Guar gum needs to be thin enough to make it easier to pump. Then as it flows down the pipe, the fluid needs to gel up to support the proppant and flush it deep into the fractures. After that process, the gel has to break down so we can flow back and recover the fracking fluid, but leave the proppant behind. This requires a chemical process which produces then breaks the gel cross-linking at a predictable rate. Guar+boron+proprietary chemicals can accomplish both of these goals at once. Guar gum retards ice crystal growth nonspecifically by slowing mass transfer across the solid/liquid interface.
Hydrochloric acid between 20% and 32% are sold as muriatic acid. Solutions for household purposes in the US, mostly cleaning, are typically 10% to 12%, with strong recommendations to dilute before use. In the United Kingdom, where it is sold as "Spirits of Salt" for domestic cleaning, the potency is the same as the US industrial grade. In other countries, such as Italy, hydrochloric acid for domestic or industrial cleaning is sold as "Acido Muriatico", and its concentration ranges from 5% to 32%. Major producers worldwide include Dow Chemical at 2 million metric tons annually (2 Mt/year), calculated as HCl gas, Georgia