How much Calcium Nitrate to substitute for Potassium Nitrate for a planted high-light tank?

[Zak Rafik]

Hi everyone,

I’m going to start EI fertilization for my 40 days old planted tank (255 litres / 67 US gallons) very soon. It’s a highlight with injected Co2 setup.

Currently I’m dosing with ADA’s Brighty K and Brighty Step 1. But after I read about the immense benefits of EI dosing, I got hooked on it.

In my country, Potassium Nitrate KNO3 is banned for security reason. After some googling, I found out that Calcium Nitrate Ca (NO3)2 is somewhat a better alternative. (Please correct me on this if I’m wrong)

Now that I have received an EI dosing kit from aquariumplantfood.co.uk


The kit came with the following:

Nitrate*

1 x Calcium Nitrate Ca (NO3)2 (instead of Potassium Nitrate KNO3) 500g

Phosphate*

1 x Potassium Phosphate KH2PO4 250g

Magnesium*

1 x Magnesium Sulphate MgSO4 500g


Trace*

1 x Chelated Trace Elements 250g


The mix is to be prepared as follows:

Macro Solution (Mix, Shake & Leave to Dissolve Overnight)

?? tsp Calcium Nitrate

1 tsp Potassium Phosphate

6 tsp Magnesium Sulphate

500ml Water


Micro Solution (Mix, Shake & Leave to Dissolve Overnight)

1 tsp Chelated Trace Elements

500ml Water



I would really appreciate if someone with experience with EI fertilization can advise me on the following:


Is the above mixing quantity the same for all tank sizes or for my tank size do I have to increase or decrease the mineral quantity?


How much Calcium Nitrate do I substitute for Potassium Nitrate for my tank size?

The instruction says 4 tsp for Potassium Nitrate.

So the amount for Calcium Nitrate should be _____tsps?


Apart from Potassium Nitrate is there a better or effective alternative mineral to Calcium Nitrate?


Is it true that when one doses with calcium nitrate, the tank’s GH increases? If so by how much? My tank water is around pH 6.6 before Co2 turns on.


Is there any mineral that is missing in this EI dosing kit, like K source ?


I run a UV light 12 hours a day on timer. But I read in a forum that UV light reacts with trace elements. It was further suggested that if one dose fertilizers in the morning then one should have the UV light run later in the evening? To what extent is this info reliable?


Do I have to prepare the dose in cooled boiled tap water or in distilled water?


I have attached a photo my tank taken today.

Thank you in advance for your info. Cheers 🙂
Raffik

http://i1295.photobucket.com/albums...1-7501-49A6-9775-F52581DDDAD4_zpswfnylbs7.jpg


http://i1295.photobucket.com/albums...7-8B35-4A47-8C2B-E79A40AC97B7_zpsvscdry8y.jpg


http://i1295.photobucket.com/albums...4-7289-4EE1-BB10-6615E5F8CD3F_zpsjcqcqzaq.jpg

 

[GlassWalker]

Generally speaking, you should follow the basic recipe for all tanks. Bigger or smaller tanks just get dosed more or less volume. If you get really advanced and know you have certain parts already, you might be able to customise it, but that would be rather advanced. I get the impression most on this forum don't find that something worthwhile doing and just does standard mix.

I only recently saw the use of calcium nitrate as partial substitute to potassium nitrate on another forum. As a big caution, the other user found a precipitate forming overnight in the macro bottle. We didn't get 100% into this, but we suspect either the formation of calcium sulphate or calcium phosphate were being formed, leaning towards phosphate based on the crystal shapes formed. Either are not very soluble therefore fell out of solution. Therefore you might want to mix and keep the calcium nitrate separate from the rest of the macro.

As a rough calculation, you either need 0.7x or 1.3x the amount of calcium nitrate by volume (compared to potassium nitrate). The first is for anhydrous, the 2nd is for tetrahydrate. So instead of the 4 tsp of potassium nitrate, that would be either 2.7 or 5.1 tsp. I don't think you need to worry about being too exact. I'm assuming the granule size is similar between them so I'm only making a rough consideration for density and proportion that is actually nitrate.

Calcium does contribute to GH, but I'm not up to calculating how much that is.

You do have a potassium source, since it comes with the phosphate. The only possible caution is you will have much less potassium than if you had potassium nitrate. You could use potassium sulphate to boost the potassium.

