Re: Aquatic Plants Digest V2 #275
> From: MMacG1167 at aol_com
> Date: Wed, 23 Oct 1996 17:04:00 -0400
> Subject: Red Ludwigia questions
> I have some red ludwigia in a 55 gal tank. It grows perfectly well, but I've
> been using it as a background plant and as it grows up towards the surface it
> begins to put out a lot of roots from the stems. Some of them are very hairy
> and brown and others are white colored shoots, and it detracts from the
> appearance of the plant. I tried clipping a lot of them off once but they
> just grew back, so I assume that there's no way of preventing this from
> happening when it is left to grow tall. I could move them forward from the
> back and keep them shorter, although a 55 gal tank is so narrow (12 or 13"
> wide) this might be a problem (since I don't want it in the foregound). How
> do other people keep ludwigia? Does anyone have any thoughts or solutions to
This is a common occurrence with several stem-type plants. I don't think
there is much that one can do to change the basic nature of this plant.
I think most people(myself included here) just learn to accept it.
> From: Christopher.Holloway at hr-m_b-m.defence.gov.au
> Date: 24 Oct 96 10:59:47 +0000
> Subject: PMDD
> I have been trying to get a hydroponics shop to mix me up a batch. I
> have also been talking to Paul Sears and Pat Bowerman about the actual
> chemistry mixture, and I have also been talking to James Wong. Thanks
> to all three for their help and their patience.
> Not being a chemist I have found the PMDD recipe to be fairly
> confusing. It transpires from several exchanges that the percentages
> of trace metals listed as part of the PMDD recipe do not refer to the
> chelated metal complexes themselves; rather, I THINK they refer to the
> amount of metal delivered by the chelated complex once the complex is
> 'active' in solution.
> This is to say that if you get a TE mix recipe that calls for 7% Fe
> (as the PMDD recipe does), and you make up a mix that contains 7% Fe
> chelate, you don't actually end up with 7% Fe in the water and
> available to the plants. You actually end up with a considerable
> anmount less - as Pat explained it, you end up with about 1.5% Fe
> available to the plants.
I don't recall mentioning any percentage that would be available to the
I did talk about the recommended percentage for the trace element mix.
I think that you guys are making this more complicated than it need be.
For me, the hard part was in finding the right trace element mix. Once
this was accomplished, the rest was a snap. I believe that if you dig
through the archives; you will find several mentions of potential
sources for the trace element mix.
> From: "Williams, Rochelle - DCSPIM" <williaro at ftmcphsn-emh1_army.mil>
> Date: Wed, 23 Oct 1996 17:44:00 -0400
> Subject: Of fish loads and nitrites
> Please, someone check my logic and correct as necessary. Plants need
> one of the 3 parts of the nitrogen cycle as a macronutrient. There are
> other macro- and micronutrients (along with light) which must be present
> for growth. The proper balance of macro- and micronutrients will give
> maximum growth. If one or more nutrients are missing, plant growth is
> not optimized. Test kits can read macronutrients and some of the
> micronutrients. So if the test kit reads zero, then the plants are
> using all of that nutrient, leaving zero in the water, and have not
> reached the optimum level of growth. If the test kit detects anything,
> then a sufficient level of that nutrient is available.
> OK, if all of that is right, here's the big questions...Why are planted
> tanks maintained at a LOW BIOLOAD? My tank is nitrogen deficient, the
> test kits have read zero for nitrates and nitrites since its creation
> over 6 months ago. The plants are growing but I'm having problems with
> red algae. Yes, I'm a firm believer in Neil Franks' article on
> controlling red algae. The local water is high in Phosphates and I
> don't want to use Phos-Zorb or RO water to lower it. I prefer the
> plants use it. Based on all the postings and web pages on the subject,
> I need to optimize the PMDD but many people say DON'T ADD chemical
> NITROGEN. The phosphate and lights are causing the algae problems...but
> rather than decreasing the lights or chemically filtering the water, I
> want to optimize the other nutrients and have the plants give maximum
> growth and use it up that way. <Die, algae, die!>
Okay, who says don't add nitrates to your water? potassium nitrate is
one of the cornerstones of the PMDD regimine. If you have read Paul
Sears and Kevin Conlin's article on controlling algae, you would surely
feel like you needed more nitrates in your tank. I'm on thin ice here,
but I believe that they would tell you that your plants will not be able
to utilize more phosphate if they are currently nitrogen limited.
There is also every reason to believe that adding more fish might
actually make your problem worse. I believe that you would be increasing
your phosphate level, without increasing trace elements. Sure, your
nitrate level may increase some too, but IMO this is not the solution to
> So, I want to add more fish to the tank, until I get some kind of
> reading on the nitrate or nitrite test kits.
I don't think so.