ooooops, I just double-dosed Phosphorus

nah, high phosphates isn't deadly. Some people's phosphates are off the charts and they're still fine. A water change for peace of mind wouldn't hurt though even if it's a small one, but otherwise i wouldn't worry too much about it. just don't dose phosphates the next two times.

How much is triple? I've dosed 9ppm+/week with no issues.

I had just done a 1/3 water change, and was dosing the tank back up, and I put in 5ml in a 10gal tank.

just looked it up using the "Yet Another Nutrient Calculator" and it said I could put in 12ml. That's gotta be wrong?

maybe my math is off?

edit:

maybe it's 12ml twice a week, and then 5ml is ok, I've just never added that much before. I had been following the "beginner" dosage on the bottle. I've been wanting to go to EI anyways

5 mL and 12 mL are not really meaningful, unless we have the concentration of your stock solution.

I assume you're talking about Flourish Phosphorus? 5ml in a 10 gallon tank is only 0.53ppm of PO4. A single full EI dose is 1.3ppm or 12.3ml. Your math is not off. Seachem is simply not very concentrated. That's one reason many people use Dry fertilizers. Not to worry.