I’m using TNC complete fertiliser at the minute, I’ve low nitrates and it is such a good fertiliser. Fighting to grow my hairgrass carpet, it’s trying its best
Fluctuating KH
- Thread starter Aktasak
- Start date
How much time do you wait after remineralising the water you use and did you test it ?
At the moment if your substrate is actively hardening the water, you have to use "slightly" lower hardness in your source water to maintain the softness of your tank
Your new water should stand a while after been mixed and test it next time. if it's too hard, cut it back with more RO. Your recipe will become easier and more precise each time.
At the moment I would not add too much liquid fertilizer. If the plants uptake is low it's a contributor to higher hardness.
At the moment if your substrate is actively hardening the water, you have to use "slightly" lower hardness in your source water to maintain the softness of your tank
Your new water should stand a while after been mixed and test it next time. if it's too hard, cut it back with more RO. Your recipe will become easier and more precise each time.
At the moment I would not add too much liquid fertilizer. If the plants uptake is low it's a contributor to higher hardness.
I always remineralise on the day of the water change, I will remineralise the water the day before in future! I’ve always done it this way so I thought it was ok.
I did not test it as I used the dosage calculated for both on Seachem’s website for both products. Will definitely test it in the next back as well.
I’m still new to RO so I am still learning.
Even with pure RO/DI water, after you add the minerals they will still react for a while. Wait a day to let it settle.
A good technique is to aerate the water with an air stone, RO/DI water has been depleted from Co2 resulting with a more basic content. Bringing the water back to atmospheric Co2 level will acidify the water.
I aerate my RO directly and when I remineralize the source water PH is under 6. when I add the minerals and mix them my PH goes up to 7 then 24h later it reads 7.6
If I don't aerate the source water, is at 7 and PH goes up to 8.4 after 24H. Then it goes back down to 7.6 after aeration.
When CO2 dissolves in water it forms carbonic acid, which dissociates to release hydrogen ions (H+). An increase in (H+) ions lowers the pH.
So aerating the water previously to adding it to the aquarium prevent the leveling phenomena to occur in it.
A good technique is to aerate the water with an air stone, RO/DI water has been depleted from Co2 resulting with a more basic content. Bringing the water back to atmospheric Co2 level will acidify the water.
I aerate my RO directly and when I remineralize the source water PH is under 6. when I add the minerals and mix them my PH goes up to 7 then 24h later it reads 7.6
If I don't aerate the source water, is at 7 and PH goes up to 8.4 after 24H. Then it goes back down to 7.6 after aeration.
When CO2 dissolves in water it forms carbonic acid, which dissociates to release hydrogen ions (H+). An increase in (H+) ions lowers the pH.
So aerating the water previously to adding it to the aquarium prevent the leveling phenomena to occur in it.
TwoTankAmin
Fish Connoisseur
Bicarbonate is in equilibrium with carbonic acid, and carbonic acid is in equilibrium with carbon dioxide.
[1] HCO3−⇔CO32−+H+
[2] H2CO3⇔HCO3−+H+
[3] CO2(aq)+H2O⇔H2CO3
[4] CO2(g)⇔CO2(aq)
When RO permeate passes through a degasifier, the carbon dioxide gas is displaced by oxygen and nitrogen from the air that is blown through the solution. The loss of carbon dioxide cause a shift in the equilibrium reaction to the left (see Eq. [1],[2],[3]). The bicarbonate reacts with acid protons to form more carbon dioxide (Le Chatelier’s Principle), and in turn, carbonate proceeds to react with acid protons to replace bicarbonate. Since H+ is being consumed, there will be a lower concentration of free [H+], resulting in a higher pH.
This higher pH does not help reduce corrosion. The higher pH was caused as a result of the equilibrium shifting in favor of forming more CO2, at the expense of alkalinity. Higher pH normally provides a protective effect because of the formation of ferrous carbonate, copper carbonate and lead carbonate scales on the corresponding metals. But in this case, the carbonate species are being reduced, not increased. Furthermore, this higher pH water will not be buffered, and by the time it reaches the point of use (POU), the pH will have decreased. Therefore, a higher pH from the addition of sodium hydroxide has a very different effect on water chemistry than a higher pH from degasification of CO2.
Where possible, it is best to avoid gassing off CO2, and instead, adding a caustic solution to convert CO2 to alkalinity.
[5] H2CO3+OH−⇔HCO3−+H2O
[6] HCO3−+OH−+CO32−+H2O
Carbonates react with corroding metals to form protective metal carbonates and also provide a pH buffer throughout the distribution system.
