Nutrient Levels - Planted Tanks

[Thor]

I am not able to find information on the macro and micro nutrient levels to be used for plant tanks. As far as I know:

Carbon : CO2 = 15~25 ppm
Nitrogen : NO3 = 5~10 ppm
Phosphorus : PO4 = 0.5~1 ppm
Potassium : K = 20 ppm
Magnesium : Mg = 5~10 ppm
Calcium : Ca = ?

Are these correct? Can we use GH measurement to determine Ca and Mg as I do not have test kits for these right now.

[vinz]

Some minor corrections...

CO2 - some say up to 30ppm. I'm doing that.
K - Up to 30ppm too.
Ca:Mg (ratio) - I've seen various recommendations from 2:1 up to 4:1. Take the middle rd.

Yep, GH is indicative of Mg and Ca levels... but you can't tell how much of the GH is Mg and how much is Ca. There are no test kits for Mg and Ca in freshwater. There are marine test kits for them.

Click here for of Tom Barr's recommendations.

[Thor]

Thanks.

[illumbomb]

Hi,

Is it advisable for me to add MgSO4 even if I never observe any Mg deficiency? I am adding something like 4ppm of Mg per week, doing a 30% water change fortnightly.

[DEA]

i believe it's ok
i dose all the time, relying on biological means of algae removal to keep the small excess in check
like vinz says, it's a recommended value
i don't see how anyone can say for sure what levels of what nutrients should be in your tank without actually doing long term testing on your SPECIFIC tank
so, just trust your plants to kill off the algae in the long run, is what i practice

[jameshoftiezer]

I have recently lowered the MgH20 that I have been adding because of perceived interference with Ca uptake, but I was dosing my trace/Mg mixture way too high anyway trying to get ready for a contest.

Most people I know trace the micro nutrient using Fe. They dose the trace (as below) until the Fe is at their target point. I dose it bases on visual indicators, but have recently realized this is not perfect as the plants I used color based on NO3 as well.

Iron 7%
Mn 2 %
Zn .40 %
Boron 1.3 %
Copper .10 %
Mo 1.19 %
Na .57 %

[illumbomb]

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On 4/28/2003 12:35:33 AM

I have recently lowered the MgH20 that I have been adding because of perceived interference with Ca uptake, but I was dosing my trace/Mg mixture way too high anyway trying to get ready for a contest.
----------------

Hmmmm, as I posted in another thread, I am experiencing Ca deficiency after trying out dosing with chemicals for the past 2 weeks.... I am adding 5ppm/week Mg although I don't have any Mg deficiency... Furthermore, I have coral chips mixed with my gravel.

How to know whether the Mg is affecting the Ca or not???

[naturetan]

illumbomb, I'm also experiencing what you've seen. But this deficiency might not be due to Ca/Mg problem. You may read this discussion for more details.

Currently, I'm reducing my total K dose to about 10-20ppm, and start increasing GH for Ca & Mg. I've dose everything except NO3, which I'm going to buy tomorrow to dose. Would suggest you to do so if your tank is high light with low bioload, since lack of any nutrient can cause all sorts of unpredictable deficiency.

[vinz]

Over the last few months, I've had first Ca deficiency then GH went sky high and Mg deficiency (was really hard to tell) set in. I tried dosing some Mg and the plants responded positively, but still weren't doing very well. After following a few threads on Ca deficiency and K blocking Ca, both here and elsewhere, I decided that I'd just change out 50% water and dose Seachem Equilibrium (consist mainly of Ca, Mg and K with some Fe and Mn) to raise 3dGH. Figured it'll reset the balance somewhat.

Much improvement now. All plants are pearling, including Anubias, Java Fern and Bolbitis. Brown algae has appeared, so I have to fix that now and re-establish a new fert regime.

[naturetan]

My case is quite different. I find my Rotala Macrandra reflect the status of my water condition faster compare to other stems & fern plants. It started with lower leaves rotting. Initially thought it could be N & P deficient, based on Chuck's table. However, I dosed K first, and to my surprise, rotting stop.

Since then, I learnt not to trust the deficiency table from Chuck. Based on this initial case, its invalid. Tom Barr has confirmed my belief too. Now, I've worked according to what the plants need, to give optimum condition for growth. Addition of P give more pearling and lushier growth. Most plants are growing well now without sign of deficiency, except Macrandra.

Still too early to tell after recent dose of Ca/Mg. My GH is now 6. The only sign of improvement recently is Rotala Indica no longer shows sign of distorted or shriveled leaves. Yet to wait for Macrandra to sprout new leaves to tell. Hope the addition of NO3 will complete my cycle of balanced nutrients.