Sealing grout with 511 Impregnator, second coat

Is it advisable to put a second coat on grout joints using 511 Impregnator? I noticed on the can the statement that "a second coat may be necessary for some surfaces". I am only going over grout joints (about one hour's work this afternoon) but I had a difficult time determining if I was getting sealer on all of the grout (the clear sealer just did not show up real well on the grout joints). I ended up using a toothbrush to brush the sealer on the quarter-inch grout joints.
My project is a very small bathroom with a tiled floor, partially tiled walls and a tiled shower. I sure want the shower to be well sealed and wonder about a second coat at least in that area. I have some sealer left and I am considering brushing some more on the grout joints? I also wonder if a second coat 24 hours after the first coat is the acceptable.
Your comments and opinions are welcome.
Thanks, Terry
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My wife does 2 coats of AquaMix grout sealer annually in our tile shower and two coats on the countertops.

BTW, she uses a real boar bristle paint brush (which has better absorption/carrying properties IMO than a nylon toothbrush)
We do use 511 as a sealer on our granite island.
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see if water beads up?
snipped-for-privacy@mn.rr.com wrote:

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