 

[OllieNZ]

Another option could be magnesium nitrate and using this could replace your mgso4. You will also need to find an additional source of potassium

 

[ceg4048]

How much Calcium Nitrate do I substitute for Potassium Nitrate for my tank size?

Hi Raffik,
No adjustments are necessary for this salt. It delivers a similar amount of NO3. See http://ukaps.org/forum/threads/potassium-nitrate-kno3-purchased-from-internet.16077/

Is it true that when one doses with calcium nitrate, the tank’s GH increases?

Yes. GH = Mg + Ca

Calcium is 17% by weight of the hydrated salt.
If 10 grams of the salt is added to 250L then this will add 1.7g of Ca to the tank giving a concentration of 1700mg/250Kg = 7ppm which is roughly 1 degree of German Hardness.

I suggest that you just get on with it and stop worrying because the plants will not care.

I run a UV light 12 hours a day on timer. But I read in a forum that UV light reacts with trace elements. It was further suggested that if one dose fertilizers in the morning then one should have the UV light run later in the evening? To what extent is this info reliable?

Again, just get on with it and forget about all that.

Do I have to prepare the dose in cooled boiled tap water or in distilled water?

No. If it were me I would just dump the powder directly into the tank. Use any kind of water that makes your life simpler and just carry on.

Cheers,

 

[dw1305]

Hi all,

As a rough calculation, you either need 0.7x or 1.3x the amount of calcium nitrate by volume (compared to potassium nitrate). The first is for anhydrous, the 2nd is for tetrahydrate. So instead of the 4 tsp of potassium nitrate, that would be either 2.7 or 5.1 tsp.

That is the one, it will be the tetrahydrate (Ca(NO3)2.4H2O) whatever it says on the label, because it picks up atmospheric water vapour. If you want the annhydrous form you have to heat it it, drive of the water of crystallization (.4H2O) and store it in a desiccator.

You can use Clive's link, or work these out for yourself with a periodic table, <http://www.ptable.com/>, you just need the RAM of each element to work out the RMM of the compound, and then you divide the RAM of the compound by the RMM to give you a percentage of each element.

In this case Ca = 40, N = 14, O = 16, H = 1 and K = 39.1

So for Ca(NO3)2.4H2O you have 40 + (14+(3*16))*2 = (40 + 124) = 164 for the Ca(NO3)2 and 4 * ((1+1) + 16) = 72 for the 4H2O giving you an RMM of 164+72 = 236. As a percentage NO3 is 124/236 = 52.5% NO3
For KNO3 is is a bit more straight forward K = 39 and NO3 = 14 + (3*16) = 72. KNO3 RMM = 101 so NO3 is ~ 71%.

To get to "Glasswalker's" 1.3 times as much calcium nitrate tetrahydrate you just divide 71/53 ~ 1.35.

cheers Darrel

 

[GlassWalker]

I didn't save my working, but I factored in density to present it by volume, since the original amounts were given in tsp not g.

 

[Zak Rafik]

Hi everyone,
Thanks for all your answers. Appreciate it very much 🙂

You do have a potassium source, since it comes with the phosphate. The only possible caution is you will have much less potassium than if you had potassium nitrate. You could use potassium sulphate to boost the potassium.

Clive :
As mentioned by GlassWalker, what is the quantity of potassium sulphate ( in gram or tsp) do I need to add to the mix so that there is enough of potassium or is the Potassium Phosphate that came with the kit is enough?

Just for my knowledge, can one overdose potassium. Are there any side effects?

Also I have seen posts where it mentioned that one can dose EI for Macronutrients and as for Micronutrients, one can use Easy Life's Profito.
Wouldn't this lead to double dose of certain minerals or over fertilization ?

http://www.aquariumplantfood.co.uk/fertilisers/profito-500ml.html ( the webite link for information about Profito only)

Best Regards
Raffik

 

[dw1305]

Hi all,
KNO3 has 39% K, so you need to add quite a lot of KH2PO4 to make up for the short fall. As a general rule plants need a lot more nitrogen (N) and potassium (K) than they do phosphorus (P), so you can either over dose KH2PO4, or you can dose at the recommended rate and buy another K source like potassium chloride (KCl) or potassium sulphate (K2SO4).

To work out how much you need it is back to the same sort of calculation RAM K = 39, S = 32, P = 31, Cl = 35.5.

For K2SO4 you have (39*2) + 32 + (4*16) = 78 + 32 + 64 = RMM = 174, % K = 78/174 ~ 45% K.

