I have been struggling all year with good control on the weeds. The question I have is, is the volume to chemical rate correct. EG I use a 200gal tank Its calibrated spraying 3 gallons/1000sqft. Trimec as an example. Top end rate 1.5oz My formula would be 200g/3gall per 1k = 66k of coverage multiplying that by the product rate of 1.5oz gives me 100oz of product for the tank mix. Correct right? My weeds look terrible, and this is the top end. Am I missing something?