Hi DGman i have been using Drytreat for over a year running tests against the other known sealers in my case as most of my work is on listed buildings i need to be sure otherwise big fine or worse.
I found it was easier to use as the cleaning off is simple i haven't had problems with patches getting tacky as has happened with other sealers and it allows the tiles to breathe which as most of my work is over lime screed is very important.
I tested it using a tank the middle of the tank had a piece of granite fitted this was sealed with stain-proof and filled with water the lower half had air pumped in under pressure, no water dripped through either with a granite bed or local red sandstone however the pumped air went through and bubbled up into the water.
I'm happy it does what it says and have used it to eradicate efflorescence and am in the process of getting the process validated with the likes of Historic Scotland and other heritage organisations.
Plus if an approved applicator puts it down it gets a 15 years warranty.
Cheers Steve