I've had 2 other guys in the last few years have the same issue of grass browning when using F9. It was a technique issue with both. If you have followed the instructions as laid out, just make sure to spray from the grass line inward toward the concrete (don't spray grass directly). You should be able to control the product as to not drench the grass with F9. This should solve browning issues with F9 BARC. A little bit in the grass won't burn it, and if you do get a more than a little and the grass Browns, it will come back in 4-7 days.
As for Pressure Pro Clearly Pink, I have been given an MSDS from one of our F9 Team Applicators.
This product is an EXTREMELY HIGH concentration of Hydrofluoric and Sulfuric Acid. I think you will always have issues with this chemical's aggressive attack on plants, skin and body. All I can say is make sure to wear all PPE, faceshield etc when using and wet, wet, wet the grass and surrounding areas. Carry calcium gluconate with you at all times be careful.
Do a google search on HF and Sulfuric acid burns to see what why I am adamant to use extreme caution~
To answer the question on temps, the weather really doesn't have much of an effect if you are using F9 BARC for rust removal. I formulated this to work in high heat and am out in 100+ temps all week. 111 yesterday and supposed to reach 115' today.
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