It is well known that most Be stars are photometric long-term variables, and that at least two characteristic behaviours can be recognized when simultaneous photometry and optical spectroscopy are available: positive and inverse (negative) correlation between the Balmer emission strengths and the stellar brightness (Harmanec, 1983). Indeed, a positive correlation has been observed in several Be stars as their Hα emission gets stronger when their photometric V magnitude increases:
Harmanec, P., 1983, Hvar Observatory Bulletin, 7, 55
Juza, K., et al, Astrononmy and Astrophysics Suppl., Vol. 107, p.403-411 (1994)
Koubsky et al., Astronomy and Astrophysics, v.328, p.551-564 (1997)
http://www.bav-astro.de/rb/rb2011-1/5.pdf
http://www.bav-astro.de/rb/rb2014-2/89.pdf
http://www.bav-astro.de/rb/rb2012-1/20.pdf
https://konkoly.hu/pub/ibvs/6101/6109.pdf
Obviously this is also applicable for pi Aqr. The attached plot (top) shows the Hα EW developement from JD 2456868 (2014/07/29). The plot bottom shows simultaneous V data (AAVSO data base) versus Hα EW (BeSS spectra) from Oct. 2014 to Oct. 2021. The current visibility of pi Aqr invites to take spectra in order to complete the correlation.
Ernst Pollmann