As 45% K and 39% K are similar ball park figures you can substitute the amount of KNO3 you would have added with the same amount of K2SO4. In that way you still have the same addition of P, and instead of getting both K+ and NO3- from potassium nitrate, you've got NO3- from calcium nitrate tetrahydrate, and K+ from potassium sulphate. Once they are all ions it doesn't matter where they came from, and the Ca++ and SO4-- ions are relatively irrelevant (both Ca and S are essential plant nutrients, but plants don't require very much of them).

cheers Darrel

 

[ceg4048]

what is the quantity of potassium sulphate ( in gram or tsp) do I need to add to the mix so that there is enough of potassium or is the Potassium Phosphate that came with the kit is enough?

Well, if you're an over-the-top looney like me, who doses 10ppm per week of KH2PO4, you''d come near to the target K+, but if you are normal then you'll probably want to add some K2SO4.

I'll ignore the K+ contribution of KH2PO4 just to simplify the calculation and also will make the assumption that the tank is 250L (in real life there is about 20% less water in the tank, but again, I'll ignore that because it's easy to adjust the dosing).

Target ranges for K+ are very wide, anywhere between 15ppm-30ppm per week. We'll target the low end, knowing that the KH2PO4 and the reduced volume will raise the concentration and will take care of us.

K2SO4 is roughly 45% by weight K+.
So, to figure out how much weight (Xmg) per week of the K2SO4 we need to achieve 15mg/L of only the K+ portion just use a simple equation:

0.45Xmg / 250L = 15mg/L

Xmg = (15)*(250)/(0.45)

Xmg = 8333

So, adding 8333mg (8.3 gram or about 1.3 teaspoons) of K2SO4 per week gets us well above the minimum requirements, all things considered.

Again, I don't really do mixes for large tanks. It's annoying trying to figure out how much people use and how many doses the bottle holds for each person. Every tank has a different size.

According to the instructions, your mix is dosed at 10ml per 50L, so each dose is 25ml, which means there are about 20 doses in 500ml. If dose 3 times per week then that means there are about 6.5 weeks worth of dosing.

So just multiply 1.3 teaspoons by 6.5 which gives you about 8 teaspoons added to the mix.

Just for my knowledge, can one overdose potassium. Are there any side effects?

No. This is one more thing not to worry about.

Also I have seen posts where it mentioned that one can dose EI for Macronutrients and as for Micronutrients, one can use Easy Life's Profito.
Wouldn't this lead to double dose of certain minerals or over fertilization ?

Who cares? I triple, quadruple and even quintuple over fertilization all the time. You really need to stop worrying about this.

Are you using that fancy ADA Amazonia substrate? Did you realize it has the equivalent of 100X EI levels of fertilization? Get over it, quickly.

Cheers,

 

[Zak Rafik]

Hi Clive
Just a quick note. The volume for my tank according to it's dimension is 315 liters.

After I put in the substrate and all the hard scape, I carefully measured the amount of water I poured into the tank. That's when I found out that it's actually 256 liters.

I'll study all the info given and reply.
Oh! And by the way Clive, just a side note, I almost failed my chemistry exam in school. Now you know what level you'r dealing with.
Thanks and cheers. 🙂

 

[Zak Rafik]

Hi Clive

I managed to get Potassium Sulphate (98% pure) locally from a hydroponics dealer.


So I have decide to dose according to the calculation which you provided me.

The only question I have is that in many online converters, it says that 8.3grams is about 1.75 teaspoons. Can you please clarify this for me.


Also I have attached the label of the Potassium Sulphate which I have bought. Is the grade ok of IE?



From the same supplier, I got to know that he has Potassium Nitrate but mixed in liquid form. I have attached the photo of the label for your reference.

If in the future I were to use this what quantity do I use and how to use this.

Hope you can enlighten me on this. 🙂


And one more last thing, do I have to mix and keep the Calcium Nitrate separately from the rest fo the macro as informed by member GlassWalker or I can just mix all macros together with no worries?


Apologize for many questions asked.
Cheers
Raffik


http://i1295.photobucket.com/albums/b631/Zak_Rafik/photo2_zpsc3bafdcc.jpg


http://i1295.photobucket.com/albums/b631/Zak_Rafik/photo1_zpsb880f267.jpg

 

[ceg4048]

Raffik, the images don't work.

