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Re: Nutrients

> I am a relative newbie to aquatic gardening.  I have had a few plants
> growing haphazardly in my 75 gallon for about a year but decided to recently
> take it to the next level with compressed CO2.  I have good lighting and
> good CO2 content as measured by the pH versus KH chart.

Well your almost there then.

> My symptom is that plant growth is currently stunted.  The first week or
> two after I added CO2 plant growth took off.  Now it has resumed a more
> slower pace and some algae is forming on my wisteria.  My theory, based upon
> my reading, is that my aquarium is nutrient limited.  I am now ready to
> start adding nutrients.  The problem is that I am not certain exactly what
> to add in my particular situation.

Okay, do this:
Water change 50% weekly
Add KNO3 1/2 teaspoon after water change and every 3 rd day after(Grant's,
Cooke's brand)
Add K2SO4 3/4 teaspoon weekly(Green All brand)
Add some form of PO4(tap water, KH2PO4, H3PO4 30%) for about .5ppm to
1.0ppm.(I use KH2PO4)
Add TMG or Flourish for the trace mix at 20 mls after water change and 10
mls 2 more times that week. This may be increased if growth is good.

Prune and repeat. Add herbivores(say 4 SAE's at least, bunches of shrimps,
otto cats, snails etc). Keep CO2 at 20-30ppm at all times.
GH/KH should be at least 3 or higher.

> A fews days ago I ran a myriad of tests to try to determine what
> nutrient was limited.  My iron test indicated that no iron was present.  My
> phosphate test indicated that no phosphate was present.  My nitrate test
> indicated 15 ppm.  I have a medium-high fish load.  I have Hagen Plant-Gro
> and Seachem Flourish.  I added 1mL of Flourish.  It is my understanding that
> nutrient levels are tested by testing for the presence of iron.  The next
> day I tested for iron and it was again not measurable.

I add 5mls to a 20 gallon tank 3 times a week. Lately even more.

>  I have hair algae
> which would indicate from what I have read that iron is indeed present.

You can easily get/have hair/BBA algae at 0.00ppm of iron. Algae will
respond _faster_ to nutrient changes than the plants. Do not compare apples
and oranges. Think of the long term effect on the plant, not the short term
algae gain.

> this point I am somewhat confused.  I add Plant-Gro as indicated on the
> label.  The next day I measure for iron and I now have .25 mg/L .  Hair
> algae has increased.  The plants are starting to get a little of that brown
> algae on them, so I suspect the iron may have been too much itself and that
> there is still another nutrient deficiency.  Phosphate is still
> non-detectable.

You have multiple deficiencies going on. Quit guessing and see what your tap
water has in it(NO3 and PO4). If it(the tap) has PO4 then a water change can
add some. But you may need to add it. NO3's will be used up much faster once
the CO2,K, traces and PO4 are taken care of. It takes several things to make
a tank grow well. Just follow it down the line 1-2-3 in order. Light, CO2,
NO3, PO4 and K, traces, do I have enough herbivores?, have I done a water
change lately?, pruning issues?, filter cleanings?, do I have enough plants
in the tank? etc. It gets quite routine after doing it for some time. Water
changes and building the nutrients back up is an excellent method to beat up
on algae. So are blackouts.

> At this point, I assume I have too much iron.

Too much or not enough of something else? Do you add any K+? You should if
you don't.

> Plant growth is not
> occurring, though.  If iron is the metric by which the presence of other
> nutrients is measured, how does that work if I added iron via both Flourish
> and Plant-Gro?  To get the appropriate iron level, should I be adding
> Flourish until that level is reached, or Plant-Gro, or just straight iron,
> or something else?  My research leads me to believe that I can add potassium
> without any fear, so I will get some this weekend and try adding that.

That will help.

>  The
> addition of phosphorus, of which I apparently have none, seems to be a taboo
> item,

And my algae in my tanks is taboo as well. Not so in your tanks. So is it
the cause of algae here? My PO4 has consistently been 1.0ppm or higher for
years. I let it drop but it never gets below .5ppm unless I'm out of town
etc for a week. A few have run it at 1.5 to 2.0+ for extended periods. I
went up to 1.8ppm myself. Plants don't need that much is my rational for

> however, and I am not confident as to what steps I should take there
> either.  Should I be dosing everything at once in only the PMDD ratio or
> should I be trying to add particular nutrients as the plants dictate?
> Any help is appreciated.

Try adding the above routine. Just do it for 3 weeks. You tell me. I don't
need a kit if your tap is decent and you have the above nutrients. It does
work. You should test to see what happens and how fast these nutrients are
being used up though. Watch the NO3 and PO4 and the CO2.

Tom Barr