Fertilizer stock solution

[joe_orch]

I am making a stock solution of 20-20-20 to make 32 gallons of working solution. I am shooting for 125ppm N. The formulas state I should use .48 tsp. of fertilizer to make 1 gallon of working solution. I figured to multiply .48 x 32 for the stock solution, which figures to 5.12 tablespoons to 1 gallon for the stock solution, which I also added 5.12 TBSP of Pro-tekt. to get the working solution to a ph of 6.5. I use 4 oz. of stock to 124 oz. of RO water to get my working solution. When I test my working solution the tds reading is 181 ppm total which seems low to me. Am I figuring this right? My TDS meter is calibrated to the proper TDS reading of 1382.

Thanks for the information,

Joe