Making your own fertilizer (PMDD)?

[boyohboy]

Just wondering how's everyone experience with making your PMDD dosing. I'm having couple of questions...

1) For the PMDD trace element mix, I've found from the Hagen's site that the chemicals they use for Mn, Zn, Cu are all sulphate salt; boric acid for Bo; sodium molybdate for Mo; Sodium Ferric EDTA for Fe. So the iron is in chelated form. But the ingredient also lists EDTA separately, so I'm thinking how much EDTA should I use in total in the mix?? The "official" PMDD trace mix also contains EDTA but again doesn't say how much. Any thoughts? :confused:

2) Looking at the Seachem Flourish, it contains lota extra stuffs in the guaranteed analysis. How many of these are actually useful? eg. Tin at 0.0000030%?? I'm thinking maybe these are simply impurities from the stock chemicals!? And also, it contains amino-acids Arg, Glu, Lys and Tyr. I'm not quite famility with plant metabolism but I thought plants can make all their own amino-acids so why add them? Are they useful or just for marketing hype?

Welcome for any advice. Thanks

[lmvt]

I would also be very interested in knowing concentrations and dosing for the main trace elements.

[djlen]

Save yourself a bunch of grief.....use either Flourish or less expensive, Plantex Trace + Boron.

Len

[boyohboy]

Or buy the trace-mix powder from a hydroponic (sp?) stores. Having said that, I did make my own trace from chemicals as I can't find hydroponic store locally. I ended up just following the % from thekrib.com but added more iron and enough EDTA so the iron doesn't precipitate out (eg. a bit more than 1 for the molar ratio of EDTA/iron). My plants are growing very well, along with Flourish Excel as "CO2".
I'll probably buy the trace-mix from hydroponic when I go out of town tho, as it's only $3-4 Canadian dollars for 100g which's enough for like 5 litre of trace solution... and maybe add abit more iron to top it up.

[Captain Hook]

Boyohboy check your PMs, I've got a couple of local tips for you.

[beviking]

Grief djlen? You don't use PMDD? Are you just refering to the hassle of mixing and storing? Please share.

And if there is something = to flourish but less $, I'm interested in that too!

Awaiting the ambush from plantbrain, suspected seachem employee... :rolleyes:

[djlen]

No, I don't use PMDD for any of my nutrients. Haven't found any one particular mix because I'm constantly tweaking the dosages.
This works better for me at this point.
But the way I understood the original post was that boyohboy(love the handle) was in the process of mixing a Trace PMDD. I just consider mixing traces together a lot more work than it's worth when you can buy a comprehensive trace mix at a reasonable price.
Did I mis-understand the post?
EDIT: Plantex is just as complete(actually a bit more in some elements) and far cheaper, IME.



Len

[boyohboy]

Originally posted by djlen
But the way I understood the original post was that boyohboy(love the handle) was in the process of mixing a Trace PMDD. I just consider mixing traces together a lot more work than it's worth when you can buy a comprehensive trace mix at a reasonable price.
Did I mis-understand the post?
Len

No, you read my post correctly :) . I agree, buying the pre-mix trace powder from hydroponic store is easiler, and which I'll do the next time around. The only reason I was mixing my own trace was becoz I couldn't find a hydroponic store locally, so I just rolled my own for the moment before I can get it from out of town later. It's just having studying in biochem lab and all, the moment I saw those ingredient list on the Seachem Flourish, I couldn't stop but think (and post) what are all those extra stuffs there for?! :rolleyes: :D

[plantbrain]

You can use 1/2 CMS and 1/2 Flourish also to ease the cost issue and still get some of the tiny traces and Boron.
Ant poison is often Boric acid, and it does not take much to add enough B for the plants.

PMDD is more an all in one thing. Both Traces and Macro nutrients are added together. It's kind of hard to have everything dissolve and it does not add PO4 and enough NO3 etc in many cases.

I add traces separately.
I add KNO3 sperately
I add KH2PO4 seprately

That's all you need besides CO2 etc to add unless your GH and KH are less than 3 degrees(50ppm).

