Can someone help me with my math? I want to reach a target of 1 ppm. KH2PO4. The wet calc said. 14mg of dry fertilizers. How much would I need to put in 500 ml to make a concentrate that when I pump it in I reach the same as dry? My tanks are all different volumes so I need this to be a general solution.

Your question is hard to understand...I don't understand what you are asking? you already answered your Quest..

Now if you are asking how much to dose ml wise than calculator will give you the exact amount but you have to specific: your tank size matters.

E.x: 14.69g of Po4 to 500ml water and dose 30ml 3X week to get 1.3ppm target.

If you want a general solution so that you can use it on all volumes you could add 1mg per ml. You will still need to figure ppm for your individual tanks but you'll always have 1mg/ml for liquid measurement purposes.

I mix 1 cup of water (236 ml) with 5 teaspoons (24 grams) of KH2PO4.
This solution will dose 0.93 ppm per each ml mixed into 20 gallons of water.
(compliments of Rex's webpage yrs ago)

http://calc.petalphile.com/

this is so simple that you don't even need to ask those questions.

take whatever grams you want /lets take 5g/in 500ml water.PO4 in KH2PO4 is 69,8%
so [(5x0,698)x1000] / 500=6,98mg PO4 in each one ml of this solution.
If you want to add 1mg/l PO4 in 10g/38,7l/ water(for example)- (1x38,7)/6,98=5,54ml of this solution.
hope this will help

How many total gallons of aquariums are you dosing?

What is your starting phosphate?

Use wkndracer's recipe and dose as needed.

Thank you everybody for answering my question. Not everybody can do it without a little help. Some times the question isn't always clear, because we aren't sure exactly how to ask the question. So when people take the time and are nice about their responses it makes the hobby and being on this website a pleasure.