I use some clay cones to put in the substrate for the big crypts and the Nymphaea.. (110 litre tank + 15 litre sump) Averagely once every 7 to 10 days a water change about 40%, could be a tad much for a low tech but my reference is water color. Got a lot of wood that still leaches, looking through the side panels i see a white wall and the frontpanel from the inside, the color of this wall through the tank and the biofilm or algae on the front panel is my cleaning sessions and water chance reference.
After water change once a week i add potassiumsulphate >20ppm and potassiumfosfate <2ppm fosfate makes >20ppm potassium and magnesium, day after 3ml Micro solution 3 days later 3ml micro's again. Also add 25ml Rhizotonic weekly, with this i experience mosses growing like a rocket compaired to the tank i do not dose it. Especialy Fissidens fontanus, which is flagged as an advanced moss to grow, grows like a charm in my low tech.
Regarding testkit i know i have Nitrate from the tap. Regarding the water companies report > 40ppm. So i do not dose any Nitrates, i look at my floaters as fert indicators till now they tell me i do not need t add nitrates.
This tank gets a lot of daylight from a roof window above it, in the summer months i'm forced to dose liquid carbon. Against my wishes, but till now i have no other means to prevent spot algae on all the anubias.