The only question I have is that in many online converters, it says that 8.3grams is about 1.75 teaspoons

Yeah, maybe. I guess it depends on the spoon. Whatever, it just doesn't matter. If you want to add more then add more. If you don't want to add more then don't. As I've mentioned many times before, and what you need to grasp, is that with this scheme, we are presenting an infinite concentration of nutrients to the plants (from their point of view). It's almost 20X greater K concentration and 100X less expensive than the Brighty K you are using now. It would take about 60 pumps per week of Brighty K to obtain the same K level with this mix - and you're making up a 6 week supply - that's about 360 pumps. At this level of dosing a few teaspoons will not make any difference. Keep thinking about these numbers until it sinks into your subconscious.

Is the grade ok

Any grade is OK. Get whatever grade you find cheapest and most convenient.

From the same supplier, I got to know that he has Potassium Nitrate but mixed in liquid form. I have attached the photo of the label for your reference.

Yeah, if you can fix the image problem or record the details we can have a closer look.
Water can also be boiled/evaporated, leaving behind the dry salt. That's always a clever thing to do if you ever want to find out if you're being ripped off, and it also the reason you should always be suspicious of liquid ferts.

And one more last thing, do I have to mix and keep the Calcium Nitrate separately from the rest fo the macro as informed by member GlassWalker or I can just mix all macros together with no worries?

It's difficult to predict whether reaction will take place with a mix of all these things.

If it is the case then it's better that it happens inside your bottle, because really, the reaction would precipitate out Calcium, which is not a big problem, and Phosphate, which although is a problem, you can always just filter the liquid and add more Potassium Phosphate to it. The result of the reaction between Calcium Nitrate ans Potassium Phosphate is Calcium Phosphate (as a solid) and Potassium Nitrate (as a liquid), if that's actually the reaction that takes place. The type of Phosphate salt itself will determine what kind of reaction may take place.

If the precipitate is a Calcium Sulfate, then this is fine also because this means you haven't lost any Phosphate.

There is no need to worry about this too much. Mix them and look at the results the next day. If there is a precipitate, assume it's Phosphate and just add another teaspoon of Potassium Phosphate, or add them on separate days and see if they precipitate in the tank. Whatever precipitate occurs then just add more Potassium Phosphate either directly to the tank or to the mix.

Alternatively, a better idea would be to withhold the Potassium Phosphate and mix the Calcium Nitrate with the rest of the salt mix. Then you'd know that any precipitate would be a Sulfate precipitate, which is no big deal. Filter the mix and then add the Potassium Phosphate.

Not a very neat or clean answer, I know, but that's just how it goes.

This is another reason mixes are annoying.

Cheers,

 

[Zak Rafik]

Opps! Photobucket seems to acting up.
Ok the link is below. Hope it works. Cheers.

http://i1295.photobucket.com/albums/b631/Zak_Rafik/photo2_zpsc3bafdcc.jpg

http://i1295.photobucket.com/albums/b631/Zak_Rafik/photo1_zpsb880f267.jpg

 

[Zak Rafik]

It's almost 20X greater K concentration and 100X less expensive than the Brighty K you are using now. It would take about 60 pumps per week of Brighty K to obtain the same K level with this mix - and you're making up a 6 week supply - that's about 360 pumps.

Clive it's true. I bought ADA Brighty K 500ml and its about to finish, only after using it for 32 days. If I buy just two bottles of Brighty K alone, for that same amount of money, I can buy one and a half years' worth of complete fertilizers using the EI method.!😱

But I guess liquid fertilizers will always be popular due to the main reason that the companies advertise strongly and the ease of use. The instruction to use are non technical and in layman's language. There is no learning curve associated with it but all this comes at a high price of course.

When I read about EI dosing initially, I kind of got turned off due to all that calculation, purity grade and experimenting involved.
It was only after I got to know about EI dosing from aquariumplantfood.co.uk, that i was confident of using EI fertilization and not to mention the many useful posts from fellow members ( especially yours) about EI dosing on this wonderful forum.

Anyway please take a look at the Potassium Nitrate in liquid form. If it's going to be simple, I can use this Potassium Nitrate ( liquid form) instead of Calcium Nitrate and inturn not use Potassium Sulfate at all. Hopefully a less bewildering method.

Cheers and have a wonderful day.
Raffik

 

[ceg4048]

OK, I can see the images now.
It's about what I imagined, 5% Potassium Nitrate and 95% water...

