A combination of water column dosing and root feeding is the best approach, though many rooted plants can get away with one or the other.
Water column feeding reaches all plants regardless of the extent or health of their roots (which we cannot see), and feeds plants with greater uniformity. So we recommend water-column dosing as the primary approach.
Root-zone nutrition has unique benefits. It allows us to keep nitrate levels in the water low, which reduces algae risk significantly. It provides an easy way to practice Nitrate Limitation, as it is much harder provide a 'just enough, not above 5ppm, yet not too low’ level of nitrates through water column dosing alone, as plant mass and rate of nitrate absorption can vary alot across different tanks. In 2Hr Tanks, we combine APT liquid fertilisers with APT JAZZ.
Nitrate limitation refers to lowering nitrate levels in the water column and not nitrogen per se. Nitrogen is essential for plant growth and health. Limiting nitrates in the water but providing sufficient amounts through the roots induces stronger coloration in many species.
It depends on whether the root tab is able to effectively retain nitrogen in the substrate. The majority of root tabs provide micro nutrients and trace minerals, but little or no nitrogen. Those that provide nitrogen often do so in a form where nitrates leech quickly into the water (resulting in a spike in N levels in the water), instead retaining nitrogen in the substrate.
APT Jazz contains ammoniacal nitrogen which is preferentially absorbed by plants and contains additional clay to improve CEC content of the substrate. Conventional root tabs are often derived from terrestrial fertilisers, which contain unsuitable ratios of copper and trace elements for closed aquariums. APT JAZZ is specially designed for freshwater planted aquariums, with ultra-low copper and a calibrated ratio of trace minerals.
Osmocote is a brand of terrestrial fertiliser that some aquarists use as a DIY root fertiliser. It can provide good results, but often triggers algae because it is designed for terrestrial use. Some versions contain unsuitable ratios of trace elements, which can make long lasting damage to the aquarium substrate. APT JAZZ was specially designed for the aquatic environment, and calibrated for aquatic plants.
Yes. Conventional root tabs do not pair well with inert substrates because inert substrates do not bind nutrients well. In other words, the contents quickly leech into the water.
APT Jazz contains a slow release mechanism that is highly effective in controlling the release of its contents over time.
If you have a shallow substrate ( less than 1 inch deep), try to place the capsules at the absolute bottom. At minimum, your substrate must be deep enough to hold the capsule securely within the substrate. If it is too shallow to hold a capsule, it is too shallow for APT Jazz, and too shallow for larger plants in general.
In mature tanks with mature plants, remember that deteriorating stems DO NOT rejuvenate as a rule. Adding APT Jazz will not enable decaying stems to rejuvenate.
Especially for stem plants, it is necessary to remove the old stems and roots, and replant the healthy tops. New roots will sprout easily.
Read this post regarding the necessity to regularly ‘cut and replant’.