Laundry detergents mixed with bleach always remind me of laundry days when I was a kid,Ha,Ha,...
You know,..The Vinyl Siding Institute actually recommends using Tide or other laundry detergent with bleach for washing siding,..Not sure how credible they are but either way,..it's what they recommend.
Laundry detergent is actually a pretty good option,..especially on basic house washes where only mild detergent is needed,..which is most cases.
For those who use laundry detergent,..just put it in a different container and put on a chemical formula code,..just don't forget what's in there,Ha,Ha...
Not sure about the liquid Gain,..but the powdered Gain has a serious detergency factor,...I found that out from doing laundry with it and the clothes I wore made me itchy,,.which to me means harsh. It must have a high PH because it will even darken raw wood like high PH wood strippers do.
I used the powdered Gain a few times on house washes and it worked well. But Purex is cheaper and works as well. I use about 3oz. of Purex and about 3 liquid oz. of 9% SLS (Sodium Laury Sulfate),.. in a a 5 gallon bucket of DS mix along with 1 1/2 gallon 12.5%. Run through a 3-5 GPM injector and 150'-200' of hose. Makes soap like mad and cleans very well,...and customers love the delicate smell along with seeing all that soap on the windows when they're inside watching. Little more rinsing but not bad,...plus,..I also like seeing lots of soap.
If I get into a house that is really dirty and not just moldy,..I will replace the Purex with Sodium Hydroxide,..cuts bug crap and regular outside dirt better,..but usually isn't needed. Used more in spring and Fall when temps are down.
Jeff