The above is from Calcium (Ca) and water- Calcium and water: reaction mechanisms, environmental impact and health effects
In theory RO/DI water should be neutral. But is contains less CO2. However, this is a pretty temporary condition. I know this because I have been batchig RO?DI water now for a number of years for use in a tank with Altum angels. For this I have a continual monitor for Conducrtivity/TDS, Temperature in F or C and pH.
I batch my "pure water" into a 20 gal. Rubbermaid garbage can. Because I am changing my tap parameters, they tend to be less stable over time at a any given pH and TDS level. I target the tank water fto be pH 6.0 and TDS in the 60w 60 ppm range. Both of these numbers tend to drift higher between water changes. So, I know what they are in the tank when I need to make up the changing water which is partly intended to bring the parameters back down.
With every water change I need to lower the pH and the TDS. I do this by shifting the digital probes from the tank to the Rubbermaid. But i cannot do this until I have added enough of my tap water so that the pH and especially the TDS are where I need them. The monitor does not like super low pH or 0 TDS water. So, I am mixing 11 parts of RO/DI with my tap which is 7.0 and about 83 to 115 ppm of TDS. That TDS fluctualtion is due to local rainfall levels. When normal the water is 7.0 and 83 ppm. During times of drought those numbers rise, especially the TDS which hit about 115 ppm. When there is a serious bout of heavy rains\ , the tap numbers drop. The exess rainfall can lower the pH to maybe 6.8 but it can drop the TDS into the low 50s ppm.
But what is most interesting is the pH. It drops once the RO/DI water is in the RUbbermaid. Since the RO/DI goes in first the probes do not usually until most of the tanp has been added. This is done with mostly hot water from the tap as I need to get the changing water to 85F. I run a circulating pump in the Rubbermaid in order to mix it thoroughly. But, I have tested for pH in the pure water and it is always acid. That is due to the CO2 being resored during the pouring and pump circulation going on.
There are normal levels for CO2 and oxygen (among other things) which are normal for the atmosphere and dissolved in the water. Given a bit of surface agitation, and those numbers will usually balance out at their equilibrium values. My tap water from our well contains excess CO2 which cause the pH to be in the low 6s when it comes from the tap. But given the chance for the gasses to exchange this fairly quickly chnages the pH to its natural pH around neutral.
And then the "alchemy" starts. I am mixing the RO/DI to tap at an 11/9 ratio. In the past I have tested the pH of the RO/DI and it is normally acid as explained above. This is due to the information quoted at the begining of the post. In less scientific terms, the RO/DI has no KH which is what holds up the level of pH. In our tanks almost all of the KH comes from carbonates and bicarbonates. These are also used by the nitrifying bacteria along with CO2 to supply the inorganic carbon that they require. The tap water contains KH and this works to prevent the pH in the new water from crashing. In fact, I often have to add some muriatic acid to the new water to get the pH down to where I need it to be so it will bring the tank pH back to 6.0 or a bit lower.
Another way to see this sort of chemical change in parameters happens is when I start up my bio-farm to cycle a number of filters to go into new tanks going up. I am cycling multiple filters in a 40 gal breeder tank which will end up in 220 gals of water spread over 8 new tanks. As those 8 tanks get their needed filters I then stock the tanks fully or even a tad more right away.
The biggest problem when running the bio-farm is the consumption of the KH by the bacteria and a resulting drop in the pH which effectively slows the cycle to a crawl. To combat this I add a couple of bags of crushed coral to the bio-farm. These are dissolved by acid water adding KH and thus raising/holding up the pH. I actually monitor this using a TDS pen. Because KH contributes to TDS and coral etc. are calcium carbonate. The carbonate works on the pH and the calcium acts to give the GH a small boost. This is because calcium does not readily dissolve in water unless the water is acid.
So when I add those bags of coral to the bio farm, I am getting way more carbonates added than calcium. I do not mind a small increase in the GH because it will not persist when the filters go into the new tanks. The amount of calcium in the water in the Cubefilters is so little is has no effect on the tank water.
I have always tended to refrain from changing my water parameters aside from temperature in all my tanks save the one for Altums. It takes a lot of work to do this in a stable manner. In an acid water tanks the bacteria have adapted to working at that pH and using ammonium. If I allowed the pH to rise to 7.0 or higher, I am increasing both the KH and GH. For acid water fish the lower hardness is more important than the acid level in the water. For the bacteria they would switch to using ammonia which they prefer. If I then correct the pH back to 6.0, the bacteria have to readapt and this might mean they are not going to be keeping the tank safe for some amount of time.
