Greetings from Oklahoma!
I am not a newbie - I began 40+ years ago and have kept/raised SA, kept/raised rift lake, kept/raised reef coral - but one is never too old to learn. I have come full circle, convincing my wife last year to allow one freshwater tank. See my profile for uploaded pictures of past and present tank.
My tank is a 40g Uniquarium rectangular dwarf Cichlid and planted tank. I recently changed out the lighting from a Marineland LED reef to a Marineland LED plant lamp (The reef 10K was burning up the plants and I got tired of replacing plants every three weeks). There is no undergravel filter. Planting medium is Caribsea FloraMax and Caribsea sand (both freshwater).
The water test kit was recently changed from an API Master Test Kit to API 5 in 1 (due to suspension problems with the Master Test Kit's Nitrate titrate solution bottle #2). Here are the strip results:
The fish are gradually dying off. The plants (including Anubias and Sword) are going soft/rotting in the stems and leaves turning yellow and dropping off. Although the water tests are good, I have proactively dosed the tank with Prime. The plants receive Flourish Excel - I have not added Iron - but that doesn't explain the fish die-off. I am doing a partial water change, even though this began after a water change this past weekend.
Any help or advise is appreciated! TIA!