Wet & Forget dilution math?


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Old 04-17-24, 06:46 PM
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Wet & Forget dilution math?

Anyone use Wet & Forget to get rid of algae / moss on decks, siding, concrete?

Can someone check my math.... the wet & forget in the concentrate bottle is 9.9% of the active ingredient? Mix it per the label 1 part to 5 parts water and you get a 1.65% solution for spraying.

Costco sells the hose end product now, not the concentrate. That's got 30% of the active ingredient. So that means you have to mix 17 parts water to 1 part of the hose end product? Seems more cost efficient compared to the old product? / concentrate.
 
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Old 04-18-24, 05:09 AM
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It all depends on the price you pay.
 
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Old 04-21-24, 08:55 AM
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Ed -

I used Wet and Forget on my asphalt roof shingles to get rid of lichen and it worked great. I see how you got the 9.9% for the concentrate (I used the concentrate myself), but I don't see how you got the 30% for the hose end product. I couldn't find the concentration for the hose end at the Wet and Forget web site and didn't find the hose end product at all at Costco. Maybe staring me in the face though.

But it does look like the hose end product is a lot more expensive per ounce than the concentrate. If I'm looking at the right stuff however. I might consider the hose end product myself. I have one of those backpack sprayers. I filled it up with Wet and Forget and it almost pulled me backwards off the ladder -lol! (But my bad - could fill it half way I guess).But it does seem to work very well.

I do think however, it is as Pilot Dane says, in the end it would all come down to price.


 
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Old 04-22-24, 12:02 PM
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Here's a pic of the hose end product price from a costco in NJ. This and last year, at least in NJ, I only saw them selling this hose end sprayer. Before that, they sold 2 bottles of concentrate.

The MSDS for the hose end says 30% (and I called W&F and they've said it's 30% in the hose end spray container). I know it is MUCH thicker than what came in the concentrate bottles we bought in previous years at costco (here in NJ).

Hose end MSDS (see section 3)
https://www.wetandforget.com/downloa...d_03282022.pdf

Concentrate MSDS (see section 3)
https://www.wetandforget.com/downloa...t_03282022.pdf

So from that pricing pic:

$30 for 68 oz of liquid, which is 68* .3 = 20.4 oz of 100% of the chemical = $30 / 20.4 oz = $1.47 per oz of chemical.

I thought I had a pic for the concentrate in the past, but can't find it. On the web:
https://www.costco.com/wet-%2526-for...100338171.html

So lets say $27 in the warehouse for 192 oz of 9.9% = 19 oz of 100% of the chemical = 27/19 = 1.42 per oz of chemical. (and thinking - It was on sale back then,,,, $20?

Oh! So it's more expensive for the hose end sprayer! Yes, like @pilotdane was thinking... gotta do the math : )

Now bear with me. We were at a Canada costco and bought HTH algaecide 15% of the same chemical in wet & forget. Paid $29 CAN for 8L of 15%. There's 13% tax up there! So that works out to about $24 USD for 270 oz of 15% = 40.5 oz of 100% chemical. that works out to 60c US per ounce!

Side note - when we were at this costco, they had chlorine pucks. I texted a friend who has a pool and he says the prices up there are much cheaper, even when converting currency.

so you can bring back $800 / person with no duty? Is chlorine pucks allowed through?


And again, check my math.... based on the dilution ratio of the concentrate, I get a 1.65% of chemical for the ready to use solution. So work backwards with a dilution calculator for the 30% hose or 15% HTH product.

https://www.tocris.com/resources/dilution-calculator

(I don't quibble with the units of measure. Just put in 9.9 and 1 for concentration 1. and 6 for the volume of concentration 2. Clixk calculate and you get 1.65 for concentration 2's strength.




 
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Old 04-23-24, 10:32 AM
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example: calc for oz-ADC

Ed -I was a little confused on the calculator, not sure of the exact product to use. But anyway, the picture above summarizes the way I do the calculation. It seems to work for those of us who get the wrong answer a lot of times. It's more mechanical.

Did it for that link to the 2 bottles for $32.99.
 

Last edited by zoesdad; 04-23-24 at 10:46 AM.
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