I set up a new 30 gal long tank to re-home my gold barbs from their current 20 gal tall tank. Low-tech with LED plant grow light, java fern, java moss, anubias, amazon sword & a couple of plastic plants (grass on the left end of the tank). Not heavily planted - covers about 1/3 of the floor surface area). Mystica II sand substrate. Also added API root tabs, Easy-life ProFito and Flourish Excel. The old tank has an established and over-sized filter that I can simply transfer to the new one along with the fish, but I wanted to give the plants a couple of weeks to establish themselves before I add the fish. My gold barbs would leave the java fern and anubias alone, but they'll make salad out of the swords within days unless they are lush and strong (based on past experience in the old tank).
It has been 6 days now and the amazon swords are starting to die. Leaves are dull and transparent. Macro nutrients are probably insufficient since there is no fish waste yet. But have been adding fish flakes everyday assuming that it will decompose to produce NPK, but I guess it is not enough and hasn't had enough time to decompose sufficiently yet (?).
Water parameters were tested everyday for the past 6 days and still show zero nitrate and less than 0.5 ppm ammonia, so nitrogen source is insufficient for the plants. These are based on test strips though, I am yet to get the more reliable API master kit.
Is there a good source of NPK I can add to help the plants? The hardy ferns and anubias are holding up, but the swords are on their last leg. I came across a liquid fertilizer made of fish parts (ironic) with 2:2:2 ratio of NPK. Brand name -"Alaska All Purpose Fish Fertilizer. Is this usable for the aquarium? I was also thinking of adding surfactant-free ammonia if needed (to get the right ratio of NPK (?)). I also have a spare bio-wheel floating in the old tank that I can transfer to the new tank if needed. Right now I just have a mechanical filter in the new tank for water agitation. No carbon filter.
Any advice on how to proceed would be appreciated.