I’m new to pressure washing and just stumbled upon fertilizer stains. They have it on the edge of the driveway and all over the back patio. Both are cement.
I realize from reading the forum that F9 is what I’m probably going to need long term for this sort of thing, but at the moment funds are low and I need to get something local that will work.
Can anyone help with a ratio of oxilic acid to water for fertilizer stains? They didn’t run at all, dark brown dots all over so it’s probably going to take a strong mix. Any other basic ingredients (and ready ratios) anyone would be willing to share?
Thanks!
Do you have pictures? F9 and oxalic are SOOOOO far apart. I’m confused. I’ve never dealt with “fertilizer stains” but if it’s organic shouldn’t the SH fix it?
Pictures would help, but im guessing thats not rust. If they are brown dots with no “run” then they are most likely tannin stains (organic stains caused by trees). Use a pump up sprayer with a 50/50 mix of sh/water and apply to the stains.
Fertilizer isn’t organic so to speak. If you do a quick forum search you’ll see lots of chat about it while discussing f9. There is apparently iron and other metals in the little pellets.
They have already scrubbed on it with soap and water to no avail.
Not familiar with tannin stains. There aren’t any trees to cause them though. Literally no trees.
Long chat with the owner. 99% sure it’s from fertilizer Pellets.
When I said it didn’t run, I don’t mean not at all, I just mean it’s very concentrated in one spot, therefore I’m pretty sure very deep.
I got ox for the job because from googling fertilizer stains it was the only thing other than f9 that seemed to have a chance.
Iron can be removed by a chelator. Have you thought of purchasing any CLR from home depot or lowes?
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You said dark brown dots, typically fertilizer stains are orange in color. Again pictures would help. Right now we are shooting in the dark and cant help you with what to use and at what ratio if we cant first determine what kind of stain you are dealing with.
I was looking at CLR. Didn’t know if it was strong enough.
Assume fertilizer. I wish I’d remembered to get a picture. They have the orangeish look you would expect from rust, just darker than a light stain from something like well water.
It’s the iron in the fertilizer that causes the rust spots that as has been noted are generally more orange than brown. Deep brown as has also been identified is usually organic from acorns, leaves etc. SH will remove the organic stains but the orange will require different chemicals. I use Rust Remover Plus and it works great, if you need it “yesterday” some of the other suggestions made here might work in a pinch, just more elbow grease than the F9 or RRP.
You could try oxalic, if it doesn’t work try CLR.
That’s what I thought. Will the oxilic acid work? Instructions say to brush it on at 1 cup ox to 1 gallon of water. Seems low to me but I also don’t want to etch the cement.
Ox acid if its rust. SH if its acorns
1c/1gal works fine and no etching
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