Can you test your nitrate and phosphate levels? Might be something lacking or out of whack. 2.5ml of macro fertilizer solution seems very little - without knowing details it's just my gut feel. :fish1:
So applied to planted tanks, if one of the essential nutrients is absent, it won't matter that others are there in abundance, plant growth will be determined by the most scarce nutrient.The availability of the most abundant nutrient in the soil is only as good as the availability of the least abundant nutrient in the soil.