# PMDD mix? now what?



## DarkCobra (Jun 22, 2004)

Poor Man's Dosing Drops (PMDD) is an outdated fertilization scheme that limits phosphate, in an attempt to limit algae without also limiting plant growth. It didn't work very well. The recipe you listed is in the style of PMDD, distinguished by the lack of phosphate and addition of magnesium.

It was also the first major scheme to use inexpensive dry ferts. Thus the "Poor Man's" name. So occasionally someone will still call any use of dry ferts PMDD, even if it doesn't follow a PMDD recipe; which is confusing.

It's unlikely you were actually told to use a PMDD recipe. If you were, it's probably bad advice; any remaining utility of PMDD is limited to experimentation and special situations.

Instead, use the dry ferts to dose Estimative Index (EI) as described here:

http://www.plantedtank.net/forums/fertilizers-water-parameters/21944-_dosing-regimes_.html


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## Jim_PA (Aug 26, 2011)

Thanks for the info. I will check it out. I was going off this post I sent out

http://www.plantedtank.net/forums/plants/152661-dosing-question.html


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## dundadundun (Apr 8, 2010)

DarkCobra said:


> Poor Man's Dosing Drops (PMDD) is an outdated fertilization scheme that limits phosphate, in an attempt to limit algae without also limiting plant growth. It didn't work very well. The recipe you listed is in the style of PMDD, distinguished by the lack of phosphate and addition of magnesium.
> 
> It was also the first major scheme to use inexpensive dry ferts. Thus the "Poor Man's" name. So occasionally someone will still call any use of dry ferts PMDD, even if it doesn't follow a PMDD recipe; which is confusing.
> 
> ...


yes, but considering he already has them... and the others in a separate package, he certainly could dose po4 and N on his off days. the extra mg isn't going to hurt anything. just account for it in your dosing by using 75% of your calculations if you're going by volume. of course you could calculate by molecular weight if you wanted to, but it doesn't have to be that specific.


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## DarkCobra (Jun 22, 2004)

I looked at the link, and it appears they were indeed using PMDD as a generic description for dry ferts, rather than the specific PMDD recipe.

With the nearly comprehensive collection of dry ferts you have, you can dose EI, PMDD, PPS-PRO, MCI; anything you want.

I agree with Dundadundun that a little extra magnesium probably won't hurt, and may help if your tapwater is deficient. I used to dose true PMDD, and when I switched to EI I hybridized the recipes; carrying over some of the extra magnesium and potassium in PMDD to EI. Dosed that way for years. Nowadays most people test GH, and if needed, dose a GH Booster after water changes; which supplies extra magnesium, potassium, and calcium. There's a Pennsylvania ex-native sitting next to me, and she says the water was generally quite hard; so calcium probably isn't necessary.


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## mistergreen (Dec 9, 2006)

PMDD is fine if it's a low/medium tech tank. It's like the seachem fert lines.

There's no point to dosing EI other than a high tech tank with CO2.


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## dundadundun (Apr 8, 2010)

DarkCobra said:


> There's a Pennsylvania ex-native sitting next to me, and she says the water was generally quite hard; so calcium probably isn't necessary.


that's highly dependent on the area and the water plant/supply available. where i sit, they revamped the local plant in 2006 and everything's been so different since it's unbelievable. dgh and dkh <2 at all times. mom's up in the mountains and hers is >15D. other plants up and down stream from me vary widely on the same source water.


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## 150EH (Dec 6, 2004)

I'm have good results with EI dosing, but my tank has just allowed me to start using a full dose, before the addition of a couple of new bulbs in my light fixture the plants were not growing fast enough to warrant a full dose, I think that was an important thing to mention or else you could just be feeding algae.

But with that said I have added 15ml daily of an Fe solution (the same Fe you have 11% DPTA) I added 1 tbsp of Iron Chelate 11% DPTA to 500 ml of water and dose 3 to 6 ml per 50 gallons of tank water, so on my 150 I ended up with 15 ml nightly, but I know folks here that dose double that on a 75 gallon tank, so you need to adjust the levels as needed. My plants colored up with Fe after the first day and I could dose more to bring out the reds in a couple of plants.


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## JasonG75 (Mar 1, 2011)

Here is a great link as well about PMDD

http://www.thekrib.com/Plants/Fertilizer/pmdd-tim.html


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