Root tabs

[FishNChips]

I have been using Ghazanfar Ghori's macro A, B mix for a while and seems to work nicely with Amazon Swords, Java Fern, Anubias and Sagittaria subulata. I also use SeaChem Flourish for micronutrients.

At the last GWA meeting I learned the value of root fertilization, particularly for the Swords. I am, of course, now wondering what brand/guaranteed analysis needed. I presume I would want to 'match' Ghori's macro as best as possible, but I am not clear how to do that given his calculations.

Any thoughts or experiences with brands or other methods for root fertilization?

Seachem Flourish Tabs
API
Osmocote
or Jobe's plant spikes
GLA Tropica Nutrition Capsules

[krisw]

Paul, there very well may be an optimum root tab to use, but at least in my experience, the root feeders aren't going to be picky. As Cavan mentioned during my talk at the last meeting, the roots are sophisticated enough to only take the nutrients they need, and if you bury the tab deep enough under the substrate, they work leak out in any quantities enough to mess with your dosing ferts. Personally, I switch between Flourish tabs, Miracle Grow spikes, and Osmocote Plus. I can't say I noticed a significant difference either way, so I tend to mix up the Flourish tabs (more micros) and one of the other two when I use them.

[GOT MTS?]

I use Jobes, they're cheap and readily available at Lowe's. The plant roots find their way right to them.

[FishNChips]

Thanks. From what i can tell, the spikes only have the macros (4-4-4 NPK), while the Seachem Tabs have much lower NPK, but a wider diversity of micros (calcium 15%, Mg .06%, boron, .03%, Iron 2.2%, etc.).

There seems to be a lot of mention of using Jobe's on various forums (including this one), so it might be the cheaper starting point.

[halak]

I use Jobe's sticks, as well.

[FishNChips]

From and old Ghazanfar Ghori' post that may be of interest, seem like the NPK ratio is quite different, but I remember from the meeting that the plant takes from the root tabs what it needs.

Research I've done indicates that aquatic plants
need a ratio of 10 : 1 : 10 N : P : K

There is a good summary write-up on the GLA website on fertilizers, but it seems to be, um, borrowed from this Cornell link.
https://nrcca.cals.cornell.edu/nutrient ... 010102.php

[Wobblebonk]

I personally use osmocote plus and just vacuum the balls out if they make it on top of the substrate. Sometimes I push them in individually, sometimes in animal geletin capsules (also a slow release N source). Ammonium! ?

I don't get how it's possible seachem lists calcium chloride but not calcium sulfate when it's 15% Ca 12% S and all their listed sulfates come out to diddly squat. More like derived from a load of crap. I actually use these a little bit with O+ though sometimes.

Jobes is made of bone meal, feather meal, and potassium sulfate, nfc how much calcium but there must be some. Sounds like ground up chickens and potash but hey... it's organic right?
"However, recent CSU research has shown that P from bone meal is only available to plants in soils that have a pH below 7.0." not entirely sure what that means in your aquarium... https://web.archive.org/web/20110721180 ... s/234.pdf#

I know nothing of API or GLA tabs.

[JLW]

OK, ready to get your nerd on?

Bone meal is exactly what it sounds like, ground up bones. It has some nitrogen in it, but not a lot, and is mostly a source of calcium and phosphate. Indeed, bone meal can be approximated as Ca3(PO4)2 and also Ca10(PO4)6(OH)2. By weight, calcium makes up a bit less than 60% and phosphorous about 30%, with the rest being nitrogen, magnesium, salt, and other assorted gunk. When the calcium salts are in an alkaline state, they're relatively stable, and can only be broken down by mycorrhizal action; certain fungi are able to get at that phosphorous, but otherwise, it might as well be part of rock, because... well, its part of a rock. When you lower the pH, though, you have a ratio of H / OH that favours H+, that is, more free H+ ions.

Once you expose those calcium salts to an acid, they tend to break down pretty quickly -- for example, if you have, say, nitric acid:
Ca3(PO4)2 + 6HNO3 + 12H2O --> 2H3PO4 + 3Ca(NO3)2 + 12H2O, and that H3PO4 is quite accessible to plants in water. (A similar reaction would occur with any acid -- which exists if pH < 7.0). Similarly, the Ca10etc gets broken down, allowing that PO4 to be gobbled up by plants.

Now, in a planted tank, do we really worry about pH affecting this? Chances are, we're pumping in CO2, and that'll produce carbonic acid OC(OH)2, which will nicely substitute for the HNO3. Even there, especially in the substrate, microbial activity tends to lower pH.