diy root tabs

[Christos Ioannou]

I am running an 180L tank with 3 23W CFL bulbs, FE CO2 and a powerhead next to the filter output to enhance circulation. I am also dosing EI.

I am targeting towards a carpet of Eleocharis Parvula.
Four weeks in, I can see runners here and there. I am inclined to use DIY root tabs. I can see references to osmocote, micarclegro slow release fertilizers. Unfortunately, none is available where I live so I either have to buy online or settle with what I can find in local stores.

Which ingredients should not exist in the composition of a slow release fertilizer to make it safe for the aquarium?

 

[ian_m]

Fertiliser for use in aquarium, with fish present, should not contain ammonia/ammonium or urea based compounds as both are toxic to fish. eg usual cheap land based fertiliser is ammonium nitrate.

 

[Jose]

Root tabs must have NPK in them. You can combine iron/micronutrient ones with NPK/macro ones.

Which ingredients should not exist in the composition of a slow release fertilizer to make it safe for the aquarium?

None really because its slow release, and not much if at all is going to leach into the water. This is for the case of root tabs of course and not water column ferts. Every root tab that has NPK is going to have ammonia for sure.

 

[ian_m]

Every root tab that has NPK is going to have ammonia for sure

Not so. The specialist aquarium ones, specifically state no ammonia and the version of Osmocote (Osmocote for people are using is virtually ammonia free. I would rather hope they are ammonia free (or very low), as you don't want an "escaped root tab", as dug up by a fish, dissolving quickly in the water leaching ammonia.

Of course people are using Osmocote with ammonia by placing it right at the bottom of their substrate (mixed in peat or soil), where it can leach ammonia slowly, but could always be a risk that if you disturb the substrate too much you could release ammonia.

Here is Outdoor Osmocote ingredients, nitrogen provided by ammonium nitrate & ammonium phosphate.
http://www.plantersplace.com/products/osmocote_outdoor_indoor

 

[Jose]

This is from the link ian:

GUARANTEED ANALYSISF643
Total Nitrogen(N)†15%
8.4% Ammoniacal Nitrogen

It would be great if you have a link to the ammonialess ones. It would be really new to me.

There are two sources for nitrogen: Main and cheapest one is ammonia salts/urea etc and the other one is KNO3. This not not commonly used I suppos because of its price. I do agree that there are low ammonia ones but its still ammonia.

 

[Jose]

Of course people are using Osmocote with ammonia by placing it right at the bottom of their substrate (mixed in peat or soil), where it can leach ammonia slowly, but could always be a risk that if you disturb the substrate too much you could release ammonia.

This is the same risk as using a fertile substrate, or isnt it?

 

[ian_m]

This is the same risk as using a fertile substrate, or isnt it?

No a fertile substrate, for aquatic use, will (hopefully) be using ammonia free fertilisers absorbed in it, generally potassium nitrate and potassium phosphate and/or variations of. Though when starting a tank up, some substrates generate a bigger ammonia spikes than others, though I suspect no due to ammonium based salts in the substrate.

t would be great if you have a link to the ammonialess ones

I think the Pro+ version had less ammonia, but is difficult to find.

You can use normal Osmocote in small quantities, by freezing some Osmocote (10 grains ?) in ice cubes and pushing under the substrate, some people say at least 4cm under, so no chance of it escaping. Or if substrate not deep enough, roll some grains in potters clay, let dry and push into substrate. The JBL balls as just balls of clay with fertiliser in (no ammonia based though).

 

[Jose]

No a fertile substrate, for aquatic use, will (hopefully) be using ammonia free fertilisers absorbed in it, generally potassium nitrate and potassium phosphate and/or variations of. Though when starting a tank up, some substrates generate a bigger ammonia spikes than others, though I suspect no due to ammonium based salts in the substrate.

Im afraid that all these substrates that provide nitrogen provide it in the ammonia form because it comes from some kind of organic substance. They are not made with potassium nitrate because this just dissolves and and is much more expensive to use in a soil. With time the substrate matures and the ammonia is oxidized by the bacteria in the soil to NO3.

The root tabs or soils that say "no ammonia" is because they lack the nitrogen part of an NPK fert. So you are not supplementing your plants with a basic macronutrient to its roots.