I actually use a bit of the SeaChem Equilibrium in a couple of my heavily planted tanks where there are also shrimp and snails. The demands of the plants and inverts are so great that they deplete the water of thins which contribute to hardness. I need to supplement these things to some extent. However my dosing is pretty low as the point is not to raise the parameters noticeably but to provide those things that are getting used up faster than would be normal in my other tanks some of which may not have any plants and/or inverts.
What I learned is that water in the wild is not stable. The parameters go through changes every day. The temp. changes, the hardness changes and so does the pH and kH. However, the changes are not sufficient to bother the fish. They are naturally caused by the changes that occur between day and night times and also due to seasonality factors.
Our fish have adapted to live in ranges and not an absolute number which should never change. This is one of my favorite urban aquarium myths to confront. Water parameters in nature do fluctuate. No respectable site or written information ever lists an absolute number for the needs of any given species. These are always given as ranges. For sure, not all sites will have the exact same numbers, but they all have ranges for them.
[1] HCO3−⇔CO32−+H+
[2] H2CO3⇔HCO3−+H+
[3] CO2(aq)+H2O⇔H2CO3
[4] CO2(g)⇔CO2(aq)
When RO permeate passes through a degasifier, the carbon dioxide gas is displaced by oxygen and nitrogen from the air that is blown through the solution. The loss of carbon dioxide cause a shift in the equilibrium reaction to the left (see Eq. [1],[2],[3]). The bicarbonate reacts with acid protons to form more carbon dioxide (Le Chatelier’s Principle), and in turn, carbonate proceeds to react with acid protons to replace bicarbonate. Since H+ is being consumed, there will be a lower concentration of free [H+], resulting in a higher pH.
This higher pH does not help reduce corrosion. The higher pH was caused as a result of the equilibrium shifting in favor of forming more CO2, at the expense of alkalinity. Higher pH normally provides a protective effect because of the formation of ferrous carbonate, copper carbonate and lead carbonate scales on the corresponding metals. But in this case, the carbonate species are being reduced, not increased. Furthermore, this higher pH water will not be buffered, and by the time it reaches the point of use (POU), the pH will have decreased. Therefore, a higher pH from the addition of sodium hydroxide has a very different effect on water chemistry than a higher pH from degasification of CO2.
Where possible, it is best to avoid gassing off CO2, and instead, adding a caustic solution to convert CO2 to alkalinity.
[5] H2CO3+OH−⇔HCO3−+H2O
[6] HCO3−+OH−+CO32−+H2O
Carbonates react with corroding metals to form protective metal carbonates and also provide a pH buffer throughout the distribution system.
The above is from Calcium (Ca) and water- Calcium and water: reaction mechanisms, environmental impact and health effects
In theory RO/DI water should be neutral. But is contains less CO2. However, this is a pretty temporary condition. I know this because I have been batchig RO?DI water now for a number of years for use in a tank with Altum angels. For this I have a continual monitor for Conducrtivity/TDS, Temperature in F or C and pH.
I batch my "pure water" into a 20 gal. Rubbermaid garbage can. Because I am changing my tap parameters, they tend to be less stable over time at a any given pH and TDS level. I target the tank water fto be pH 6.0 and TDS in the 60w 60 ppm range. Both of these numbers tend to drift higher between water changes. So, I know what they are in the tank when I need to make up the changing water which is partly intended to bring the parameters back down.
With every water change I need to lower the pH and the TDS. I do this by shifting the digital probes from the tank to the Rubbermaid. But i cannot do this until I have added enough of my tap water so that the pH and especially the TDS are where I need them. The monitor does not like super low pH or 0 TDS water. So, I am mixing 11 parts of RO/DI with my tap which is 7.0 and about 83 to 115 ppm of TDS. That TDS fluctualtion is due to local rainfall levels. When normal the water is 7.0 and 83 ppm. During times of drought those numbers rise, especially the TDS which hit about 115 ppm. When there is a serious bout of heavy rains\ , the tap numbers drop. The exess rainfall can lower the pH to maybe 6.8 but it can drop the TDS into the low 50s ppm.
But what is most interesting is the pH. It drops once the RO/DI water is in the RUbbermaid. Since the RO/DI goes in first the probes do not usually until most of the tanp has been added. This is done with mostly hot water from the tap as I need to get the changing water to 85F. I run a circulating pump in the Rubbermaid in order to mix it thoroughly. But, I have tested for pH in the pure water and it is always acid. That is due to the CO2 being resored during the pouring and pump circulation going on.
