1) The current recommendations aer:
NO3 - 5 to 10ppm
PO4 - 0.5 to 1ppm
K - 5 to 10ppm
These are not what you should dose but what you need to maintain. So if your tanks already has 10ppm of NO3 after water change, you don't have to add anymore.
2) There isn't any good K test kits, and certainly not easily available at all. It's really no point, you can dose K blind in the 5 to 10ppm range once a week without adverse effect.
For NO3 and PO4 kits, they aren't very reliable. They give you an idea whether you have those in your tank, but the readings can be off. If you wish to, you can use the kits but let the plants tell you the whole story.
PO4 source is from fish food. Your tank is pretty high light. If your bioload isn't very high and if you don't overfeed, chances are your tank should be low on NO3 and PO4. For a start you can try dosing 5ppm NO3 and 1ppm PO4 twice or thrice a week and see if your plants respond. Do this and observe for about 3 weeks, then tweak somemore.
3) No. You should do all 3. Its no point providing only one at a time as the plants will still be limited by the other 2. You should also think about dosing more traces at the same time.
Bookmarks