How to understand osmocote ?

[eminor]

Hello, i made a tank for experiment osmocote, my osmocote is made of :

22% Nitrogen (19.1% urea, 1.7% ammonia)
7% Phosphates (P2O5)
14% Potassium (K2O)

Does those percentage mean that in the package there is 22% of N which is 220 000 ppm, seems a lot ? if it's right there is nearly no way to know exactly how much ferts is in each pellet.

The soil in that tank is clay, don't know the type it's made by tetra, don't know the CEC either, i know that clay is able to exchange Calcium, potassium, is it capable to exchange ammonia too ? thx

 

[erwin123]

Osmocote Plus – Controlled release fertilizer for soilless media | ICL US

Formulated for use in soilless growing media—Osmocote Plus is the go-to fertilizer when growing a wide variety of container plants.

icl-sf.com

You probably bought a 3rd party product as there does not appear to be any osmocote with the composition you describe. In particular, Osmocote doesn't use urea, it uses Ammonium Nitrate and Ammonium Phosphate.

If you could share the webpage of the 3rd party product that would be helpful as there may be more info on the website.

If you bought the product from an unknown China seller on ebay, I would just say be careful as there may not be any way to 'verify' their published figures.

 

[dw1305]

Hi all,

Does those percentage mean that in the package there is 22% of N which is 220 000 ppm, seems a lot ?

That is right, 22% is 220,000 ppm. That is why I'm not keen on <"controlled release fertilisers">, other than at very low dosing rates.

You probably bought a 3rd party product as there does not appear to be any osmocote with the composition you describe. In particular, Osmocote doesn't use urea, it uses Ammonium Nitrate and Ammonium Phosphate.

If you could share the webpage of the 3rd party product that would be helpful as there may be more info on the website.

It would help.

cheers Darrel

 

[MichaelJ]

Does those percentage mean that in the package there is 22% of N which is 220 000 ppm, seems a lot ?

If 22% of the pellets is made of Nitrogen one gram of the pellets would give you 220 ppm of N if fully dissolved in one liter of water. If your tank is say 100 liter that would be 220 ppm / 100 liter = 2.2 ppm of N - quite a lot for only one gram!

I have a bottle of Osmocote Plus (the Original product) and it contains 15% Nitrogen (8.4% Ammoniacal Nitrogen and 6.6% Nitrate Nitrogen). One gram of this will over time release a total of 1.5 ppm of N in 100 liter of water.

I am quite cautious about using Osmocote myself - and I've actually only used it a few times and in very small quantities.

Hope this helps!

Cheers,
Michael

 

[eminor]

Thanks guys, i translated the back package, never saw that it's made in the UK

 

[MichaelJ]

Thanks guys, i translated the back package, never saw that it's made in the UK

It appears that Osmocote, besides being a product/brand owned by Scotts Miracle Gro, is also a coating process for making controlled-release fertilizer. Some other products appears to be using the Osmocote process.

Cheers,
Michael

 

[eminor]

It appears that Osmocote, besides being a product/brand owned by Scotts Miracle Gro, is also a coating process for making controlled-release fertilizer. A lot of products appears to be using the Osmocote process - on license I assume.

Cheers,
Michael

That's why there is Evergreen (new scotts name) label on the back, scotts also own fertiligene, the fertilizer i use, that make sense, does it mean that it's good quality ? It sound better to my ears that there is lower ammonia, urea will become NH4+ in low ph

Does RO water is always acidic/neutral btw ?

 

[MichaelJ]

Does RO water is always acidic/neutral btw ?

Well, this is @dw1305's department ... I am always never really sure about this, but here goes... when the water comes out of the RO(DI) system it will be about neutral 7 pH, but the water is very "reactive" so if you keep it sitting in say a bucket exposed to air without adding any minerals (or increase KH/Alkalinity) it will quickly drop and become acidic - dropping to about 5.5-6 pH or so as it bonds with the air (CO2) forming H2CO3 I believe...

Cheers,
Michael

 

[erwin123]

Yes Scott's is a good brand. Anyway, here's some info on Osmocote. The writeup on Osmocote Exact suggests that different colours represent longevity (i.e. release duration)?

 

[Hanuman]

What's essential to note here is that osmocote is NOT designed to be permanently under water. This means that this slow release high tech marketing speech on those labels is to be taken with a fat grain of salt.
@eminor If I was you I would sprinkle those osmocote very sparingly. Maybe ~1 to 3 max granules for a 2-3 Sq inch area.
As for the substrate (Tetra ActiveSubstrate) you are using, here is some info posted by some other UKAPS member. Tetra doesn't seem to want to release information about this substrate so no one can say if it has a low or high CEC. One way would be to test for yourself by adding some substrate to a glass of water and see if the TDS decreases substantialy, particularly if dGH drops. This would indicate the soil has some level of CEC. To be safe though it would be best if you could find a soil that has a known mid-high CEC. Akadama is one option.