 

[Edvet]

When i feel the need to add ferts to the soil i make a batch of dissolved Ei Salts and inject them under my substrate, just push a needle to the bottom and slowly inject.

 

[roadmaster]

If dosing EI as OP mention's, I would not worry bout root tabs.
Plant's as I understand it, will take up nutrient's just as easily from the water as they will from their root's?

 

[Jose]

If dosing EI as OP mention's, I would not worry bout root tabs.
Plant's as I understand it, will take up nutrient's just as easily from the water as they will from their root's?

True!

 

[Christos Ioannou]

True!

I hear what you say but let me add that I am using Tesco cat litter as substrate, and I want to achieve carpeting with Eleocharis.

This is a high CEC substrate yet not enriched in any way, although by now I would think it has absorbed quite an amount of nutrients. Thus I assumed root tabs would be beneficial to Eleocharis - I used Tropica root tabs when planting ~4 weeks ago and wanted to repeat that maybe in a month; this time with DIY tabs.

If EI with a high CEC substrate is enough for eleocharis then I see no reason for root tabs either.

The small surface area of eleocharis blades drives me into thinking that not as many nutrients can be absorbed from foliage (compared to alteranthea for example) and root feeding -suplementing EI- would be beneficial to this plant.

Your thoughts?

 

[Jose]

The small surface area of eleocharis blades drives me into thinking that not as many nutrients can be absorbed from foliage (compared to alteranthea for example) and root feeding -suplementing EI- would be beneficial to this plant.

This is your intuition but you have to look at the facts. Ive grown an eleocharis mini carpet without a fertile substrate, just black sand. Others have as well. You can also add root tabs since it will also help but its isnt mandatory. You can use any root tab that you can find even for terrestrial plants.

 

[Christos Ioannou]

This is your intuition but you have to look at the facts. Ive grown an eleocharis mini carpet without a fertile substrate, just black sand. Others have as well. You can also add root tabs since it will also help but its isnt mandatory. You can use any root tab that you can find even for terrestrial plants.

Great! This is very useful to me - that you and others managed to grow a carpet with the mentioned setup.
Thank you all for your input.

 

[Jose]

Much more important is CO2 imo this is the achilles tendon of this plant.
In your comparison with althernanthera, this one has bigger leaves to gather the co2 but it has to build bigger leaves as well right? And there are more factors at play than just leaf size, the main one might be genetics (how this plant copes with low co2 and the environment where it evolved).

 

[Christos Ioannou]

Yes, I understand that CO2 comes first as far as nutrients are concerned.
All these factors we need consider to mimic nature in a contained environment makes me appreciate nature so much more, let alone people who actually achieve it!

 

[Christos Ioannou]

Came across this garden fert. 15-6-12. Comes in granules. Suggested application 2-3 times/year (slow release?)

15% N
- 6.5 NO3
- 8.5 NH4

6% P2O5
- 4.8% soluble potash

12% K2O
2% MgO
9% sulphur
0.02% B
0.01%Zn
Low chlorine

Is it good for root tabs? How can i check? Thanks.

 

[ian_m]

Nope has NH4 toxic to fish. Probably ammonium nitrate.

 

[Christos Ioannou]

So I should be looking for NH3 i/o NH4 ? Thanks.

 

[ceg4048]

Nope has NH4 toxic to fish. Probably ammonium nitrate.

So I should be looking for NH3 i/o NH4 ? Thanks.

There is a lot of confusion over this. Please read the following carefully:

NH4 has LOW toxicity and NH3 has extremely HIGH toxicity. Unfortunately, whichever one is placed in the water, BOTH appear as they exist in equilibrium.

How much of each depends on the pH of the water. At lower pH, NH4 dominates and at higher pH NH3 dominates.

However, the story is even more complicated. At lower pH, even though there is less NH3, that compound is more toxic at low pH than it is at high pH, so smaller amounts of NH3 does more damage.

That's why you want to avoid NH3/NH4 unless you know what you are doing.

If you are asking this question then you do NOT know what you are doing, so avoid this chemical for now.

If you want to add DIY root tabs (which, if you are dosing the water column you don't need to do this anyway) then just use your existing fertilizers dissolved in water and put them in ice cube tray. Freeze the cubes and then take them out of the freezer and push them quickly into the substrate.

Cheers,