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Using non-standard ingredients for DIY fert solutions ie Urea, MnSO4, Citric acid, hydrochloric acid

ShawnMac

Member
Joined
4 Aug 2015
Messages
123
Location
ND, USA
So, I've been evaluating my fertilizing approach. EI has worked successfully and I have no complaints, in fact I look to probably scale back the dosing a bit from previous solutions. In reading a few things here and there I've begun to think about additional additives in the process and have a few questions I have been unable to find adequate answers to and hope the folks here could be of some help.

1)Using acid as a preservative. In the past I have used excel and it works fairly well. Usually a couple months without growth. I've read that an acid can enhance the effectiveness of chelators. I think I see some precipitate in my micro solution after a period of time and wonder if an acid preservative would help with this. a) can I still use excel with HCL or Citric acid? b) Any guidance on how much to add to a volume of micro solution? My autodoser has a 1500 ml reservoir.

2)Any truth to the idea that creating an acidic enough solution allows someone to create an all in one solution without PO4 and Fe precipitating out? I cannot recall nor find again the resources from where I first read this.

3) I've noticed some commercials fertilizers use two sources of nitrogen, likely KNO3 we all use, and Urea. Any guidance to using Urea as a secondary source of Nitrogen? Are plants better able to utilize urea or is this just more marketing claims? If it couldn't hurt and I feel like trying any guidance on how much to add to my solution of macros? This is what I found on Amazon and am EXTREMELY rusty on my stoichiometry so wouldn't trust myself calculating it. Any help would be appreciated.

4)Any benefit to using MnSO4 to beef up the Mn content of Plantex CSM+B? In reading some of the DIY Tropica Mastermix threads and info I came across Wet's analysis of the ratio of iron to manganese in Tropica compared to Plantex on The Barr Report and noticed the discrepancy.

I'm planning to shoot for lower end of EI range for dosing this round in terms of nitrogen. I would like to see some color induced by nitrate limitation without some of the drawbacks of too lean of dosing elsewhere (so why the Urea question anyways then...yeah...I know). I'm thinking rich Fe (and maybe additional Mn), rich K, heavier P...and light on the N ( 10 ppm?). I will use the calculator at Rotalabutterfly.com to calculate for my targets. Any comments on this idea at all?


*UPDATE*

Used Jame's Planted tank to narrow down the acid I plan to use Ascorbic acid and the preservative Potassium Sorbate. Not sure if I'll make an all in one solution however.
 
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Interesting topic.. :)

What little i know from Urea it is not readily available for the plant it first needs to be nitrified by the bacteria this process takes time, While NO3 is readily available from the waterbody. In this nitrification process ureum forms an Amide, another form of N, which triggers a darker color and compact bushy growth, so it's not a marketing claim.. It is indeed regularly used in terrestrial fert solutions, where it definitively has benefits, but also downsides as it can wash away before its nitrified and or gasses off before used by the plant. It is also used as spray fert on the leaves, but with caution because it can cause significant burn on the leaves.

Using it in aquarium with more extreme caution and experience.. My best guess is, putting it in a fert tab into the substrate would be the safest way of adding it in very low concentration.. I never did.. I bet Darrel can tell you a lot more about it.. :)
 
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Couple of points...

- There is no place for strong acids in fish keeping (ok maybe limescale removal).
- Urea is toxic to live stock even in quite small doses.
- Commercial fertilisers, even ones for fish tanks, use urea as it is cheap and provides a lot on N for your money (and their profit) but is only supplied in weak doses so as to not kill your fish.
- Most people who invent and roll their own EI dosing end up with plant issues.
 
Couple of points...

- There is no place for strong acids in fish keeping (ok maybe limescale removal).
- Urea is toxic to live stock even in quite small doses.
- Commercial fertilisers, even ones for fish tanks, use urea as it is cheap and provides a lot on N for your money (and their profit) but is only supplied in weak doses so as to not kill your fish.
- Most people who invent and roll their own EI dosing end up with plant issues.


A couple responses:

These strong acids are added to fertilizer solutions, removing KH and preserving the chelator for a longer period of time. For me this is helpful when creating a solutions for my auto doser reservoir. Strong acid depends upon the molarity of the solution, not necessarily the components ie HCL, H2SO4, Acetic acid, citric acid, absorbic acid (Vitamin C).

Urea converts to ammonia which has the potential for toxic effect. I've learned it has been dosed in aquariums, measured, and can be utilized to provide nitrogen. I've seen up to 0.8 ppm doses are safe. I know of several accomplished aquascapers using it to supply N.

Cost may indeed be the reason for utilizing urea or ammonia, however there are also biochemical and metabolic advantages for plants. KNO3 is much safer to use with a very wide safe range.

