# Fertilizer review



## scuba guy (Feb 10, 2007)

Would someone remind me what each of the macro fertilizers do for plants.

For Example - Nitrogen I know gives the plants leaf mass and green (along with Iron).

What does Potassium do for the plant?
What does Phosphate do for the plant?

Just curious ...


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## Left C (Jun 14, 2005)

Steve Hampton has a good article about the various nutrients: http://www.aquariaplants.com/nutrientsfertilizers.htm

There's also some information about plant deficiencies too: http://www.aquariaplants.com/plantdeficiencies.htm


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## Freemann (Mar 19, 2004)

Check my chart:
http://www.aquaticplantcentral.com/...facts-interactions-deficiencies-excesses.html


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## scuba guy (Feb 10, 2007)

Thank you Freemann !!! This is what I needed!

I have plenty of Nitrate in my aquarium, I add trace micro's every day (Flora-24), my Phosphate comes from my water changes and maintains at .5-1.0ppm, and I add K every water change - not sure the level in the aquarium.

My plants 'look' o.k., but they are not growing ?? especially the Amazons. I get leaf growth - green, lush, but stunted. I am really puzzled since these same plants a few years ago would grow to the top of the tank. Now they are just bushes - gorgeous , but not what I want. My ludwigia is RED...I mean RED - I have never seen it so RED - and the leaves are like saucers - big and firm. Great looking plant. My Tiger Lilies are stunted just like the Amazons. Nice leaves, just very small. It also started out huge.

I have 4 96 watt compact fluorescents on following a diurnal cycle (two of the lamps on for 4 hours during peak day). Plenty of CO2.

So it has just got to be some subtle nutrient ration going on that I have to discover.

Little algae by the way. I would call it normal (no green water at all) - grows on the glass and the Pleco gets it as well as the shrimp.


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## Laith (Sep 4, 2004)

Why not try adding a bit of phosphate and see if things improve over a week or two? You may be surprised...


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## scuba guy (Feb 10, 2007)

Scary .... Fearful of algae. My tapwater has 1.0 ppm - so when I do water changes I just assumed I had plenty of phosphate ...

Test kit yields .5 - 1.0 most of the time.

Should I still go ahead and try?


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## Laith (Sep 4, 2004)

Phosphate does not cause algae unless there is an overall imbalance of nutrients. If you're sure that all the other nutrients (how sure are you of the Nitrate levels? are you adding any?) are adequate, then additional phosphate will not cause algae. If it does, something else is out of balance. I've had PO4 up to 5-6mg/l with no issues.

If you're sure of your NO3 and CO2 levels, you might actually be PO4 limited in your tank. At 0.5mg/l, you may be hitting the error margin of your test kit (calibrated?) and actually have very little PO4, especially towards the period before your next water change.

Start low, perhaps adding 1mg/l of PO4 a week (spread over a week, not all at once) and see what happens after a week or two. I actually add about 4.8mg/l a week but I don't have any PO4 in my tap water.

If you do this, keep an eye on your Nitrates. What often happens is that PO4 added to a PO4 limited tank will rapidly increase the rate of Nitrate uptake so you want to avoid bottoming out on Nitrates!


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## scuba guy (Feb 10, 2007)

Laith - I think you're on to something. I just ordered 'Phosphate' from GW to run your test. I will add a little (1mg/l) or so and start observing.

My Nitrate is rock steady 10 ppm. Nitrate Test kit is calibrated and working great (lots of shaking does the trick).... Perhaps it is the Phosphate that is keeping my Nitrate from getting soaked up. I do have 10 medium sized angels (breeding) who are fed very well (high protein live/frozen critters) - which I am sure is generating lots of NH3/4. Still, I expected the Nitrate to be an issue (maintaining it at a higher level). I have not had to add nitrates in 4 weeks. Perhaps the PO4 is the reason.


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