# Water parameters suitable for CO2 injection



## willsy (3 Apr 2018)

Hi,

Just in the process of setting up my new aquarium.

Been keeping planted tanks for a few years now, but this is my first high tech attempt!

Currently my equipment is:

180L Aquascaper aquarium.
CO2 injection (currently 2 to 3 bps without fish).
Heavily planted.
EI 5 days per week.
Twinstar 900s LED.

My question is regarding my water parameters...

I was using 50/50 RO/tap previously, but as per another recommendation on here, I have now moved to 75%RO/25% tap. 

I carried out a water change at the weekend and it was the first time ever I've seen the plants pearling in all these years! So looks like a good sign...

The thing is my parameters are the following for the mixed water before putting in the aquarium:

ph: 6.6
kh: 4
gh: 6

Is this OK for CO2 injection? I hear of 1 point drop is optimal for CO2 injection, but this would take me to 5.6ph would it not? Not sure about all this 1 point drop stuff! 

I'm keeping Tetra's, so I think this should be good for them at least!

Cheers 

Will.


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## Konsa (3 Apr 2018)

Hi Will.
If U are trying to measure your ph drop.U need to get a baseline for your tank .This should be done before CO2 comes on in morning or put water in sth and let it rest for 24h.U will aim for 1 point drop from that.
Regards Konsa


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## foxfish (3 Apr 2018)

That is a very good idea to get your C02 right & plants growing before adding fish 
Counting bubbles per second is a helpful check to make sure you gas is running & great as a reference point but only for your specific tank.
You will need to use a drop checker as another very useful guide to monitor C02 content & a PH profile will offer extremely helpful information.
You might find your own set up will require a lot more BPS that Johns down the road does, every tank is different.
Why are you using 75% RO water?


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## Edvet (3 Apr 2018)

With these parameters you should be able to get the one point drop, maybe even a bit more. ( the softer the water the larger pH drop you will get from a given amount of CO2)
For cardinal tetras the softer water will be good indeed, for Neons it isn't necessary because they will be tank bred most likely.
Don't stare yourself to death on the pearling, even in high growing, high light tanks pearling doesn't always occur, and just after a waterchange there is a chance there is more CO2 in the tank, and changes in watertamp because of the wc can give pearling too.
BTw you can add CO2 to "liquid rock"too ( very hard water) the adding of CO2 isn't changed ( only the pH drop you'll get), you can get the same amount dissolved.


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## willsy (3 Apr 2018)

Edvet said:


> With these parameters you should be able to get the one point drop, maybe even a bit more. ( the softer the water the larger pH drop you will get from a given amount of CO2)
> For cardinal tetras the softer water will be good indeed, for Neons it isn't necessary because they will be tank bred most likely.
> Don't stare yourself to death on the pearling, even in high growing, high light tanks pearling doesn't always occur, and just after a waterchange there is a chance there is more CO2 in the tank, and changes in watertamp because of the wc can give pearling too.
> BTw you can add CO2 to "liquid rock"too ( very hard water) the adding of CO2 isn't changed ( only the pH drop you'll get), you can get the same amount dissolved.



I am planning to get a large group of Cardianal Tetra's and a group of Ember Tetra's...

So if (for example) I started in the morning with a ph of 6.6, am I trying to achieve a drop to a ph 5.6. Is this correct? Just seems rather low to me, or is this OK?

I do have a drop checker and this is going lime green, so I think it's OK from that respect!?

Thanks

Will.


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## foxfish (3 Apr 2018)

willsy said:


> I do have a drop checker and this is going lime green, so I think it's OK from that respect!?



As the ideal C02 content during the lighting period is possibly the most difficult aspect to achieve, it will be a good idea to back up your DC with a PH profile.
2-3 bps is unusually low for a 180l tank but as  BCs can vary from one to another, your bubble count might be fine?
A PH profile tells you many things that a drop checker wont. Ideally you want to get 30ppm of Co2 in the tank at lights on.
You need to start the profile at lease three hours before your lights come on, or one hour before the C02 starts up.
If you have good flow & distribution then you should be able to hit 30ppm of C02 within two hours of the gas coming on & that should coincide with the lights coming on.
Whatever the PH readings are at that time, you should now be able to maintain that level until lights off.
As it is very difficult to actually measure the exact C02 content we have to rely on a combination  or factors like a lime green DC, PH profile & how the plants are reacting or if we have certain types of algae. That is why you should keep lights low & no fish until you have established a good balance.


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## willsy (3 Apr 2018)

foxfish said:


> As the ideal C02 content during the lighting period is possibly the most difficult aspect to achieve, it will be a good idea to back up your DC with a PH profile.
> 2-3 bps is unusually low for a 180l tank but as  BCs can vary from one to another, your bubble count might be fine?
> A PH profile tells you many things that a drop checker wont. Ideally you want to get 30ppm of Co2 in the tank at lights on.
> You need to start the profile at lease three hours before your lights come on, or one hour before the C02 starts up.
> ...



