After spending a weekend sanding about 600 sq. ft. of old floors half painted that had nasty old carpet over and half bare wood with even nastier old carpet over and finding 100 year old chestnut below was a really nice surprise. The plan was never to have the look of new hardwood there were 1000s of staples to remove and something like 36 holes where wires and cables came up that we turned plugs to fit and glued in. nicks and such that add to the character of an old floor. Started sanding on the paint with 20 grit and working our way down finer and finer, then filling some of the blemishes and final sanding. Things looked really nice I tested the floor a few places with a damp rag to see how the grain would come out with finish. I was very tempted to put some Danish oil on it and wax it and call it done. But the more we talked it really needed a bit more protection than that. I read up a little on finishes and have used the old type varnish many times in the past and everything I read said the water based poly was the way to go both in smell, drying time and durability. I used it a few years ago on a counter top and hand brushed a dozen coats on it over a day or two and it wore like iron. So thats what I bought. Went to my local center and talked to the expert after watching several on line vids of guys slamming out a room in 5 minutes using a squeegee like tool. I went with the ZAR product and asked the expert if this is the milky white stuff that dries clear and doesnt add a yellow cast like varnish does. He said thats the stuff. I then asked him what is the best tool to get the stuff on a floor and he said no question its these and showed me some very thin and dense foam rollers. I said well I just watched videos that show it being poured on and wiped around and should I be using one of them. He said they didnt even sell such a thing and has sold many of these rollers and thats what he recommends. So I look it over and say ok. I read the can and it says do not roll on with nappy roller and to use a foam applicator and not a brush. I thought that odd as the counter I did I brushed on all those layers and it came out like glass but I have foam and its a roller so who the heck knows. Lets try it out. Starting in the less visible room and stirring the stuff for quite a while I gave it a try. And his information seemed to be spot on. It rolled on effortless went on like milk and by the time I got across the room the first half was clearing up and looked amazing and even the semi-gloss sheen was appearing and just what I wanted. I then brush painted it on in a small pantry that has a lot to cut in and is too small to work with the pole and roller and went on to the main living room and it went just as smoothly as the first room. Finished up and read the can again saying should be dry to the touch in a couple hours light sand, clean and give second coat etc. same thing as I did on the counter and it looked like I had enough material to do 3 coats was my plan. When I inspected the floor it looked beautiful. Only thing I saw was a couple places when the finish brought out the grain it also brought out some old staining of the wood from maybe spills or pets or something but really looked amazing I thought given 100 years of wear. I rigged my drywall sander to take a softer backer pad like a very soft scotch brite pad and then put a fine sand paper over that. Worked well went over all the rooms and felt very smooth to the touch. Second coat same as the first only noticed because the floor was now so smooth it didnt have the tooth for the foam roller to roll effortless over the floor. It required just a little bit more pressure. Second coat went on fairly good and I again hand brushed the pantry room. This time when it dried there were a few places that dried with a whitish cast kind of a cross between orange peel and some air bubbles. It really wasnt bad and I took just a tad more time sanding those places and when testing the white went away when recovered with even water. So I figured the third coat would blend them in fine. Again waited what I thought was more than enough time before doing that sanding cleaned everything good and went at the final coat. It was even slicker to roll on and hard to tell the difference between the white the material is and if it had any foam in it from rolling did the whole floor and brushed the pantry again. As a point of note I actually feel I was putting on thicker coats with the brush in that room. When the final coat dried I had a super lot of the white haze everywhere except the pantry room. So without a doubt the hard foam roller was the culprit. I hadnt thought thru it yet at that point and had hopes that an overnight miracle might occur and I would wake to a crystal clear finish. No such luck. I spent half the day debating what to do on Sunday and seeing the room (pantry) I didnt really care about look the best I decided to go back to the building center and kill the old guy that recommended that foam roller. OK just kidding I did feel like doing that but kept the urge under control. My pole sander wasnt adequate to sand away the smoke like it did after the second coat. I grabbed my mouse sander and 180 paper and tried an experiment on a 6 x 12 area in the less important room in the area that had the most clouds. Took about a hour hand sanding and several sand paper pads and the floor had a white smooth surface. I cleaned it with mineral spirits and sucked the rest up I then cleaned with soapy water and then just a water wipe being careful to not soak anything. When the surface was wet it looked clear and perfect so my hope was a brush coating would keep that look. I redid that area with the brush and let it dry and Im back to good again so I guess I have a plan for tonight for the rest of the bad spots in the main room. I hope my story may help someone else and if I had it to do again it would be get out the knee pads and brush or find a suitable pad and pole applicator. The big difference I see with the water based poly is it skins over so fast less than 10 minutes where oil products take hours and hours. I think trapped air is going to stay trapped. That first coat had the wood below to draw down into and I think thats why the first coat went on so perfect along with the roller was working more like a squeegee because the wood wasnt as slippery as the poly on the second and third coat. I think I will be able to save it but I wish I would have asked the questions first and did a lot more research rather than thinking I understood it along with getting some bad advice from the expert.