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Re: Nutrients/test kits and low lighting
- To: <Aquatic-Plants at actwin_com>
- Subject: Re: Nutrients/test kits and low lighting
- From: Thomas Barr <tcbiii at earthlink_net>
- Date: Sat, 12 Jan 2002 21:24:47 -0800
- In-Reply-To: <200201110848.g0B8m7M18764 at actwin_com>
- User-Agent: Microsoft-Outlook-Express-Macintosh-Edition/5.02.2022
Ha! I roped Neil back to the list! I'd celebrate with a cold one but it'll
have to be a Sprite since I don't drink:)
> Tom, An excellent list of all the important ingredients for general plant
> growing purposes. The only things you may have left off are "plant
> density" and "experience."
Well that was _someone_ else's job to address those issues! I just tag the
numbers and them go after other pertinent issues. Can't do it all in one off
the fly post:)
> Of course, lots and or fast growing plants are
> needed for those level of nutrients.
I've pondered this lately. I set up a larger low light tank(CO2, high rich
nutrients, good filter etc) to explore this notion. I do have faster growing
plants(Pearl grass, pennywort, and some crypts). While not exactly fast
growing plants since everything is light limited (54 watts on a 60 gallon
cube at 24inches of depth and 2-3 inch gravel depth) I have found that the
algae is very reduced, more so than the higher lighted tanks. I have not
cleaned the glass for months.
But the point is that the nutrients are rich in the water column. UPTAKE IS
SLOW but the levels are similar to that of the high light tanks. There are
some snails and white cloud minnows, no other critters(hordes of
herbivores). CO2 and nutrients can still benefit the low light tank and that
the dynamic is slowed by the low light vs high light tank.
The notion that a high light tank is needed in order to remove high PO4 is
not quite right. It's removal is _slowed_(plant uptake is slower) but the
occurrence of nuisance algae is also slowed perhaps even more so. You can
still have high levels of nutrients but do not expect them to be removed
nearly as fast as a high light tank.
*I've found some very nice benefits to a low light tank, CO2 enriched tank.
Less water changes(almost like the Walstead method)
Damn near no glass algae of any sort, some trace amounts of hair algae
that's easily removed manually (this tank had no herbivores that did much
maybe 20 small snails).
High PO4 and traces, moderate NO3's.
But more importantly, I would HIGHLY
> suggest the higher end of range of some parameters for the more experienced
> underwater gardener. -- DEFINITELY, lower PO4 levels for the beginner, and
> for folks with the softer water.
Yep, me too.
> Too risky to cause algae to become
> established and for them to not notice that the plants are not responding
> positively before it is too late.
This is where the experience part comes in. In most cases this can be traced
to CO2. I pound that issue every time with good reason. Next you go to NO3
and then to K and traces.
> *Regular and sizeable water changes are recommended - (which you said
> later), and
> - size and frequency increase with higher nutrient dosing.
Amano seems to follow this routine as well. Some Dutch do this but it's due
to all the nutrients being in their tap water, high NO3 and PO4(like mine in
Marin- high PO4 but no NO3).
> *GH should include good balance of Ca and Mg - ~3:1 for softer water,
> higher ratios are OK for harder.
Good point for softer waters.
> *Important to prevent the K from exceeding the suggested range with soft
> water or there can be problems with Ca uptake.
Have you found this to happen and tested the K and Ca ranges? Say low Ca of
30ppm and a high K of 50ppm ? or even ranges 30 and 30? Worth a look.
> *For comparisons to N and P: P is ~1/3 of PO4 and N is ~1/4 of NO3
> *less PO4 is needed in water column for "rooted" plants; especially in
> established tanks which can have a P reserve in a soil/laterite substrate.
Well I came at this from another approach. Most folks used laterite, cables
etc. I used RFUG's which make the substrate inherently "poor" in any
nutrient besides bacterial film(not much nutrient storage). I ran two of
these in soft water years ago. I also took care of a few SF water tanks
which is very soft water(GH/KH 2 or less).
I was able to produce very good plants without much reliance on the
substrate. I became essentially a water column only fertilizer.
At lower lighting, PO4 from the substrate can work but as growth rates
increase.....so does the need for translocation of Fe and PO4 is slow
compared to water column transport. In a number of lower lighting tanks
you'll find nicer colors in part due to this.
> Readers should comment and add other points!
>> Folks with low CO2 will get algae (in this case our indicator
>> preturbation->poor or low CO2 with high light, PO4, NO3 etc all at the
>> preset range except for CO2) and poor plant growth. You need to make sure
>> the other nutrients are in good shape during this period.
> What are the other combinations that will result in algae?
NH4, big trims(massive removal of plant mass-large changes in uptake rate of
the nutrients), disturbances to the substrate, extreme light or too little.
Traces? Namely too little IF the other nutrients are kept in a good range.
I've added 2-3 x the amounts I've said here "just see" but this is in a
harder water tank. I've added a lot to soft water tanks also(say 5 mls 3x a
week at 3 watts a gallon per 20 gallons of tank) with great results
By contrast.....A 20 gallon tank I have with good plant mass, water changes
has gotten 10mls of TMG 3 x a week. I also used Flourish the following week
to see differences. I did add an extra spike of iron with the flourish(2 mls
once a week). That's pretty rich. I have not run this for 3-4 weeks(a good
test timing length IMO) but it is next up. I did not get any problems at the
higher levels and actually a little better growth. My residual dosing is at
5mls 3x a week per 20 gallon.
I ran a NO3 extreme case a few years ago. I ran the NO3 up to 75ppm for 3
weeks. No algae but had low PO4 and lower trace additions. I was worried but
I think I'll try it again with higher traces and PO4's. I'm expect algae for
dinner. I'll try removal/lowering of traces at high NO3's and then low PO4
with high traces. Lastly low PO4/Traces.
Do not try this at home folks! Let me screw things up. I can fix them
easily, many cannot.
I have several tanks, not just one that I run manipulations on. Aberrations
are always suspect. You must run the odd looking ones a few times to be sure
of a possible trend.
Okay the rant is done. I better stop:)