-
You are viewing the forum as a Guest, please login (you can use your Facebook, Twitter, Google or Microsoft account to login) or register using this link: Log in or Sign Up
amount of C02 required based on KH / mixing RO with tap water
- Thread starter Paul195
- Start date
AverageWhiteBloke
Member
Haha, finally the dog got it. Don't get me wrong, I like to understand the numbers and what they mean but often I find people will chase numbers and miss the wood in the trees. I think my reasoning changed when I had an instance where I was away from my tank for an extended period with no intervention from me, no lighting other than from a window or filtration or dosing (fair enough it was in summer) After 5/6 weeks the tank looked OK as it happened, algae was at a minimum as the algae eaters hadn't been fed and in fact had started to make a start on the plants. Plants were a bit on the weedy side but still looking good.
Got me thinking, if this tank can get by on its own, is there any reason why I should obsessively be dosing at the same time everyday measuring to the mil and chasing co2 and ph numbers and still run into issues now and again. Over accelerating growth through lighting just brings in a load of problems you can do without. It's like running on the ragged edge, one slip in cleanliness, flow, nutrients or co2 and a problem is waiting to jump on you. I went forward with a new approach, put SOME light over a tank and watch the plants. No signs of co2 or nutrient related issues and new growth on the plant and maybe chance my arm with a touch more light. Then the options are some co2 and more ferts or leave the lights alone. Keep doing this incrementally without rushing things while plants adapt to the changes and find where I personally want to be which is low maintenance and healthy plant growth. I'm not really bothered if I have 80% of my lights left to use, its there if I ever fancy it and it keeps my leccy bill down 😉
Steady growth for plants in my experience grows a better formed all round better looking plant. Most people will put some plants in and before they have even had chance to put some roots down throw everything including the kitchen sink at them and spend the next six months in the forum algae fighting in denial that this can't be happening because my co2 is 30ppm, DC is lime green, they are dosing more ferts than ever could be used and the lighting puts out more power than Blackpool in November.
Problem is the plants don't visit this forum and very rarely do as they're told.
Got me thinking, if this tank can get by on its own, is there any reason why I should obsessively be dosing at the same time everyday measuring to the mil and chasing co2 and ph numbers and still run into issues now and again. Over accelerating growth through lighting just brings in a load of problems you can do without. It's like running on the ragged edge, one slip in cleanliness, flow, nutrients or co2 and a problem is waiting to jump on you. I went forward with a new approach, put SOME light over a tank and watch the plants. No signs of co2 or nutrient related issues and new growth on the plant and maybe chance my arm with a touch more light. Then the options are some co2 and more ferts or leave the lights alone. Keep doing this incrementally without rushing things while plants adapt to the changes and find where I personally want to be which is low maintenance and healthy plant growth. I'm not really bothered if I have 80% of my lights left to use, its there if I ever fancy it and it keeps my leccy bill down 😉
Steady growth for plants in my experience grows a better formed all round better looking plant. Most people will put some plants in and before they have even had chance to put some roots down throw everything including the kitchen sink at them and spend the next six months in the forum algae fighting in denial that this can't be happening because my co2 is 30ppm, DC is lime green, they are dosing more ferts than ever could be used and the lighting puts out more power than Blackpool in November.
Problem is the plants don't visit this forum and very rarely do as they're told.
AverageWhiteBloke
Member
I guess in conclusion, it's best to let the plants tell you what they want instead of you telling the plants what they should get maybe.
Edvet
Member
Hi all,
cheers Darrel
That one. Good things come to those who wait.
I blame the plants as well, they won't read , or do what you tell them to do, and they have <"moved the goal-posts">.
Quality.So patience and observation
cheers Darrel
Yes. Exactly.
No.
The reason for the variance is because no two hobbyists or tanks are identical. Temperature is different, pressure is different, injection technique is different, flow/distribution is different, lighting is different, plant mass and plant species are different.
