I'll try this...

Thanks

--
Craig Brye
University of Phoenix Online

" wrote in message
m...
75 gal. tank
220 watts of CF lighting suspended about 3-4" above the water line
UV Sterilizer
CO2 injected via pressurized bottle
KH 3-4 ppm
GH 5 ppm
pH 6.5
Temp. 75 degrees F
Nitrates around 6-11 ppm fairly steadily
Phosphates are around 0.1 ppm
I also add trace elements, etc.

I don't have any algae besides the normal "non-problematic" algae such
as the spot algae on the glass from time to time.

Add more PO4, at least 0.5ppm.Your spot algae will go away if the CO2
is also good.

I assume you mean 3-4KH degrees, not 3-4ppm.

You can search on this site, the APD and other places for my comments
on Fe and uptake and testing. I will tell you to toss your kit. It
will not ell you what you need to know.

For your tank you need to resolve how much traces you need in this
manner:
Make sure other things are non limiting, the CO2, the NO3, GH, K+,
PO4(you need to add this) and then add 15mls of flourish or TMG 3x a
week.
That is close to the max uptake needs of plants at 330w of light.

From therer, back slowly off the dosing, do each change over 3 weeks,
so the following 3 week block, do only 12mls 3x a week etc.

Once plant growth starts looking so-so, then you have hit the minmum.

No kit required.
But you will note a much improved tank if you add PO4, you will also
see the NO3 uptake rate increase 2-5x.

Dose the traces one day and the next the macros.

Plant % of Fe means adding very small amounts, perhaps 0.06ppm a day
is plenty, but experience shows we need to add more than this.
Fe complexes with water(10 or so diferent types), is oxidized, and can
complex with a dozen or more organic compounds.

A test kit will not tell you how much is bioavailable to the plant.


Regards,
Tom Barr


The question I have is on Fe uptake. I was wondering how much Fe plants
can use over the course of a day or two. I seem to be adding a lot of
trace elements, and the Fe seems to disappear almost within a day. I've
been trying to measure the amount in the water to get a general idea,
but I can't register any a day after I've added some. I've been putting
anywhere from 1/4 to 1/2 tsp. of dry trace mixture into a milk jug of
water and dumping the entire mixture in.

I've heard two different sides of the UV sterilizer issue, and have a
hard time believing it would corrupt the traces that quick. The trace
mix (dry form) is about 2 years old, and I wonder if that is playing a
part. Maybe the test kit is bad, although this doesn't seem to be the
case since it will measure it one day but not the next. The plants are
doing ok, but growth seems like it could be better (I've seen better in
previous tanks). I have a hard time getting the robust growth without
the leaves getting full of some minor spot algae. The Bacopa Carolinia
seems to be growing slow as well.

Any ideas on this?

Thanks,