# Help me do the math, please...



## nasfish (Sep 26, 2005)

hi,

over here, where i come from, it is difficult to get dry ferts such as KNO3, K2SO4 etc. The only alternative is commercially available liquid ferts. So, I bought this liquid ferts with the following dosing instruction...

10ml/70liter provide 3.5mg/l NO3, 0.5mg/l PO4 and 2.5mg/l K

So how much should I dose for 220 liter heavily planted,high light,high CO2 tank? and what if I would like to dose 3 times a week...how much per dose?

Feedback really appreciated.

Thanks


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## dennis (Mar 1, 2004)

30 ml in your 220liter tank would be about the same concentration of ferts. In your high light, heavily planted and CO2 injected tank I would dose a 4x(120ml in your case) dose 3 times a week. This would give you 14mg/l NO3, 2mg/l PO4, 10mg/l K with each dose. Do that 3 times a week equals 42:6:30 N:K.

I feel that is a bit high in PO4 in realtion to NO3 bit if that is all you have to work with... I would try to find an additional source of NO3 to help balance that out if you can. You should be fine though with that ratio, just feed you fish enthusiastically to add a bit more NO3 weekly. Make sure you are changing 50%+ water each week to help prevent buildup of PO4. If you could find an additional source of NO3, I would add a 2x (60ml for your tank)dose of your fert solution plus an additional 3-4mg/l NO3.

Good luck


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## nasfish (Sep 26, 2005)

thanks dennis, a quick response and a great forum..

so let me get this straight. dose 40ml 3 times a week? is that what are you saying?

Thanks


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## dennis (Mar 1, 2004)

Sorry, I realize my response was a bit blundering. Let me try that again in different way....

I will assume you will use this as your sole macronutrient source. I will also assume you have micronutrients from another source. Lastly, I will assume your tank is 210 l since that makes for easy math and besides, you probably loose more than 10l with substrate, rocks, etc....

I will base this on the NO3 since adding enough NO3 will give you enough PO4 and K. So: 10ml/70l = 3.5mg/l NO3. 210/70=3 so 3*10ml=30ml to equal 3.5mg/l in 210l tank. I would dose 10mg/l NO3, 3 times a week so 10/3.5(per dose)= 2.87*30ml=85.7ml.

To check that, 10ml/70l=3.5mg/l NO3. So, 1ml/70l=.35mg/l (210/70=3) So, 1ml/210l=.12mg/l NO3....10mg/l/.12mg/l=83.3ml/210l=10mg/l NO3 Pretty close

You should dose 85 ml to your 210l tank to get 10mg/l NO3 per dose. I would dose that 3 times a week.

Sorry for all the / and = signs and very sorry to e so off before. I forgot to finish my thought in my earlier post. Glad you questioned me.


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## hoppycalif (Apr 7, 2005)

I think Dennis nailed it the second time! You might find some stump remover there which you can question the manufacturer about to see if it is pure KNO3 like we have. That would be a second source of nitrates. (and a new round of calculations!)


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## nasfish (Sep 26, 2005)

Thanks dennis,

Yes, I will use use this as my sole macronutrient source. For micronutrients, it is from another source.

If i were to dose 85ml, 3 times a week, 500ml bottle will only lasted 2 weeks...now i know why the liquid fert is the cheapest here.. 
85ml to provide 10mg/l NO3 per dose. But i am targeting about 7mg/l NO3 per dose. This is to follow the EI dosing guide :

From EI Dosing Guide Above
40-60 Gallon Aquariums
+/- 1/2 tsp KN03 3x a week
+/- 1/8 tsp KH2P04 3x a week
+/- 1/8 tsp K2S04 3x a week

Using dry ferts (per dose)
1/2 tsp KN03 = 7.05 ppm NO3
1/8 tsp KH2P04 = 1.35 ppm PO4
1/8 tsp K2S04 = 7.12 ppm K (K also from KNO3 & KH2PO4)

Using my only source of ferts available (per dose, 10ml/70liter provide 3.5mg/l NO3, 0.5mg/l PO4, 2.5mg/l K)

So, for my 220 liter(approx 60 US gal, actual water volume) tank, 60ml each dose provide approx 7 mg/l NO3, 1 mg/l PO4, 5 mg/l K as close as EI dosing guide above. 