So yes, you can use this, no question, which will greatly simplify your mix and will eliminate the need for the Potash Sulfate and Calcium Nitrate.

The only minor complication here is that there is so much water. Looking at the package content, you'll want to use about 25ml per week. As I mentioned before, your 500ml bottle standard mix would be a 6.5 week supply. For this product 6.5*25ml = 163ml, so to get around this just combine 163ml of this nitrate product with 337ml of tap water plus the rest of the salts and call it good. That will give you 20ppm K (plus K from KH2PO4) and 30ppm NO3 per week.

If the product is expensive then you can easily get by using 30% less (i.e 115ml + 385ml of tap water + rest of salts).
That will give you 14ppm K (plus K from KH2PO4) and 20ppm NO3 per week.

Cheers,

 

[Zak Rafik]

Fantastic news from you. Thanks.🙂
I called up the supplier and he can make the mix for me. He'll also take back the Potassium Sulphate.

One bottle of liquid Potassium Nitrate will last for 5 months going by your calculation of 25ml per week. One bottle of this product costs less that half of ADA's Brighty K which last for 1 month.

Once I get all the minerals ready, I'll post again.

Cheers and good day.
Raffik

 

[Zak Rafik]

Hi everyone,
Hi Clive

Ok, I managed to get Potassium Nitrate (in liquid form). It's a 1 liter mix. The price was even cheaper than what I expected it to be. 🙂

For the price of a 500ml of Ada's Brighty K ( which lasts for 1 month), I can have 4 liters of Potassium Nitrate ( which will last for 3 years and 3 months!!!!)

Starting tomorrow, I'll will does as per your last post.

I have noticed some Green Spot Algae on the glass and rocks and I have seen on PlantedTankUK YouTube channel, that Potassium Phosphate will treat this algae.
Can you inform how much extra to add for this mineral?

Also I have notice that my mid ground plant Staurogyne Repens are having dark vein but the rest of the leaf tissue are slightly yellowish. Is this due to Magnesium deficiency?

If so, then I curious to know, what kind of frets does Ada Amazonia aqua soil exactly contains. Since there is Potassium and Magnesium shortage in my tank now.

http://i1295.photobucket.com/albums...9-C5F9-4DE4-89B1-56DFC761191C_zpsydu0hqlg.jpg

Thank you very much and Cheers
Raffik

 

[ceg4048]

I have noticed some Green Spot Algae on the glass and rocks and I have seen on PlantedTankUK YouTube channel, that Potassium Phosphate will treat this algae.
Can you inform how much extra to add for this mineral?

Hi Raffik,
Glad you were able to get the KNO3 at an acceptable price.

I'd prefer that you stop thinking in terms of "treating algae". Algae is not a disease. It is a predator and it preys on the weak. It's so very important to change your mindset and think along these terms. It may seem like a trivial point, but it actually a very important point of view because it will help you to perform a more accurate analysis of problems that occur in your tank. If it helps, think of algae as hyenas or as a pack of wild dogs and think of the plants as deer antelope. If the deer are healthy they can resist the attention of, and escape from the hyenas. If the deer are sick then they fall prey to the advance of any hungry predator.

So what you are doing in your tank is that you are finding effective methods of treating malnutrition. That makes the plants healthy and allows them to avoid falling victim to the algae. When you think along these terms it will make it much easier to see the path.

Green Spot algae attacks occur due malnutrition caused by any combination of poor PO4 and poor CO2. The combination could be, for example a minor PO4 deficiency + a major CO2 deficiency, or a minor CO2 deficiency + a major PO4 deficiency.

Because it can occur due to multiple variations of two missing items it's a little bit more difficult to troubleshoot than something like hair algae, which is only ever due to poor CO2.

So it's very easy to just add more PO4, like twice as much and to see if that strengthens the plant, however, if you have other symptoms in the tank of poor CO2, or, if you already have a known high PO4 content, such as an enriched sediment, then that gives you a strong indication that the GSA may be more closely related in that case to the "major poor CO2" end of the spectrum.

Newly purchased Amazonia is very high in NPK, so I would not expect to encounter a low PO4 scenario when using this unless the sediment is a few years old and perhaps has had it's once high NPK content exhausted.

Cheers,

 

[Zak Rafik]

something like hair algae, which is only ever due to poor CO2.

