stability of water chemistry.

Honestly soft tap water is a gift, not a burden. You can always <"harden soft water">, have a look at @Roland's <"Soft water tank">.


Perfect. The tank looks good.

cheers Darrel

Yeah i did PH test after my big big water change and the actual change in PH was only about 6.4 > 6.6. The stone then increases over maybe 24 hours but with the c02 fighting the effects i guess. Actual PH readings change is perhaps not too fast but im sure that is too simplistic. I know "c02 ph change" is very different to other PH changes and how this impacts the stress or health on the fish is probably beyond our understanding.

I do however think stability is key and I didnt help that. BTW i did research the stone and most places (including the packet) said it was quite subtle! as you can see from pics i dont have that much of it either. it would be a nightmare to remove though as its all glued and intermixed with the wood.

Anyway, my main goal is more lush growth and colours. They do look better than my pic does justice but not on same level as yours. I think my cleaning routine, c02 and light levels are solid for now so perhaps i should leave month or 2 and learn more on ferts. I am also hoping i can up the light a bit once my tank matures. Its only 50 at the substrate which is moderate and only 4/7 for my beas of a light.

 

[dw1305]

Hi all,

The stone then increases over maybe 24 hours but with the c02 fighting the effects i guess. Actual PH readings change is perhaps not too fast but im sure that is too simplistic.

That is the reason why I like the drop checker, it is only dissolved CO2 that matters <"CO2 Measurement Using A Drop Checker">.

I know c02 ph change is very different to other PH changes

Yes, it is a strange one, you really need @hax47 or @Andy Pierce for a proper explanation, but basically adding CO2 <"mimics an atmosphere richer in CO2"> and this changes the pH point of the CO2 ~ Carbonate equilibrium equation. I think this just means that you have more dissolved inorganic carbon (D(T)IC) and a greater proportion of this DIC is as CO2.

how this impacts the stress or health on the fish is probably beyond our understanding.

I'm not a CO2 user and I wasn't originally aware that adding CO2 was a <"thing">, but as soon as I found that <"aquascapers had healthy fish"> and also had a relatively rapid drop (& rise) of 1 pH unit every day, I knew that the idea that the idea that <"pH fluctuations were inevitably deadly"> to fish was wrong.

cheers Darrel

 

[Zeus.]

Think where you are going wrong is the adjusting the injection rate and still using the one/two hour before lights on for CO2 start time. You need to find the injection rate that gets a stable target pH first, then time how long it takes to reach the target pH, the time it takes is the time it takes with single CO2 injection

Dialling in the CO2 injection Rate and CO2 Profiles​

The chances that its actually 60/120mins is very very low IMO

 

[hax47]

I know "c02 ph change" is very different to other PH changes and how this impacts the stress or health on the fish is probably beyond our understanding.

Yes, it is a strange one, you really need @hax47 or @Andy Pierce for a proper explanation, but basically adding CO2 <"mimics an atmosphere richer in CO2"> and this changes the pH point of the CO2 ~ Carbonate equilibrium equation.

The difference lies in the ability of gases (CO2 among them) to cross the epithelial layer of the gills, whereas protons can not. So the low pH would not have such a huge effect as CO2. One of the main buffers in fish blood is the bicarbonate buffer and an increase in the CO2 concentration will lower the pH in fish tissues.
If I remember correctly, the normal CO2 concentration in fish blood is around 5-10 mg/l, but that can be very species- and tissue-dependent. It also depends on the fish's metabolism and physical activity. So when environmental CO2 is elevated, the in-fish CO2 will also, it can not be lower than the environmental CO2.
The fish can adapt to elevated CO2 levels to a certain point and can excrete protons into the environment through their gills (while at the same time, the gills produce bicarbonate into the blood), which is an energy-intensive process. That is probably why the enzymes required for energy production are generated more intensively in the gills when fish are exposed to high CO2 < https://www.ukaps.org/forum/threads/c02-and-fish-health.75097/post-758866 >.

 

[dw1305]

Hi all,

It also depends on the fish's metabolism and physical activity. So when environmental CO2 is elevated, the in-fish CO2 will also, it can not be lower than the environmental CO2. The fish can adapt to elevated CO2 levels to a certain point and can excrete protons into the environment through their gills (while at the same time, the gills produce bicarbonate into the blood), which is an energy-intensive process.

You can find figures for the <"Bohr"> and <"Root"> effects <"for fish"> that are used in aquaculture.

Unsurprisingly <"fish like Common Carp"> (Cyprinus carpio) are much more tolerant of high CO2 / low O2 levels than Salmonids etc. - <"Buying time if things go wrong in a RAS">.

This was what @plantbrain said in 2011 <"Oxygen in a planted tank.">

cheers Darrel

 

[LMuhlen]

This was what @plantbrain said in 2011 <"Oxygen in a planted tank.">

I noticed that in his post and in others, it is said that the dry/wet section needs to be sealed to prevent CO2 degas. Wouldn't that eventually prevent O2 dissolution as well? How does the O2 get replenished in the sealed chamber?

 

[dw1305]

Hi all,

Wouldn't that eventually prevent O2 dissolution as well? How does the O2 get replenished in the sealed chamber?

It would definitely effect oxygen diffusion if it was totally sealed. I'm guessing that it has a much greater effect on retaining elevated CO2 in the water? Unfortunately I wasn't interested in planted tanks, or CO2, when we used them.

In wastewater work one reason people liked trickle filters was that they were very effective at out-gassing CO2, to the extent that if they weren't outside they need to be in very well ventilated enclosures to avoid asphyxiating the workforce.

cheers Darrel