You do  not maximize cooling ...

You do  not maximize cooling water cycles of concentration by starting with the blow-down valve and working backward on treatment or pretreatment.  One begins with the source water, and consider what must be done to render the water benign corrosion tendency  toward metal, and stable in regard to forming scale.  You may consider such things as "chemical sinks", essentially high pH zones where a cathodic electrode increases local pH enough to precipitate group II metals, calcium and magnesium as carbonates, and/or silicates.  You may consider high efficiency softening of the water then close the blow-down so the silicate residual climbs to 100-200 ppm, protects the steel with a nano-atomic layer of silica, SiO2, possibly the best corrosion inhibitor ever designed for steel.

You may consider not doing much to pretreat the water, and pay for it heavily in high tech polymers and corrosion inhibitors, but only after running software projections (or have it done by professionals), where the scale forming tendencies are predicted ahead of time, thereby creating a best operational window.

You may consider losing heat transfer, in which case, the company will or should fire you, and will be out untold quantities of capital cleaning or replacing damaged equipment.