# How much TPN to use with EI



## Tom (29 Jul 2011)

How much TPN should one use as a trace alongside EI Macros? I'm currently using 2ml/25l but I'm worried it might not be enough

Tom


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## clonitza (29 Jul 2011)

I've dropped the TNP+ dosing from 1.5ml/day to 1ml/day in the 70l tank + Dennerle A1 Daily (trace) 0.2ml/day. 
I usually added 1.5ml daily + 5ml after the water change but it was too much (nitrates were > 60ppm)

Mike


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## ceg4048 (29 Jul 2011)

Hi Tom,
            Only the plants can answer that question accurately. Since it's just traces you can go with the bottle recommendation, especially if using tap water. If you're using RO then you might want to add a little more, say double. 

When analyzing the effectiveness of trace dosing, just use Fe as the proxy indicator. If there are no Fe deficiencies such as yellowing of new leaves then your trace dosing is sufficient. TPN also has Mg in it as well so you wouldn't need to add as much Epsom Salt. This is the complete opposite story as compared to NPK dosing of course...  

Cheers,


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## Tom (29 Jul 2011)

Thanks Mike and Clive. I'm using around 4 times the recommended weekly dose (but split to alternate days), so I think I'll ease off a bit. Maybe halve it and look for any problems. I didn't add any Epsom Salts to my EI mix this time, as my water is very hard anyway. All the new leaves look fine too, it's just the original Crypt ones that are going holey/yellow/melting.

Cheers,
Tom


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## ceg4048 (29 Jul 2011)

Yeah, I'd just cut those off and call it good. They'll never get better, just will sit there and rot. Only the new submerged leaves matter. The darker colors of crypts prevents them from being a really good indicator. Green stems will tell you right away. 

Just as a cautionary note, having hard water is not always an accurate indicator of Mg content. That could be all Calcium (or all Mg for that matter).

Trace mix in general, and TPN in particular, is very expensive, so it's definitely worth minimizing it's consumption. That's why I prefer the El Cheapo mixes...leaves more budget for that French Chardonnay I've had my eye on at Tescos... 

Cheers,


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## dw1305 (29 Jul 2011)

Hi all,


> I didn't add any Epsom Salts to my EI mix this time, as my water is very hard anyway.


 As Clive says it is quite likely that all the dGH in your water is calcium, it is only really the serpentine derived soils in S. Cornwall and the Nottinghamshire/Yorkshire/Durham "Sugar limestones" (Permian dolomites) that contain much magnesium at all in the (relative) S of the UK. If your water comes from a chalk aquifer it will have very low Mg levels.

cheers Darrel


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## Tom (29 Jul 2011)

Clonitza said in my journal about trimming the old leaves once the new ones start growing. Just how much hacking would you advise? Just leave the new couple of leaves and massive root system, or would the lack of plants increase my algae chances if it appears? (am still awaiting the diatoms). Should I leave the old leaves until they start to look rough?

I'll keep an eye on the Mg then!


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## ceg4048 (30 Jul 2011)

The old terrestrial leaves should be removed.

Cheers,


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## keymaker (30 Jul 2011)

Actually, I made a calculation with the known ingredients of TPN a couple of years ago and compared them to the EI trace levels recommended by Tom Barr. This is the result:

*To reach EI levels in a planted tank with weekly 50% water changes you need to dose 50 ml / 50 l / day.*

As Tropica recommends a minimum of 25% water change every second week and dosing 5 ml of TPN / 50 liters / week it is clear that in order to reach EI levels one needs to overdose a minimum of five-seven times the factory values... But as Clive rightly said your plants have the final word, the rest is science.


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## yme (22 Aug 2011)

hi!

my first post at this forum (without introduction: how rude!)
(normally I just post at barrreport.com)

anyway: I read sometimes this forum and I noticed this thread and especially the post by keymaker.



> To reach EI levels in a planted tank with weekly 50% water changes you need to dose 50 ml / 50 l / day.



50 ml/50 l/day seems a factor 10 too high, considering the sentence following this one... but even 5 ml/50 l/day doesnt seem to fit the EI recommendations:


20-40 gallon=75-150 liter (let's average that to 100 liters)

recommendation: 3x 5ml/week =15 ml/week= 2.14 ml/day.
=2.14 ml/day/100 liter
=1.07 ml/day/50 liter

1 ml/day versus 5 ml/day. 

seems like a factor 5 difference....

So I was wondering 2 things:
-what are the desired trace concentrations recommended by Rom Barr?  (never read that Tom Barr wrote somewhere the recommended levels)
-How did you calculate everything?

greets,

yme


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