Re: [APD] Tom Barr's Estimative Index

["S. Hieber" <shieber at yahoo_com>]

--- Andrew McLeod <thefish at theabyssalplain_freeserve.co.uk>

> 
> They seem to imply as little as possible/none. I read one
> answer to someone having algae problems; part of the
> answer was to reduce phosphate levels; the suggested
> maximum was 0.15ppm of phosphate, supposedly because even
> 1ppm of phosphate caused problems.


I believe that a level that low (0.15ppm) will tend to
cause algae problems. I wouldn't think of running my tnaks
that low on phosphate and haven't for years.


> Basically they are of the 'nitrate and phosphate is evil'
> brigade; I'm sure they would probably recommend phosphate
> removers etc.

Having not read the article, I don't know if they are
prescribing for, say, soil underlayment set-ups, where
water column nutrition is not as critical for some plants
or what. But if they caution that phosphate in and of
itself at levels of about 1 ppm or more is an algae maker,
that sounds awfully "old-school." I've never expereinced
any problems with phosphate levels around 1.0 - 1.5 ppm.
But things are touchier if I go much lower.

Try growing plants a few weeks or, better yet, months, each
way, as many of of us have, and decide what works best for
the plants and what works best for the algae. But avoiding
plant nutrition isn't the answer and I'd be surprised if
anyone still preached that way.

> i.e. pre-PMDD day thinking? (please note also that I was
> only shaking my head in 'mild' anger :p )
> What I meant was that when they said 'excessive' they
> would be talking in the >10ppm & >1ppm levels...

10ppm nitrate and 1 ppm ortho-phosphate are good rules of
thumb -- good targets, then fine tune to suit your tank,
plants and maintenance habits. Going over or under doesn't
spoil the game; the numbers are not magic and precise. If
you add lots of CO2, going over can really boost growth, if
that's what you're after. Otoh, I wouldn't want to go much
over thgose targets in a nonCO2 tank unless I was
meticulous about very frequent cleanings ;-) .


> PS how much nitrate do you need to add to get algae? I'm
> sure Tom Barr said he once added 70ppm+ and got none...

Diff folks have diff habits and diff talents and tanks, and
so, diff nees. I can get algae going at 30 ppm and lose the
problem if I fall back to roughly 10 or 15ppm. If it takes
Tom all the way to 70 ppm to grow algae, well, maybe he's
just practicing, I'm sure he could do better if he really
tried ;-)

Have plants, have fun,

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