Many people blame their KH for their CO2 failures. This is a self induced hypnosis. They fail as a direct result of their poor CO2 injection techniques and they compare their tank's water parameters with their neighbor's tank, which you should never do. It is estimated that over 90% of the failures in planted tanks are a result of poor CO2 techniques.
Yes.
By doing so you you improve the efficiency and retention of the gas in water. Additionally, you can reduce the intensity (not necessarily the duration) ogf the light striking the plants. This will reduce their demand for CO2 but will also slow their growth rate, which is actually a good thing because it means less organic waste ejected in the tank. Less lighting intensity also reduces the demand for nutrition.
As I mentioned before, there are only three water parameters that have an effect on CO2 dissolution in water; Temperature, Pressure and Salinity. All other parameters are irrelevant.
Cheers,
Paul195
Member
- Joined
- 31 Dec 2012
- Messages
- 162
My PH is 8 and my KH is 4. this equates to 1.2ppm. Ceg mentioned previously that if I have a KH of around 4-6 then I could aim for a PH drop of 1. But according to the chart, dropping 1 point to PH7 would only provide 12ppm CO2. According to the chart I would need to drop to 6.6 from 8 to get 30ppm.
According to the chart, If my PH is 8 and my KH is 4, this equates to 1.2ppm. If my PH is 7 and my KH is 4, this equates to 12ppm. The way that I have been interpreting the chart is that at the particular KH of your tank water, the starting PH of your water decides how much CO2 is present before CO2 addition, and if you start with a PH of 7 you would already have 12ppm and would only need to drop from 7 to 6.6 to get the magic figure. If this is the case and 12ppm was already present, surely less gas would be needed to add the additional 18ppm than would be required at PH8 where you would need an additional 28.8ppm ?
Sorry... still confused
AverageWhiteBloke
Member
The initial measure before injection doesn't mean that's how much co2 is in the water to start with. It's a measure of the bases and acids. Some of it could be co2 but with good surface agitation there will be very little co2 present.
Sent from my STH100-2 using Tapatalk
Sent from my STH100-2 using Tapatalk
Hi all,
This equilibrium is stable at pH8, and water with any carbonate content will read ~pH8. There is a more complete discussion at <"Aquasoil pH increase">.
cheers DarreI
It is a bit strange, but carbonates are insoluble in pure water, but soluble in acids (proton donors). If you don't have any bases (proton acceptors) present, other than carbonates, the pH of the water is dependent upon the CO2(H2CO3) ~HCO3- ~ CO3 equilibrium, and the amount of H2CO3 (carbonic acid) present relates to the 400ppm of CO2 in the atmosphere. The theoretical amount of dissolved CO2 is about 0.5ppm, and only a minute proportion of this becomes H2CO3.
This equilibrium is stable at pH8, and water with any carbonate content will read ~pH8. There is a more complete discussion at <"Aquasoil pH increase">.
cheers DarreI
As I and others have mentioned repeatedly, you cannot use the chart to determine how much CO2 is in your water. The Chart represents a mathematical relationship between the pH, the Carbonate Hardness (amount of carbonate) and the CO2.Sorry... still confused
Because this chart is basically an Excel spreadsheet of the equation mentioned by Darrel it cannot represent anyones water unless that water is prepared in accordance with the data used to build the chart.
The chart makes the following assumptions;
1. That the only acid in the water is Carbonic acid. - This is never true in a tank or in any natural body of water.
2. That the only source of alkalinity in the water is Carbonate ion. - This is only seldom true as there are many possible substances which contribute to alkalinity.
3. That you are able to accurately measure Carbonate Hardness - This is also rarely true as hobby grade test kits cannot tell the difference between Carbonate and other alkaline substances.
As AWB mentions, the way to use the chart is to use the differences between a starting value and the target value in order to determine the change in CO2. The chart will not help you to determine absolute values, and neither is it necessary to know those values. But, if you change your CO2 by 20 ppm, or by 30 ppm, or by whatever target amount, then that is a good enough estimate. Use these estimates in conjunction with your dropchecker to ensure that the estimate is in the safe zone.
