[APD] comparison of PMDD and Toms method side by side please

["Candy M." <cry_little_sister at hotmail_com>]

Thank you for your response,
I guess you could say I am trying to figure out where my main (55gal) tank 
fits so I can choose a way to treat it.

When I set my tank back up in mid October I did it as I always had with 
sandblast for gravel (used to be texblast) only this time I wanted to keep 
softwater fish instead of a oscar, so I started looking at live plants. I 
found this forum and read tons (very very helpful thank you all.) I spent 
some time looking over plant databases to choose plants that were suitable. 
I scraped the stock hood and built my own canopy which holds 2 shop lights 
4x40watts NO and put 2 "sunshine" bulbs and 2 "aquarium and plant bulbs" in 
it and put it on a 12 hour light cycle with a timer. I got a few plants 
(crypts & water sprite) at walmart (slim pickings) and had my LFS order a 
couple more (very sad looking when they came in some were not the correct 
plant). The LFS does not carry any live plants in stock. At least at walmart 
you can see the plants before you buy them when I order through the LFS you 
pay for and take what ever they get in. I had converted the "city water" 
contents of my tank over to mostly RO water because of the high GH during 
this time.

I added my few plants to the tank, set up a diy CO2 system, and purchased 
the only aquarium plant supplement around here (leaf zone - which is an Fe 
supplement).

As it sits right now I have four Cryptocoryne wendtii, Ceratopteris 
Thalictroides (water sprite), java fern, hornwort, and a few cuttings of 
Bacopa monnieri,  microsword and dwarf sag.
A list member sent me a  few vals and bolbitis, a taller crypt, a cutting of 
Anubias nana,  a tiny piece of x-mas moss most of which are still trying to 
recover from the "bleach treatment" (the xmas moss didn't need bleached)

After the initial acclimation period they are all doing well, the water 
sprite has now become several plants and I have spread it out to fill in the 
lack of other plants, the crypts have stopped melting and are spreading and 
the rest are showing signs of growth at various rates.

I recently added a small ocelot sword, I put it in a small clay pot with a 
mixture of clay, gravel and peat and topped it off with gravel, I figured as 
it grew I would have to move it and there would be less root damage this 
way. I also added 1/3 of a jobe plant spike in the pot and I did not want to 
release the jobe spike into the water column when I move it.

I am trying to figure out where my tank fits in. It will be mostly slow 
growing plants, but even those will do better if properly supplemented. I am 
currently using only 3 of the bulbs (120 watts) over the 55 gal tank since 
the fourth bulb seems to traumatize the neons, Once I have  more of a 
"overhang" to the plants I think they will do ok with all 4 on. The 
substrate is currently all gravel. At some point I want to tear this all 
down and add red art clay and a slight amount of canadian peat since 
laterite is cost prohibitive.

Tank occupants are 6 neons, 6 Harlequin Rasbora, 4 glowlight tetras 
(Hemigrammus bellottii), 3 cory cats, 2 otos, 6 ghost shrimp and a male 
betta who thinks he rules the tank.
I have 1 cory and 5 otos in the quarantine tank to add as soon as they are 
ready. I have been unable to find SAE's and my LFS can not order them. I 
would like to add another 6 neons or cardinals eventually, but don't want to 
overload the tank. I have read enough to make sure I leave room for the 
SAE's if I can ever find them. (the rasboras actually "school" better than 
the neons)

For economic reasons I can not go buy the Flourish line, which is why I am 
trying to use the chemicals directly rather than the logical stepping stones 
you recommend. (Yes I should have probably not started this hobby but I keep 
telling myself that once I get past the initial cost, it is not that 
expensive to maintain)

The wonderful thing about planted tanks is that I wont have to fight spider 
mites which is the bane of growing things outside here. I have all this 
wonderful Texas sunshine but it comes at a cost. I become like a mother hen 
over my outside plants in an effort to keep spider mites from killing them 
without using chemicals.

Planted tanks = no spider mites :)

"Could someone explain in newbie terms what is the main dif between PMDD and
Toms formula, near as I can tell Toms supplements phosphates also where as
the pmdd limits them. I am admittedly a confused planted tank newbie. Sort
of a side by side compare/contrast."

Candy,

I am going to limit myself to giving you the 10000 foot view as I see it.
The PMDD formula is based on the concept of limiting certain nutrients or
nutrient (PO4) to combat algae. While this has proven to work, it also
limits PO4 to the plants which will obviously not benefit from this. Tom
Barr's method instead is based on providing certain amounts and ratios of
nutrients in order to not limit the plant growth in any way. Algae in this
case is "magically" defeated by the plants themselves... I say magically
because, as I'm sure you have read the recent posts on this topic, we are
still not sure what it is that makes the plants win over algae in this
scenario. But as you said, the main difference is the addition of PO4 and
the recommended levels of nutrients. I also feel there is some difference in
the amount of light used in the PMDD paper compared to Tom Barr's regime, if
I'm not mistaken PMDD was conceived and tested in tanks with less light than
the ones Tom Barr's method is most successful in. I may be wrong however,
it's been a while since I read the paper... I think as lighting is increased
and therefore plant growth is sped up, limiting PO4 will cause
greater/faster effects on the plants than it would if plant growth was
slower.

If you are new to all this stuff, as I was coming from a strict history of
low light tanks, I found it easier to not have to worry about finding
chemicals, making mixtures and figuring out concentrations and so forth
initially. I adopted the Tom Barr method, however started off using off the
shelf products. In my case I used the Flourish line (Flourish, Iron,
Potassium, Phosphorus, Nitrogen and Tabs). I had very good results using
these products and switched to the dry chemicals for economic reasons, nothi
ng more. I did not personally find the CSM+B trace mix to be as complete or
effective as Flourish so to date I rely mostly of Flourish for my traces. I
also mix some CSM+B into the trace mix, mostly because I have 5 year supply
of it, at least... I found that by doing this I was able to concentrate on
dosing and finding the ideal levels and ratios that worked best in my tank,
then moved on to "cooking my own".

In the end you have the option of using a few different chemicals or
products for each element, you noted a couple yourself for PO4. I don't
think there is any differences or specific recommendations in one method or
the other as far as which chemicals to use. It's mostly a difference of how
to use them, frequency, suggested levels and other minor differences. Seeing
we have the luxury of having the authors here, I'm sure they will be able to
provide all the nitty-gritty details and any corrections to my explanation.

Hope that helps
Giancarlo Podio

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