The paper aims to provide an initial assessment of the potential for phosphorus (P) and nitrogen (N) removal from wastewater by two underexplored algal strains, Vischeria helvetica ACUS 00025 and Klebsormidium nitens ACUS 00207. The experimental setup consisted of two 4.5 L open photo-sequencing batch reactors (PSBRs) operated at laboratory scale for three months using secondary effluent from a full-scale municipal wastewater treatment plant. The comparative analysis showed that Klebsormidium nitens strain had more consistent results for all parameters throughout the experimental period: i) higher biological phosphorus removal for Klebsormidium nitens (1.02 ± 1.66 mgP∙d-1) than for Vischeria helvetica strain (0.25 ± 0.55 mgP∙d-1); ii) higher nitrogen removal for Klebsormidium nitens (1.254 ± 1.84 mgN∙d-1) than for Vischeria helvetica (0.66 ± 1.61 mgN∙d-1); iii) Klebsormidium nitens showed superior stability in monoculture, with increased resistance to contamination by other algal strains and consumption by other heterotrophic organisms, a shortened wastewater adaptation period, and consistent settling properties via autoflocculation. Both strains maintained relatively universal conditions favourable to effluent and water quality after treatment. These conditions include an average pH of 8.2 and 8.63 and an average DO concentration of 8.48 and 8.85 mgO2∙L-1 respectively. The results are particularly important given the paucity of data in the existing literature on the specific technological parameters required for algal bioreactors.