I would do a little of what each of the guys are saying. Clean out your tank, take a small pump sprayer with apple cider mix and re-treat. Should come clean after that. Make sure the mix sits on the roof for at least 15-20 if its a weaker 6% strength before rinsing.
hello,my name is Nick.Im not here alot but from time to time I surf and read, and learn from here.I dont do to many roofs but have done a few.Listen,my buisness is a complete property management company as well as pest control.Since I have read about your stain,and you used a pest control tank with brown stains,I would guess it was iron sulfate which is used to green up grass. Rust aid out of home depot might work for you, or some erase off from Lesco.If you havent resolved the problem give that a try.
That sure looks like sodium hydroxide to me. I doubt the pesticide stain from the tank would cause that, but who knows. Just make sure you buy your SH from someone who knows what they are doing. I sure wouldn't get it from a local hardware store, as it has probably been there for awhile and isn't very fresh. What did you use to apply the chems? It almost looks like the soot output after you turn on a hotbox that hasn't been fired up in awhile. Did you use the delevan?
I mixed up a small batch of SH & water giving a final mix of 35% SH. I used a pump sprayer and applied to a small area. I waited 30 minutes and rinsed. STAIN GONE! I used the remaining mix and cleaned as much of the stained area until I ran out of mix. Waited and rinsed with same results. I had planed on finishing the cleanup this afternoon but it has started raining. I'll finish the cleanup once the rain stops and post some final pictures.
I checked with the manager at Ace Hardware and he confirmed he was selling SH. His tank was refilled 2 days before I purchased.
I am pretty sure the pesticide residue was the problem. I was told when I bought the tank used that the stain was permanent. Lession learned. Never take someone elses word and ALWAYS clean a used tank before putting into service.
Glad you had a better turnout,but I have to ask the rig you bought did it come with the tank and hose,and if so did you use the same hose that came with the tank'
I think you said you only use about 4 gallons the first time, and that makes me think that the first thing to come out of your hose would be the left over mix/brown stain.
Charles, I feel your pain. I just cleaned my first roof and it did not come clean. I almost had a coronary and am still worried. (See my thread "Getting Started") I am glad it worked out for you. Your expierience gives me hope! Patrick
Don`t ever sweat it until you have sprayed the roof 3 or4 times. I saw a gray roof turn black the first time it was sprayed with love, it`s like invisible algae but it came clean after 3 sprays.
In the 20 year i've been in the roof cleaning business, I have never had a roof that didn't come clean. Some needed more love than others and some a lot less. The bog secret is ....PATIENCE....... Given the proper dwell before applying additional chemical will not only save you $$$$ but will allow the chemical to remain on the roof . Waste makes Haste!
Thanks to all for the help and encourgement. Here is picture after I used a pump up sprayer to get the last of the stain. I plan to redo the front section using my 12 volt pump. Then it will look as clean as the section over the garage.
Congrats so what was the problem you just didn't put down enough LOVE I see or wasn't strong enough I guess lesson learned is WE might have to spray more than one time ??