Grohe has a special tool that is used for installation that comes with the faucet. You have to remove the pullout spray and remove the curved neck of the faucet by pulling out. Insert the tool in the main body and tighten from above. Most plumbers will keep this tool when installing. I don't know if Grohe still uses the same system still today, but they did in the past.
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Grohe has a special tool that is used for installation that comes with the faucet. You have to remove the pullout spray and remove the curved neck of the faucet by pulling out. Insert the tool in the main body and tighten from above. Most plumbers will keep this tool when installing. I don't know if Grohe still uses the same system still today, but they did in the past.