 

[eminor]

View attachment 204309
Yes Scott's is a good brand. Anyway, here's some info on Osmocote. The writeup on Osmocote Exact suggests that different colours represent longevity (i.e. release duration)?

They tell that it need to be used once a year which should mean that the osmocote coat must be thicker and/or they have lots of nutrients

What's essential to note here is that osmocote is NOT designed to be permanently under water. This means that this slow release high tech marketing speech on those labels is to be taken with a fat grain of salt.
@eminor If I was you I would sprinkle those osmocote very sparingly. Maybe ~1 to 3 max granules for a 2-3 Sq inch area.
As for the substrate (Tetra ActiveSubstrate) you are using, here is some info posted by some other UKAPS member. Tetra doesn't seem to want to release information about this substrate so no one can say if it has a low or high CEC. One way would be to test for yourself by adding some substrate to a glass of water and see if the TDS decreases substantialy, particularly if dGH drops. This would indicate the soil has some level of CEC. To be save though it would be best if you could find a soil that has a known mid-high CEC. Akadama is one option.

I once did crazy with other osmocote, never again, i'll go really slow with the amount you said, since i use a clay soil and the clay ball are large, the water should move a bit. It means that some of the omoscote will go to the water column right ?

i'll try to not dose water column, it's risky because as said above, the release rate can't be controlled. I think that few days ago i read a post from @erwin123 that said that he add few pellets monthly to flat the curve of the release, that's clever, i'll try to add one or two pellet every week before water change. I have a map that i'll update everytime i'll put pellet to do not forget how much and where pellets are

 

[Hanuman]

I once did crazy with other osmocote, never again, i'll go really slow with the amount you said, since i use a clay soil and the clay ball are large, the water should move a bit. It means that some of the omoscote will go to the water column right ?

Yes definitely. I am pretty sure the content of the osmocote will leach into the water column. Only way to mitigate this would be to add a thick capping layer above the tetra substrate to slow down the leaching but it will leach anyway.

 

[John q]

One way would be to test for yourself by adding some substrate to a glass of water and see if the TDS decreases substantialy

Now who would be daft enough to do that with tetra active substrate 🤔

Over the space of a few days the tds will rise slightly, suggesting in the early days it will leach nutrients rather than adsorb them.

TDS Rise in new tank

Hi all. Setting up a new tank for some crystal shrimp, I have used lava rock for the scape and tetra soil for the substrate (the tetra stuff is just a hard clay), Pure RO/DI to fill it and daily 100% water changes and I am still seeing a large rise in TDS and GH. TDS went from 0 to 300+ and GH...

www.ukaps.org

 

[erwin123]

There is a large dump of nutrients in the first 2 weeks. Note this was done at 40C to speed up the experiment, so at room temperature, one can expect the release to be a bit longer, maybe 3-4 weeks.

The cumulative graph spread out over 22 weeks is maybe less alarming - note that about max 80% is released. After osmotic pressure equalises, 20% remains in the pellet (aka 'prill ') is wasted' unless the wall degrades/breaks open.

since you know the release curve, you can add a tiny amount of osmocote every 2-3 weeks (instead of all at once) to 'smooth out' the release curve.

 

[eminor]

View attachment 204319
There is a large dump of nutrients in the first 2 weeks. Note this was done at 40C to speed up the experiment, so at room temperature, one can expect the release to be a bit longer, maybe 3-4 weeks.

View attachment 204320

The cumulative graph spread out over 22 weeks is maybe less alarming - note that about max 80% is released. After osmotic pressure equalises, 20% remains in the pellet (aka 'prill ') is wasted' unless the wall degrades/breaks open.

since you know the release curve, you can add a tiny amount of osmocote every 2-3 weeks (instead of all at once) to 'smooth out' the release curve.

Polyon and nutricote seems better, can't find any though. So great to have those informations, my temp water is 26°c, i'll try to add 2 pellets per week in my 30 gallons tank

 

[Hanuman]

Now who would be daft enough to do that with tetra active substrate 🤔

Over the space of a few days the tds will rise slightly, suggesting in the early days it will leach nutrients rather than adsorb them.

TDS Rise in new tank

Hi all. Setting up a new tank for some crystal shrimp, I have used lava rock for the scape and tetra soil for the substrate (the tetra stuff is just a hard clay), Pure RO/DI to fill it and daily 100% water changes and I am still seeing a large rise in TDS and GH. TDS went from 0 to 300+ and GH...

www.ukaps.org

Men like you or me. 😂
If that's the case then clearly it has poor CEC. Do that with akadama and the story will be a different one. I think James who did the experiment with akadama experienced these TDS swings and KH drops in the first few weeks as akadama was sucking up all it could.

Akadama - A cheap substrate

Introduction Having decided that it was time I changed my silica sand substrate for something better I looked around at the options available. For my 200 litre tank I was going to need a fair amount of substrate and all the commercially available ones would cost me a fortune for the amount...

www.ukaps.org