Please Advise Needed

obet_07304

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Aug 9, 2006
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I been in the hobby for about 2 years now. And have started last year to do planted. My tank is heavily planted right now w/ regular gravel. I have been dosing .5ml or 1/8 tsp of KH2PO4, K2SO4 & KNO3 every MWF; 1/8 tsp CSM+B every TThS. 50% water change every Sunday. I have the lights on for about 8 Hours. My PH is 6.2 to 6.3 w/ the CO2 on. My question is am I dosing enough ferts? My plants are growing but most of the Amazon & Nana keeps getting "black spots" on the leaves. I tried rubbing them off but to no avail.:mad: One more thing I just purchased the PMDD Pre Mix from Greg & was wondering how to dose w/ this since the Micro & Macro are already mixed? Thanks.
 

sherry

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Feb 23, 2006
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Maybe I'm reading wrong, but it sounds like you have 5 watts per gallon of light.. that is a lot of light even for high light junkies.

It is hard to know how much co2 you have without a drop checker as Hoppy will tell you. Your ph with Co2 is not a great indicator

and I can't tell from what you have written if you are dosing 1/8 teaspoon of phosphate/nitrate/potassium mixed or 1/8th t of each, but for your tank you need more nitrate at least...

I am certain Tom will weigh in here.. but read his estimated index description and search any of Vaughn's drop checker discussions to help get ferts and co2 up.

Tom recently convinced me to cut from 4 wpg to a bit over 2. I have to say, the tank is still growing like mad.
 

obet_07304

Junior Poster
Aug 9, 2006
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Thanks for the reply Sherry. I do have a drop checker (made by RED SEA). And right now its showing yellow:eek: & my reading from the SMS122 is 6.1. Wont the waste of the fist contribute to the KNO3? Thanks again.
 

Frolicsome_Flora

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Jan 12, 2007
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obet_07304;16614 said:
Thanks for the reply Sherry. I do have a drop checker (made by RED SEA). And right now its showing yellow:eek: & my reading from the SMS122 is 6.1. Wont the waste of the fist contribute to the KNO3? Thanks again.

the nitrification process will produce NO3 as a waste product yes, but in not nearly high enough amounts to provide anything useful to the plants. Get a water report if your using tap water, depending on where you are, they might be adding NO3 directly to the tap water (we get 30ppm added out of the tap).

What water are you using in your drop checker to produce yellow? Read up the threads on standard Kh solutions and either buy, or make a 4dKh solution for it.. that way, when it goes green, youll know that your co2 is something around 25-35ppm.

also, get rid of some of that light, thats a monstrous amount of light.. something between 2-3 wpg should be ample, even for plants that need high amounts.
 

Tom Barr

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Given that adding CO2 increases the growth rates based on the published research between 10 and up to 24X the same growth rate without, what do you think happens to the rate of N uptake for plant growth?

You have 10-24X more growth and usage of C, and plants have about the same C:N ratio.

So it's pretty likely that you also need to scale up the addition of NO3, NH4 is rather toxic and as good inducer of some species of algal spores and NO3 provides a longer easier to dose source of Nitrogen.

Same deal with K+, PO4 etc.
You can add all the CO2 etc in the world, but if you rate limiting step is say, PO4, then you cannot increase growth much by trying to add more CO2.

So, take this same concept and applying it to increases in the world's atmospheric CO2 rise. Do you think that the plants will grow more and suck up the added excess CO2?

Not if they are N, P, K, Fe limited.
So it really depends.

If you are a farmer, and you want to get more out of the added CO2, then adding more Nitrogen fertilizer will be required to maintain the balance between C:N:p:K etc.

In our tanks however, adding NO3, K, etc is easy and cheap.
So we casn easily and cheaply maintain a nice buffer range of nutrient levels so that they never run out.

That way we get the most of the nutrients, and the CO2.

More importantly, now we also get the maxmum growth rates out of the least amount of light.

Less light = less cost, less nutrient demand, less work, less initial cost, less heat, more stable over the long term.

Thus "a light limited tank" is a good way to think of the system.
We have N limited, P limited, trace limited, CO2 limited methods to modulate growth rates, but light is where it all starts and is the main driver of all photosynthetic growth.

Regards,
Tom Barr
 

Tom Barr

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"Phenolic Acids and Nutrient Content for Aquatic Macrophytes from Fall River, California
Spencer, DF; Ksander, GG
Journal of Freshwater Ecology [J. Freshwat. Ecol.]. Vol. 14, no. 2, pp. 197-209. Jun 1999.

We compared seasonal changes in tissue C, tissue N, C:N ratio, and total phenolic acids for five species of submersed plants from Fall River, California. Mean tissue C differed among the five species and was between 35 and 40%, except for Ranunculus aquatilis, which was 26%. Mean tissue N differed among species; Ranunculus aquatilis had the lowest mean value (2.71%) and Zannichellia palustris had the highest (3.74%). Mean C:N ratio was between 9.7 and 12.7."

If you increased the growth rates by adding more CO2, this would change the ratio and limit the plants via N or perhaps P, but typically plants are N limited in most of CA, not P limited like in the Everglades.

Many folks have used the old terrestrial N(1.5%), P, K ratios for aquatic plants, but they have 2-2.5X more N relative to carbon than land plants.

Regards,
Tom Barr
 

obet_07304

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Aug 9, 2006
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Thanks for all replies. Ok, I will shut off 2 of the bulbs. So how much N,P,K I should add? How about the PMDD Pre Mix from Greg, I was wondering how to dose w/ this since the Micro & Macro are already mixed?
 

VaughnH

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The PMDD mixture has no phosphate to speak of in it. So, you need to dose phosphate separately when you use PMDD. I'm not sure what the mix in PMDD is so I don't know what the best dosage is. But, if you use KH2PO4 for phosphate, you can dose about 1/4 tsp or a bit more every other day.
 

obet_07304

Junior Poster
Aug 9, 2006
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Here's the mix per Aquarium Fertilizer:
Contains:
1 part Potassium Nitrate,
1 part Potassium Sulfate,
1 part Magnesium Sulfate, and
1 part Plantex CSM+B.

I tried asking Greg but never heard back from him probably very busy.
 

Frolicsome_Flora

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Jan 12, 2007
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obet_07304;16644 said:
Here's the mix per Aquarium Fertilizer:
Contains:
1 part Potassium Nitrate,
1 part Potassium Sulfate,
1 part Magnesium Sulfate, and
1 part Plantex CSM+B.

I tried asking Greg but never heard back from him probably very busy.

You need to add PO4 as well :)

If you follow the link in my sig to the nutri calculater, it will work out a full EI schedule for you based on your exact tank size, I find it most useful.

Flora :)
 

Tom Barr

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BTW, Greg no longer owns the business, it was sold to Alan who should get back to you.

Greg is in China working and will not be back for sometime.

Regards,
Tom Barr
 

obet_07304

Junior Poster
Aug 9, 2006
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Oh:eek: Thanks for the info, Tom. Maybe that's why I never heard back from him. I used the "contact us" link on AF since 4/28. Tom, if you don't mind maybe you can ask them directly on how to dose the PMDD mix. I know a lot of people have been looking for the dosing routine on this also. Maybe you can make it a "sticky" once you get the dosing. Thanks again.
 

pairustwo

Junior Poster
May 8, 2007
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I'm also curious about this. I made the mistake of thinking that the PMDD pre-mix would come with each nutrient in its own package (which is dumb because it is called pre-mix, DUH)

Any way now I don't know how to dose it. there doesn't seem to be any info anywhere about this pre=mix.

Anyone?