Most whom grow blyxa inject Co2. Since it is a green plant may be able to get it to adjust with ferts as suggested. Ludwiga will turn green if it doesn't have enough light. Sometimes can get it to turn bronze with iron which is in the tabs.Blyxa was kinda hurting though. I think it was an algea issue, not sure though. we will see.
That is probably what is causing the algae then. Plus may be going through a cycle. This reminds me of someone whom had green water in a tank whom had MTS substrate. The plants weren't affected thus he just left it alone and it went away in time.I think with the dirt in there, there is a lot of extra nutrients.