How Do I Stop My Ministers from Buying Goods I don't need?

[GenPatton43]

Its killing me. I had all of my production lines cranking but as of late I have two issues.
Coal Manufactured: 1,541,729
Coal in Use: 1,240,420
Backstock:39,000,000+
However, everyday I end up in the red like now: Yesterdays trade= -1,077,354

Same goes for Industry Goods
IG Manufactured: 72,780
IG Actual Use: 68,669 (Building more coal mines atm)
Backstock: 826,006
Again, in the red. 4,139
I have my "Sell Surplus Production turned all the way up to 100% and both items are being sold around 21% profit, yet it looks as if they are being sold for less then that or a minister is buying more then I need and the difference comes out into the red.
Is it just a matter of continuing to build more facilites for those in the red or can it be regulated?

[Meisseli]

Have you tried to lock minister out from commodities? Just pick a commodity and press that little lock button near upper right corner

[GenPatton43]

Have you tried to lock minister out from commodities? Just pick a commodity and press that little lock button near upper right corner

Yes I have. I am doing right by having the slider under "Bulk Purchases" turned all the way down to 0 correct? Is there something else besides that?