I don’t see a problem with that. I would encourage you to draw a sample EVERY DAY to make sure it still looks good. At a pH of less than 2 i don’t see anything being gutsy enough to grow in there. However, stuff happens and that’s why you should look at it daily just to make sure no one poured a soda in there, or a quart of oil…etc.
What percentage of oxalic do you mix? Do you own a refractometer?