I am not inventing my own and am not a newby nor chemistry illiterate. I certainly wouldn't suggest using Urea for someone new. While I think standard EI is great and has little disadvantages I am also evaluating other approaches which do not actually stray from EI, since EI is simply the concept of supplying nutrients in non limiting quantities and less to do with the additives utilized to supply those nutrients. My straying from EI is actually in considering induced intentional nitrate limitation to produce colors in some plants. Believe it or not, EI is not used round the world and lean dosing is a very common strategy utilized by many in the far east.
 
Hi Shawn, :)Another learning curve in chemistry for me. Reading ;)

I wish I could recall all of my chemistry. I took a great deal at University, but have not used it since the courses and so lost a good deal of information that would be useful for me in the hobby. The courses were miserable and difficult so I'm not too keen on revisiting my textbooks. :meh:
 
so a little update on what I did...

I used acetic acid since I had it on hand at 10 mls per 500 mls. Went back to using distilled water, this is really much better than tap as there is less chance of some strange precipitate forming and the pH can be dropped easier. Solutions mixed much easier with the acid and the distilled.

Has anyone been using the calculator at Rotalabutterfly.com ? I have used it a few times and I am not certain it is accurate. My main concern is that molecular weights were not used and that the concentrations could be off. My micro solution with the added iron to 3 ppms is tinting the water. EI range is 0.5 ppm to 5 or 6 ppm. The 3 ppm was an error on my part I was shooting for 2 ppm using the nutrient accumulator tool on the site. While this isn't really "roll your own" since I am in targeted EI ranges, just not using the standard amounts found everywhere since I wanted to control for targets better. Has anyone dosed 2 ppm or more Fe before? I have heard of folks doing it often, but never heard of water tinting, which makes me think the calculator is either off or I am using it incorrectly.

I will be using Urea at 0.4 ppm and 2 ppm KNO3. Phosphate will shoot for a 2 ppm level and the K will basically be as much as I can get in with K2SO4 and whatever is added by KNO3 and KH2PO4.

I really need to confirm if the nutrient calculator works right. Wet's calculator was great and you could say this is his legacy after he passed taken up by several great hobbyists...but if these guys are programmers and computer guys I wonder how sharp they are on the chemistry side and if there could be errors from that or even just importing Wet's code to a new code. I am not anywhere near being a programmer so really have no clue what I'm talking about in that regard. Anyone have any idea on the online calculator?

I found some great info on PPS-pro using Urea and may just use that to create a lean dosing regime instead of EI with lean Nitrate. EI is fantastic and really great for beginners, but as I've advanced I don't want to be flushing so much down the drain every week and with aquasoil leaner dosing can be done with good effect. I feel this is something experienced hobbyists should start to consider eventually. I've dropped EI to 1/3rd in high energy systems using aquasoil to no ill effects. My strategy moving forward is going to be heavy soil maintenance with regular root tabs and lean water column dosing...then adjust based upon observations. I think PPS-pro may be the way forward for me.

My notes from dosing formulation:

25 ml dose volume broken into 5 ml, 5 times a day

Fe target: 2 ppm with dose adjustment from 25 ml to 17.5 ml

1 ppm from Fe DTPA at 99 g to 1500 ml

0.5 ppm from Plantex 83.4 g to 1500 ml

N target: 4 ppm

KNO3 at 35.5 g to 1500 ml (2 ppm from KNO3)

Urea as secondary source increasing available N, daily addition of 0.4 ppm (half of suggested max and equivalent to 2 ppm N from KNO3 according to Tom); 9.3 grams Urea

K added: 1.26 ppm

P target: 2 ppm

KH2PO4 at 16.6 g to 1500 ml

K added: 0.82 ppm

K target: basically as much as I can get in using K2SO4; roughly daily 3.2 ppm plus other sources for a total of 5.4 ppm reaching a peak accumulation within EI range of 10.4 ppm.

77.7 g K2SO4

The tinting of the water makes me nervous. I have some hesitancy trusting the new calculator created from Wet's. I do not know how it has been validated.
 
A quick verification/comparison using Aquarium Calculators and Rotalabutterfly.com of my ppm from Plantex dose verifies the 0.5 ppm added from the dosing. I will assume the rest is accurate. Now to reconsider my target.

Am I mistaken to think 2 ppm is a reasonable EI range for Fe? Aquarium calculator does not allow for the input of Fe DTPA (11%) which was used to beef up the iron content in the micro mix. I have seen this dose used many other places and no mentions of tinted water. It is definitely the iron doing it.
 
Hi Shawn
I think u meen 2 ppm for the week , u can see the Rotala change the dose for Ei to 0.2 ppm before it was 0.5.
U can try and see... if there is any problem with 2pp.
I use dtpa fe, it make litle yellow the water, no too much.
Try this one it have dtpa fe 11 %
Zorfox calculator u can download it from here.
http://www.zorfox.com/plantedtank/
 
Thanks. Yes the accumulated amount would be 2 ppm

sent from tapatalk on my phone so auto correct and other errors are bound to happen
 
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