If you don't use CO2 or Excel, don't add PMDD.
If the tank is low light/Excel etc once 2x a week max is more than enough. Moderate/high light, 2-3x aweek or split up into daily amounts if that routine is easier for you.

Dose the chemicals dry except for the Traces.


Regards,
Tom Barr

[lmvt]

If you don't use CO2 or Excel, don't add PMDD

why? For the time being I am still not using CO2. However plants are growing and I have some signs of lack of Fe. Isn't it just a question of dose?

As for Excel - it is supposed to be some photosynthesis intermediate. Does anybody knows which? or if it is malate (which is transported from some cells to other photosyntetic cells as a source of carbon)?

Thanks for the answers

Luis

[Kagh't]

the seachem has tin in it for a reason as it's a micro-nutrient that probably has some function here or there. i doubt it's a left over from stock chemicals if they list it.
as for the amino acids, it's a bit of hype really, though i would imagine the fish may have a slight benefit from them. like you said, plants make their own amino acids, and really have no use for external sources.

[boyohboy]

it is supposed to be some photosynthesis intermediate. Does anybody knows which? or if it is malate
Seachem says it's "polycycloglutaracetal". I dun really know where exactly it goes into the normal carbon-fixation cycle, but could it be some chemical that Seachem invented which will breakdown/change easily into one of the intermediate? :confused: I dont' think the normal plant carbon cycle would have something that is "polycyclo", right??
:confused:

[lmvt]

I dont' think the normal plant carbon cycle would have something that is "polycyclo", right??

I also have no ideia how is that related with the plant carbon cycle. Probably, as you say, is just metabolized to some simple compound used by plants. I tried to find what was polycycloglutaracetal but failed. I am not a biochemist but I think the name of the product is overly simplified so that it is protected. Anyway it would be probably to difficult to get it.

I guess I'll have to try the DIY CO2 one of these days.

[plantbrain]

I said:

--------------------------------------------------------------------------------
If you don't use CO2 or Excel, don't add PMDD
--------------------------------------------------------------------------------

"why?"

That's what fish are for. The rate of NO3, K+, PO4 etc is greatly reduced when the tank does not have CO2 enrichment.
When you add CO2 etc, this increases demand on NO3, PO4, K+, traces etc.

It's relative, Carbon is 40% of the plant's dry weight, N? it's only 1.5% of the dry weight. Wet vs Dry weights run around 9:1.
So there will be an excess of NO3 generally since CO2 is limiting plant growth and hence uptake.

A well set up non CO2 does not need any other additions besides fish food/waste and water for evaporation.
These operate well for many years.

" For the time being I am still not using CO2. However plants are growing and I have some signs of lack of Fe. Isn't it just a question of dose?"

Yes, but the fish waste should be able to supply the needs and you should have some source of iron in the roots zone if you set the tank up right from the start. You can add root tabs for iron but the non CO2 tank is generally never iron limited if you added some iron source to the substrate. Root uptake alone is enough to supply the plants and have decent health and appearance.

PMDD was not designed for a non CO2 tank, nor do they try to argue that point. It weas designed for low light, CO2 eniched tank with PO4 limitation as a limiting element that they hoped would control the algae. That part proved wrong but the approach led the way for a better understanding of dosing.

"As for Excel - it is supposed to be some photosynthesis intermediate. Does anybody knows which? or if it is malate (which is transported from some cells to other photosyntetic cells as a source of carbon)?"

Nope. It's a bound sugar.
It's fine for low light tanks etc, but plants will grow faster, better with CO2, it's more a question of convenience, just add x amount into your tank of X amount of gallon/liters etc per X unit of time.

CO2 is what the plants want but on small tanks, adding excel is simpler in many repsects for some folks.

I use CO2 or non CO2 methods only, but if you use Excel, you remove the carbon limitation in lower light tanks therefore apply the increased N, P, K, GH, Trace needs.

Keep in mind that PMDD was developed using _low light_, non saturating CO2 levels(saturation for plant growth occurs around 30ppm in aquatic plants).

In general there has been a huge increase in lighting/trend over the last 10 years.

Regards,
Tom Barr










Thanks for the answers

Luis