Cheers,
AverageWhiteBloke
Member
That's why it's called a "drop check" Paul, you're measuring the drop to calculate how much co2 you now have compared to before injecting based on the assumption that before you started injecting there wasn't any. (Or very little, not worth bothering about)
There could have been if the gas from the previous day hasn't gassed of through lack of surface agitation or scum on the water effectively sealing it in or trapped in the filter but rarely.
That's where the drop checker solution comes in, the parameters Clive was talking about which would make that spread sheet chart work is a solution where the only source of alkalinity is carbonate ion and distilled water made up to 4dkh. It's isolated from the tank water so doesn't care what your other tank parameters are, also isolated from any acids of any kind that may be in your tank water so effectively the only thing that can get in there is gas. Because co2 is acidic the gas that gets in there will acidify the water and change the colour of the PH fluid. General rule of thumb, lime green about right. Yellow bit much and blue not enough.
Both the above techniques have their downfalls as pointed out in previous posts, but you can use both techniques and correlate your findings to give you a ball park idea of where you are regarding co2.
That's why I said earlier on not to get too bogged down with the numbers as neither are that accurate but the best we have for now. Co2 issues can still show in plants even with good colours and numbers if the flow isn't right.
Sent from my STH100-2 using Tapatalk
There could have been if the gas from the previous day hasn't gassed of through lack of surface agitation or scum on the water effectively sealing it in or trapped in the filter but rarely.
That's where the drop checker solution comes in, the parameters Clive was talking about which would make that spread sheet chart work is a solution where the only source of alkalinity is carbonate ion and distilled water made up to 4dkh. It's isolated from the tank water so doesn't care what your other tank parameters are, also isolated from any acids of any kind that may be in your tank water so effectively the only thing that can get in there is gas. Because co2 is acidic the gas that gets in there will acidify the water and change the colour of the PH fluid. General rule of thumb, lime green about right. Yellow bit much and blue not enough.
Both the above techniques have their downfalls as pointed out in previous posts, but you can use both techniques and correlate your findings to give you a ball park idea of where you are regarding co2.
That's why I said earlier on not to get too bogged down with the numbers as neither are that accurate but the best we have for now. Co2 issues can still show in plants even with good colours and numbers if the flow isn't right.
Sent from my STH100-2 using Tapatalk
AverageWhiteBloke
Member
Just to clear up another point Paul in case you were wondering, when you do the PH drop using a ph pen and kh test the PH pen will measure other acids and bases of course and as Clive pointed out the KH test will also measure other things other than carbonates. That's why the pre injection test is insignificant and just a start value to work from. Because you are dealing with a short period of time, usually a few hours between co2 on and lights on it is assumed that the water parameters haven't changed since the first test other than the co2.
As you can see, lot of assumptions, mixed with time delays, test kits that aren't that accurate, and only measuring one particular point at one particular time and ph fluid colour being affected by the lighting. No need to be trying to get within 2ppm if you want to keep your sanity 😉
Sent from my STH100-2 using Tapatalk
As you can see, lot of assumptions, mixed with time delays, test kits that aren't that accurate, and only measuring one particular point at one particular time and ph fluid colour being affected by the lighting. No need to be trying to get within 2ppm if you want to keep your sanity 😉
Sent from my STH100-2 using Tapatalk
My starting pH when CO2 comes on varies throughout the week, then changes big time after water change, but the CO2 injection rate is constant. Some days the drop is 1.2pH others it's 1.5pH, but who's pH controler or pen is accurate anyway. DC is normally light yellow.
Nice thing about pH controler is the probe is on a lead so the probe can be moved anywhere in tank not just the surface, which is helpful IMO
Sent from my Moto G (4) using Tapatalk
Nice thing about pH controler is the probe is on a lead so the probe can be moved anywhere in tank not just the surface, which is helpful IMO
Sent from my Moto G (4) using Tapatalk
AverageWhiteBloke
Member
Indeed, obviously the Drop Checker can be moved about as well. I was going to get one of those Seneye things at one point so I could get readings from anywhere in the tank but unfortunately it only logged ph down to 6.4 and with my very soft water it wasn't low enough.