Thanks for the info foxfish.

I'm still a little confused by the CO2 ph/kh reference table though. I notice that the intersection of 30ppm is ph = 6.6 and kh = 4.

The thing is that my starting point _before_ co2 injection and lights on is a ph of 6.6. and kh = 4! 

Does this mean that my ph and kh will remain the same if I am achieving 30ppm CO2?

Thanks

Will.


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## dw1305 (3 Apr 2018)

Hi all,





willsy said:


> I'm still a little confused by the CO2 ph/kh reference table though. I notice that the intersection of 30ppm is ph = 6.6 and kh = 4.
> 
> The thing is that my starting point _before_ co2 injection and lights on is a ph of 6.6. and kh = 4!
> 
> Does this mean that my ph and kh will remain the same if I am achieving 30ppm CO2?


The CO2/dKH/pH reference table only really works with a drop checker when you are adding CO2. You can't use it to work out how much CO2 is present in your water, it will always be in the region of 0.5 ~ 3ppm when you aren't adding CO2. 

cheers Darrel


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## Edvet (3 Apr 2018)

willsy said:


> Just seems rather low to me, or is this OK?


Don't worry about the pH drops due to CO2, these wont affect the fish, no matter what people say.
Basically: just do the pH profile to make sure the plants get the CO2 they need, make sure you have ample distribution, do regular checkups on the pH, more growth means more plantmass and less flow, so more CO2 needed


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## Zeus. (3 Apr 2018)

I completly ignore kH and gH ( my water is hard) as others have said, pH profile with colour change on DC lime green ( I have mine light yellow to clear but carries risks/benefits). Stable pH drop for photoperiod, pH on time dependant on how long to takes to get to target pH. Starting pH varies on mine pre WC to post WC but target remains the same. Drop varies from 1.0 to 1.6pH. increasing the light intensity increases the CO2 demand also, so worth checking after intensity increase as injection rate my need increasing, I increase to injection pressure as my BPS is very high and counting bubbles is near impossible on 500l tank, on 50l tank BPS easy to count.


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## Mark Grigg (6 Apr 2018)

willsy said:


> Hi,
> 
> Just in the process of setting up my new aquarium.
> 
> ...


I’m with you here Will, I’m new to the planted aquarium but have fish experience, I’ve just set up a new 400l tank and have tried to automate it as much as possible, one alteration was auto water change, in my wisdom (or maybe not now) was to add an RO unit, after some drilling through walls and discrete plumbing into the utility (don’t tell the wife) I tested the RO water v the tap, my ph dropped from the tap of 7:2 to around 6.1, I had the same conundrum that if I add CO2, will I further reduce my ph.

After taking advice from members I removed the resin chamber but kept the micro filter and carbon section and plumed direct to the float valve. I still need to understand if the carbon filter will remove any elements that I really need in the tank,

I’m keen to see how this works out for you moving forwards. I’m now doing a 21l water change at 12:00 and a 7l change at 18:00.

I do have good soft water based on feedback, so understand this maybe different.


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## willsy (7 Apr 2018)

Mark Grigg said:


> I’m with you here Will, I’m new to the planted aquarium but have fish experience, I’ve just set up a new 400l tank and have tried to automate it as much as possible, one alteration was auto water change, in my wisdom (or maybe not now) was to add an RO unit, after some drilling through walls and discrete plumbing into the utility (don’t tell the wife) I tested the RO water v the tap, my ph dropped from the tap of 7:2 to around 6.1, I had the same conundrum that if I add CO2, will I further reduce my ph.
> 
> After taking advice from members I removed the resin chamber but kept the micro filter and carbon section and plumed direct to the float valve. I still need to understand if the carbon filter will remove any elements that I really need in the tank,
> 
> ...


Hi Mark,

Thanks... Looks like there are at least two newbies here! Everyone else is a pro! 

I love the fact that my plants are pearling though. I feel like I've partly joined the club. 

Anyway I've been checking and I seem to have a pH of 7.6 before lights on and a pH of 6.6 an hour and a half after the CO2 goes on. So I think I'm actually all good to this regard. I guess checking the new water out of the aquarium gives false readings...

Just now have an ammonia reading of 0.25. This would be because of the dirted bottom! Hopefully this should even out soon. Dying to get the first shrimps in there!

Everything is going well and I'm getting very good growth and no algae (yet). Long may it last!

Sorry I've not been much help to you Mark. Hope you get your side sorted! Not able to offer any advice I'm afraid.

Cheers.

Will


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