# [Wet Thumb Forum]-PMDD Recipe



## The Bishop (Mar 11, 2004)

Maybe I missed this post or can't find it in the archives...but does anyone know of a good recipe for PMDD, including possible sources for the ingredients? An article on usage and mixing would be helpful, too.


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## The Bishop (Mar 11, 2004)

Maybe I missed this post or can't find it in the archives...but does anyone know of a good recipe for PMDD, including possible sources for the ingredients? An article on usage and mixing would be helpful, too.


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## nino (Oct 2, 2004)

Is this what you're looking for?
http://www.thekrib.com/Plants/Fertilizer/pmdd-tim.html

I get the ingredients from www.gregwatson.com

Greg e-mailed me and told me that the new ingredient only use 1tsp of Potassium Sufate and some people don't even use that ingredient if they use KNO3. You've gotta play around to get the right combination yourself and use the recipe as the starting guide.


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## The Bishop (Mar 11, 2004)

Hey, thanks! Exactly what I was looking for. I actually came across that page a while ago and never bookmarked it.

Anyway, I've been reading some older threads, and here are a few things I'm concerned about:

Trace and Nitrogen are obviously taken care of by this PMDD stuff. What about P? I know you can't mix in fleet enema because it will remove both itself and any iron in the mix eventually.

Also, I read somewhere that standard PMDD doesn't contain enough K for most setups. Is there a way to get more into the mix without really increasing the levels of anything else, or would it be just fine to add more KNO3?

I have also seen quite a few posts talking about Ca levels in the tank. The tap water in Detroit here is GH 10-13 right out of the tap. Is it probable (without going to the pain of buying a kit and testing it) that there is already enough Ca in my water? What might be the signs of Ca deficiency in my plants?

And one other thing. People on this list talk about actually dosing the compounds individually. How is this accomplished? Do you simply add the powder to the water, or do you dissolve it first in a quantity of water and eyedropper it into the tank? If so, what are good mixing ratios?

Thank you in advance to anyone patient enough to answer my questions!


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## The Bishop (Mar 11, 2004)

Well, I just went to the local hydroponics shop and asked for chelated trace element mix and Potassium Nitrate. After asking me to explain why I wanted these things and interrupting me while I told him, the guy there told me that KNO3 renders any animal it touches impotent and is a carcinogen. He said he knows planted tanks, and since he has a "prize-winning" one himself, I should just use Flourish like he does. I thanked him for his help and left.

Looks like I'll be hitting the internet for this one.


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## hubbahubbahehe (Mar 29, 2004)

i believe his rudenessosity is due to 9/11.


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## nino (Oct 2, 2004)

Bishop,
This is the summary I got from reading all Sears-Conlin papers and the comments/critics.

The main reason of their experiments is to control algae while using fertilizer. And their assumption is that Phosphate is the #1 culprit of algae problem. That's why there is no P there and also that the Phosphate from fish food and decaying leaves are enough for planted tank. Their PMDD mixture is actually rich of K. They use KNO3 and 2 tsp of Potassium Sulfate. Many people complain about the large amount of potassium in their mixture and they came out with the formula using 1tsp of Potassium Sulfate.

Some people also only use either Potassium Nitrate or Potassium Sulfate. If they think that their Nitrate is high enough because of the fish and other reasons, they only use P.sulfate in the mixture. If they don't have enough Nitrate, they use KNO3 but no Potassium Sulfate.

This is highly debatable topics. Some say too much potassium is bad other say not. Some says you need appropriate Phosphate level and other don't like it at all.

So I just use the newest formula as a starting guide and go from there. Anyway I only mix in a small amount every time so there are plenty of leftover.


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## nino (Oct 2, 2004)

Oh, regarding the Ca contents in your tap or maybe Magnesium, you can go to Googles or Hotbot, type your city name+water. Ex. Las Vegas water and then search. There should be a site from your local water company. Look for the water analysis. All the details are there.

Regarding the calcium deficiency, go to:
http://www.csd.net/~cgadd/aqua/art_plant_nutrient.htm


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## The Bishop (Mar 11, 2004)

Has anyone tried (NH4)2SO4 + FeSO4 + 6H2O (ferrous ammonium sulfate) with something like K2Mg(SO4)2 or MgSO4 in combination with K2SO4, or maybe even KH2PO4? There is NH4 in the ferrous ammonium sulfate, which Walstad's book says plants prefer as their N source over NO3 anyway.

Just toying with ideas for now. I'll probably end up with the standard formula for starters anyway. Just wondering if anyone had tried something like this.


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## DanD5303 (Oct 12, 2004)

The article that's referenced above is dated 1997. In just the two or three years I've been following this stuff several things have changed. I'm not sure if anyone still tries to stop algae by limiting phosphate, but I know from experience that phosphate levels as high as 4 mg/L don't cause algae if the nitrates are right. I think that if you google Tom Barr's Extimative Index you might find useful information. There are a lot of interesting ideas about fertilization-the more you read, the more you will know??? I do think you should test your water and then use dry chems to bring it up to whatever levels you decide on. Dan


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## DJ (Nov 26, 2003)

> quote:
> 
> Has anyone tried (NH4)2SO4 + FeSO4 + 6H2O (ferrous ammonium sulfate) with something like K2Mg(SO4)2 or MgSO4 in combination with K2SO4, or maybe even KH2PO4? There is NH4 in the ferrous ammonium sulfate, which Walstad's book says plants prefer as their N source over NO3 anyway.


Well, I've been dosing macro elements using
ammonium nitrate (NH4NO3) is nitrogen source and a MgSO4 / K2SO4 mixture for potassium. It works, but it is tricky:
1. Mg makes your hardness go up.
2. ammonium nitrate contains ammonium. This can onlybe used under (slightly) acidic water conditions otherwise you'll kill all fish within seconds. To make sure the ammonium is gone fast only use it when the lights are just on this because a. plants grow fastest then and take it up fast and b. There will be abundant oxygen around for a long time for the little friends converting it to NO3 if it is not gone.
3. 9/11 ammonium nitrate can be much worse than KNO3.

Since I traced a source of KNO3, KH2PO4 and K2SO4 I only use this for nitrogen, phosphate and potassium.


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