Hi Clive
I do have hair algae in the tank but just like GSA, its in 3 to 4 small spots ( especially on the carpet plants). Taking into consideration the age of my tank and the enriched aqua soil used, I think i can safely come to the conclusion that it all boils down to poor Co2.
I'm really confused with this Co2 matter to be honest.😕

I have a 3 litres Co2 cylinder and have used it for 38 days till today . I can't even count the bubbles in the bubble counter, its that fast.
Co2 solenoid has been set to be on 3 hours before lights on.
The 3 ltr Co2 cylinder will finish by tomorrow.

I'm using an inline Co2 diffuser with hope that there will be minimal gas loss into the air.
Now I have moved the diffuser to the intake pipe before the canister filter hoping for even more Co2 to dissolve.

To create a better flow I have switched to a bigger capacity filter (Eheim 2080) and have a powerhead to create a further flow in the tank.

I'm now perplexed and at a total loss as to what to do next.

Should I :
up the Co2 gas further?
change to an intank diffuser?
????

Take care.
Raffik

 

[ceg4048]

Raffik,
There's no need to be confused. Your expectations of how difficult a task it is to supply adequate CO2 were simply overly optimistic based on the good luck you've had up to now. You have to remember that the tank size is over 300L. Everybody is proud to say how many ppm of CO2 they have, but do they actually know what that means? In your case it means that for every kilogram (or liter) of water in your 300L tank, you need to dissolve 9 grams of a gas which weighs practically nothing. Imagine how much gas you must need to achieve that, especially when the gas is accelerating out of the tank and especially when the water temperatures are at tropical levels. And you are using a puny 3L bottle of gas? I'm shocked that the gas lasted as long as 38 days. That tells me you're not using enough gas.

When your tank was young and you only had a few dozen grams of plant matter, it was easy to supply the necessary levels of Carbon, but as the plant mass increases then each plant consumes more and more grams of CO2. The kilograms of Carbon that you have already fed to the plants has turned into plant mass. The CO2 you have been added is reflected in the weight of the plant mass you are looking at.

Now you have to feed that additional mass of plants dozens of times more milligrams of CO2 than you did a month ago. The plants in effect becomes a kind of "Black Hole" for nutrients/CO2. Their appetite becomes insatiable. If you ever get a chance, rent the movie "Little Shop of Horrors". It's a bout a guy who buys a small plant and has to keep feeding it more and more as it grows. Pretty soon, the plant is bigger than he is.

So stop thinking about CO2 in terms of how much you open a needle valve or of how many buttons you pressed. It is mass and fuel for hungry mouths, in almost the same way as the coal being fed to a locomotive steam engine. The things we admire the most in plants when we look at them or imagine how they should look is simply a reflection of nutrients/CO2.

I don't even recall the level of lighting in the tank. You probably have posted it somewhere, but my guess is that it's reasonably high. You're living in a warm place so the tank water temperature is high. So the solubility of the gas is much lower than some other tank located in a cooler place.

The quickest way to take a deep breath is to lower the demand for CO2 and lower the loss rate of CO2. If you can lower the temperature by even a few degrees you can improve the gas solubility by 15% to 20%. That also lowers the metabolism of the plants but also lowers the metabolism of algae. Also, always consider reducing the intensity of the light because light is at the very top of the demand chain.

You can even do what I call a "soft blackout", where the light and CO2 is turned off for a few days.

You can also lower demand by reducing the plant mass. Less hungry mouths means less demand for CO2, so a heavy trim can make more CO2 available.

If the tank is uncovered you can temporarily cover it with acrylic or glass to reduce the gas escape rate from the surface.

If you have a lot of surface disturbence that also accelerates the gas escape rate. Reduce the disturbance to help reduce the escape rate.

You just have to keep working at it, looking at the distribution to ensure it's the best it can be, increasing the injection rate as much as can be tolerated by the fish and then backing off from there. Using liquid carbon at least in the short term. Now that you have saved money on ferts, maybe you can afford to dose liquid carbon in that size tank, at least temporarily if it's available at your location.

You definitely will need a lot heavier gas cylinder. I would only use a 3L cylinder on a nano. Your tank will comfortably swallow a 10Kg CO2 cylinder. That should last about 6 weeks. Bubble rates are irrelevant in a tank that size bombarded with megatons of light. I just listen to the tone of the high pitched squeal as the gas comes screaming through the plumbing. In my case a high F sharp is about right. At lower tones, such as F or E, I get hair algae on the very top leaves.

Hope this helps...

Cheers,