There are normal levels for CO2 and oxygen (among other things) which are normal for the atmosphere and dissolved in the water. Given a bit of surface agitation, and those numbers will usually balance out at their equilibrium values. My tap water from our well contains excess CO2 which cause the pH to be in the low 6s when it comes from the tap. But given the chance for the gasses to exchange this fairly quickly chnages the pH to its natural pH around neutral.
And then the "alchemy" starts. I am mixing the RO/DI to tap at an 11/9 ratio. In the past I have tested the pH of the RO/DI and it is normally acid as explained above. This is due to the information quoted at the begining of the post. In less scientific terms, the RO/DI has no KH which is what holds up the level of pH. In our tanks almost all of the KH comes from carbonates and bicarbonates. These are also used by the nitrifying bacteria along with CO2 to supply the inorganic carbon that they require. The tap water contains KH and this works to prevent the pH in the new water from crashing. In fact, I often have to add some muriatic acid to the new water to get the pH down to where I need it to be so it will bring the tank pH back to 6.0 or a bit lower.
Another way to see this sort of chemical change in parameters happens is when I start up my bio-farm to cycle a number of filters to go into new tanks going up. I am cycling multiple filters in a 40 gal breeder tank which will end up in 220 gals of water spread over 8 new tanks. As those 8 tanks get their needed filters I then stock the tanks fully or even a tad more right away.
The biggest problem when running the bio-farm is the consumption of the KH by the bacteria and a resulting drop in the pH which effectively slows the cycle to a crawl. To combat this I add a couple of bags of crushed coral to the bio-farm. These are dissolved by acid water adding KH and thus raising/holding up the pH. I actually monitor this using a TDS pen. Because KH contributes to TDS and coral etc. are calcium carbonate. The carbonate works on the pH and the calcium acts to give the GH a small boost. This is because calcium does not readily dissolve in water unless the water is acid.
So when I add those bags of coral to the bio farm, I am getting way more carbonates added than calcium. I do not mind a small increase in the GH because it will not persist when the filters go into the new tanks. The amount of calcium in the water in the Cubefilters is so little is has no effect on the tank water.
I have always tended to refrain from changing my water parameters aside from temperature in all my tanks save the one for Altums. It takes a lot of work to do this in a stable manner. In an acid water tanks the bacteria have adapted to working at that pH and using ammonium. If I allowed the pH to rise to 7.0 or higher, I am increasing both the KH and GH. For acid water fish the lower hardness is more important than the acid level in the water. For the bacteria they would switch to using ammonia which they prefer. If I then correct the pH back to 6.0, the bacteria have to readapt and this might mean they are not going to be keeping the tank safe for some amount of time.
I actually use a bit of the SeaChem Equilibrium in a couple of my heavily planted tanks where there are also shrimp and snails. The demands of the plants and inverts are so great that they deplete the water of thins which contribute to hardness. I need to supplement these things to some extent. However my dosing is pretty low as the point is not to raise the parameters noticeably but to provide those things that are getting used up faster than would be normal in my other tanks some of which may not have any plants and/or inverts.
What I learned is that water in the wild is not stable. The parameters go through changes every day. The temp. changes, the hardness changes and so does the pH and kH. However, the changes are not sufficient to bother the fish. They are naturally caused by the changes that occur between day and night times and also due to seasonality factors.
Our fish have adapted to live in ranges and not an absolute number which should never change. This is one of my favorite urban aquarium myths to confront. Water parameters in nature do fluctuate. No respectable site or written information ever lists an absolute number for the needs of any given species. These are always given as ranges. For sure, not all sites will have the exact same numbers, but they all have ranges for them.
Thank you for your replies! I’ll definitely remineralise a day before the water change in future.
Now, I’m probably going to sound incredibly stupid but I figured I ask anyway:
Do I add Equilibrium and Alkaline buffer dosage according to the volume of water in the tank or the volume of water that I’ve taken out (10L)? Perhaps this is where I’m going wrong.
Now, I’m probably going to sound incredibly stupid but I figured I ask anyway:
Do I add Equilibrium and Alkaline buffer dosage according to the volume of water in the tank or the volume of water that I’ve taken out (10L)? Perhaps this is where I’m going wrong.
Only remineralize the water you are replacing, if the water in the tank is already ok, you want to keep it that way.
If you go with the volume of the tank, the hardness is going to increase accordingly.
Honestly, this is all just so frustrating and annoying to deal with.
I had the water perfect in the old tank and then I switched to this shallow tank with the Aquabasis and that’s where it’s all going wrong. It seems whatever I do, doesn’t help stabilise it.
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