I was talking to one of the sales heads from Seneye who was saying that later this year they are bringing out a planted tank version but it was still in production. I suggested PH should be able to go lower than 6.4 for the soft water people and he said he would pass that on to the team so you never know.
Again though, Whatever we get the plants will always tell you more. I'm free from co2 madness for now, just running a low tech although I will be getting back into it soon. I'm finding if you have dimming it's far easier to mess with lighting than all the other stuff but then again I keep planted tanks and fish as a hobby long term rather than temporary show stoppers.
Sent from my STH100-2 using Tapatalk
I was talking to one of the sales heads from Seneye who was saying that later this year they are bringing out a planted tank version but it was still in production. I suggested PH should be able to go lower than 6.4 for the soft water people and he said he would pass that on to the team so you never know.
Again though, Whatever we get the plants will always tell you more. I'm free from co2 madness for now, just running a low tech although I will be getting back into it soon. I'm finding if you have dimming it's far easier to mess with lighting than all the other stuff but then again I keep planted tanks and fish as a hobby long term rather than temporary show stoppers.
Sent from my STH100-2 using Tapatalk
Paul195
Member
- Joined
- 31 Dec 2012
- Messages
- 162
Many thanks to everybody who has posted to help me try to understand this.
I already have a drop checker installed, I was mostly trying to understand the way that the chart works (point taken that is only an estimate and should be used in conjunction with the DC).
Ok so to summarize....
1. Find the KH of your water
2. Find out what PH corresponds to the level of CO2 you are trying to achieve (usually 30ppm)
3. Drop to that PH value from whatever the PH of your water is before injection.
4. Cross reference with the drop checker to check the colour is lime green (or in some cases slightly yellow)
Correct ?
I already have a drop checker installed, I was mostly trying to understand the way that the chart works (point taken that is only an estimate and should be used in conjunction with the DC).
Ok so to summarize....
1. Find the KH of your water
2. Find out what PH corresponds to the level of CO2 you are trying to achieve (usually 30ppm)
3. Drop to that PH value from whatever the PH of your water is before injection.
4. Cross reference with the drop checker to check the colour is lime green (or in some cases slightly yellow)
Correct ?
AverageWhiteBloke
Member
By jove, I think he's got it 😉 nice one pal haha. It it can boggle your mind at times. I often find things in growing plants turn out to be the exact opposite of what would seem logical.
Last point would be, after all that, just remember the drop checker has a delay so the real time reading you take with the pen will roughly match up with the DC in about an hour or so time. Plus, just to make things a bit more interesting. The DC only measures in that particular area of the tank, likewise the PH pen only measures the top layer as the gas is leaving the tank. The plants will have the final say. If you have plants that are showing signs of co2 issues then you have bad flow in that area regardless of what the PH pen and DC are saying.
90% of the gas you inject doesn't even end up in the plant, the gas wants to get out of the tank as fast as possible in warm water and play in the atmosphere with all the other gases. Look at it like this. If 100 co2 atoms go past a plant it can only grab 10 of them (ball park for simplification) with high lighting the plant is going to need all it can get hold of. If you have an area of the tank with little co2 but getting bashed with the same high light it isn't even going to grab the 10=co2 related plant issues. Even if the DC is a nice colour and the pen is telling you what you want to hear.
If you suspect you have a place of poor water movement the gas isn't getting to, resolve that by altering spray bars and outlets or pumps whatever. That place is a good place to put your drop checker, if things look good there chances are the rest of the tank is good to.
Enjoy injecting gas haha it's a bit like rubbing your belly while rubbing your head with the other.
Then the plant mass will change or you have more surface agitation when water levels drop and it all changes again.
Sent from my STH100-2 using Tapatalk
