Hi, I'm Sean.
I made salz.run for me.

I'm a trail runner with a 50K this October and a first 100K penciled in for 2027. I'm not fast, I'm not sponsored, I'm not coaching anyone. I'm just a guy who likes long days in the mountains and is willing to suffer to finish what he started.

I'm also a heavy sweater. The kind where my shirt is crunchy with salt after a summer long run and my eyes sting two hours in. For years I bought the fancy electrolyte powders (LMNT, Skratch, Precision, the works) and watched my training budget bleed out at $2 to $3 per serving. As the weekly volume ramps up toward the 50K and beyond, that math gets ugly fast.

One Sunday I looked at the back of an LMNT packet, then at a $9 bag of potassium chloride on Amazon, and the gap was absurd. So I sat down with a 0.01 g kitchen scale and a few sports-science papers and worked out my own formula: five cheap ingredients, weighed by the gram. It works better than the pre-mixes (because it's calibrated to me) and it costs about a quarter per bottle. That calculator is what this site is.

The current training picture

Outside of running I ski (alpine when I'm at a resort, backcountry when the snow and the weather and the legs all agree) and I'm extremely good at sitting around the house. None of those things will get me to the 50K start line, let alone the 100K. The training will. And the training only goes well when I don't blow up from under-fueling in the heat (or, in winter, when I bonk halfway up a skin track because I forgot to eat).

What this site is and isn't

• · It's a calculator. Plug in your numbers, get a recipe. The math is open; the constants are in the footer.
• · It's a notebook. The blog is where I write down what I'm trying: protocols, mistakes, papers I've read. Slow and salty.
• · It is not a coaching service, a supplement brand, or medical advice. If you have hypertension, kidney disease, or take potassium-sparing diuretics, please talk to a doctor before you add extra electrolytes to anything.
• · It is not trying to be a business. The Amazon links on the kit page (five ingredients plus a kitchen scale) earn me a few cents per click. That's the whole monetization. If the site never makes a dollar, I'll still keep mixing my own.

Method & replacement targets

Replacement targets in the calculator are deliberately conservative. I'd rather undershoot than send anyone to the hospital for over-drinking.

The big risk in endurance hydration is exercise-associated hyponatremia: low blood sodium from drinking too much water. It kills people. Slight under-replacement is mild and self-correcting; over-replacement plus over-drinking is the dangerous one. The targets above keep most adult athletes in the green zone in most conditions. Drink to thirst.

Get in touch

If you find a math error, a stale citation, a weird edge case in the calculator, or you just want to talk about trail running, please write. I'll fix the bug and credit you. I'm a real person, not a chatbot.