BaO-B2O3-Na2O ternary system is of great importance for growing crystals of low-temperature modification of barium borate (beta-BaB2O4) widely used in nonlinear optics. Discordance in the interpretation of phase equilibria impelled us to address it again. The investigation method used were spontaneous crystallization on the platinum loop, visual polythermal analysis, solid-state synthesis, X-ray power diffraction, X-ray structure analysis, Raman spectroscopy, differential thermal analysis and chemical analysis. New solid state triangulation scheme was suggested based on the existence of NaBaBO3 compound. Liquidus surface of partial ternary system BaB2O4-NaBO2-NaBaBO3 was investigated. New compounds NaBa4(BO3)3 and Ba5B4O11 were identified and structurally characterized. It was shown that the appearance of scattering centers in BBO crystals strongly correlates with the increased content of Na. Crystals grown from depleted sodium system BaB2O4-NaBaBO3 have great advantage concerning crystals quality.