Understand pH, GH, KH, TDS, ammonia, and nitrate in practical keeper language.
General hardness reflects calcium and magnesium. Carbonate hardness reflects buffering capacity. TDS is a conductivity-driven total dissolved solids estimate that includes far more than useful shrimp minerals. Treat each number as different information.
Nitrification consumes carbonate. In low-KH systems, pH can fall far enough to slow or stall the cycle. Soft-water projects often solve this by using buffering substrates and carefully planned remineralisation rather than generic tap water management.
Rising nitrate tells you about feeding, export, plant uptake, and stocking pressure. It is one of the best practical signals for whether your routine scales with your aquarium.