Am I right?

Thanks again.


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## dennis (Mar 1, 2004)

Your math seems right. Personally I feel that 21ppm NO3 and 3ppm PO4 weekly will cause an increased demand for NO3. You shoudl be fine though...how much light do you have over this tank? What kind of lights are they? Do you CO2 and how much? How heavily planted and what is your fish load like?


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## nasfish (Sep 26, 2005)

Wow a quick response...thanks dennis

Anyway my tank (6 months old) as shown below :









Lighting : 6 X 36w Philips 865/4P PLL, 2 X 36W ADA NA PLL -10-12 hours daily
CO2 : 3 liter tank, maintaining around 25ppm, 10 hours daily
Current Fert : Brighty K 5ml daily, Brigthy Step 2, 10ml 3 times a week, ECA 10 drops 3 times a week.

From the current fert, you will see there are no macronutrients dose to this tank except for K from Brigthy K. And I don't want to continue using Brigthy K either. So for my macronutrients, perhaps I can use from other source such as this newly bought liquid fert, with puzzling dosing instruction.

I have mild BGA, only at the front, where the subtrate meets the glass at the bottom. I am thinking of increasing NO3. Current NO3 is somewhere between 12 to 15ppm throughout the week. But the test kit is not always accurate...also some hygro at the back showing some deficiencies too..

Thanks


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## dennis (Mar 1, 2004)

Increasing you NO3 should help the BGA, which is usuallya sign of a real dirty aquarium and/or low NO3. You tank looks clean and pretty healthy (attractive also, nice job) but the branching or the Ludwigia cuba tells me either you need more CO2 or you let the plant grow out of the water Increasing you CO2 would also increase NO3 consumption, as would switching to a fert schedule that includes lots of PO4. 

Bottom line in my opinion, try raising the CO2 a little adn find a way to add more NO3 than this will give you.. Good luck and I envy your Eriocalion sp in the midground.


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## nasfish (Sep 26, 2005)

Thanks again dennis,

Actually that is P. Stellata, narrow leaf, started to branch out about 2 weeks ago. I was amaze because I never dose any macronutrients, except for K from Brighty K in this 6 months until I get mild BGA at the front. The BGA just under the substrate surface. I do 50% water change weekly, I do feed my fish 2 times daily. Also, recently I have increase the water flow by installing a small pump at back, pointing to the front. I will increase my CO2 as you suggested. Usually at the end of the photoperiod, a lot of pearling in this tank.

I am lucky to get the Eriocaulon sp. Cinereum, a beautiful plant. Initially I have two of this plant, manage to propagate into 9 baby plant. Now it is growing great. Soon I will have many more!..

Thanks


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## dennis (Mar 1, 2004)

Do you know why your P stellata stunted? Did the growth tip grow out of the water? I find that my old stems would branch like that if they grew out of the water or the tank was low on CO2. I am wondering what your observations are? Did the growth tip stunt before the branches formed?


I assume you are using the ADA substrate? I guess that explains the months of good growth w/o macronutrient additions.


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## nasfish (Sep 26, 2005)

Yes I am using ADA substrate.

I am not sure why my P. Stellata stunted and started to branch out. My guess will be the sudden bottom out of my macronutrients. 2 weeks ago I do about 2 times 50% water change in a week. First time after top up the aqua soil at the back right corner. Second time to do minor rescaping and replanting. Maybe the nutrient levels change too fast.

Yes, the growth tip stunted before the branches formed. My CO2 injection always the same (increase actually, after more plants). I do found out that P Stellata don't like the increase water flow though.

I am thinking to trim the tops and leave the bottom in place. It will produce many sideshoots, making it bushier, just above the driftwood...

Thanks


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