Algae + nutrient deficiency help!
I'm trying to trouble shoot a nutrient deficiency right now. Symptoms effecting old leaves so I'm figuring it's either N, P or K. My aquarium is heavily stocked. And I've heard that a heavily stocked aquarium might not need to dose NO3 or PO4. I know that all depends on how many plants I have though. I just want to know if I can trust my phosphate test. Someone told me nitrates can hide out in the substrate and a standard water column test wont show them obviously. If this is true for phosphate it adds another layer of difficulty trouble shooting.
Right now I have Flourish Potassium, Flourish Comprehensive, Flourish Iron, and Flourish, Nitrogen. My nitrate test shows it's barely above 0 or basically I know it's not 0 but it's definitely not much higher.
I just started to get GDA slowly growing on my walls. I cleaned the walls did a water change and took light duration down by half. Algae did not increase in 4 days. With the plants being nutrient deficient I'd rather bring the light and co2 back up. But unless I can get this nutrient deficiency problem figured out all that light and co2 might as well go towards more algae.