Well I had to draw your attention somehow,...
I am experiencing these days white growth on some of my plants - here's the rotala rotundifolia green. The picture is not as clear as reality. The edges of the new leaves are white, sometimes half of the leave is white.
So what is it? calcium deficiency? potassium "toxicity"? iron deficiency? micros deficiency?
Other parameters: NO3=13, PO4 = 1.3, PH= 6.5, KH=5, GH=5, 12 ml flourish iron + 1 DASH CSM per day, Additional ppms of K+ during water changes, 2-2.5 wpg, JBL substrate that includes peat.
I see such white growth in some of my ludwigias as well. Hygro sunset leaves are not wrinkled though.
What I did last: had yet another "great idea" to lower GH, also added more ferrous iron, less CSM iron, more potassium. Was out of town for a week.