Planted tank dosing, in grams.
Dry salts are the cheapest way to feed a planted tank and the most confusing. Fert Lab turns the method you picked into the spoon or the bottle.
WHAT IT DOES
- Real water volume from the glass, minus hardscape and plants, plus filter
- EI, EI low light, PPS-Pro or your own weekly ppm targets for NO3, PO4, K, Mg and Fe
- Steady-state maximums from your water-change percentage, so you know the ceiling
- KNO3, KH2PO4, K2SO4 (for the potassium balance), MgSO4 and trace mix (CSM+B, Plantex, DTPA, EDDHA) in grams per dose and per week
- Solution mode: grams per bottle for a millilitre dose, how many weeks a bottle lasts, solubility check, preservative note
- Weekly plan you can tick off, with macros and micros on separate days
- CO2 from KH and pH with a chart, the pH-drop method, and what pH you need for 30 ppm
- GH booster: calcium and magnesium salts for a target dGH at your Ca:Mg ratio, whole tank and per water change
- Centimetres and litres or inches and gallons, backup and restore
Who it's for
Planted tank keepers moving from bottled ferts to dry salts, and anyone who has stared at a dosing calculator that only handles one salt at a time.
What you get
- Fert Lab (one .html file, runs in your browser, offline)
- A 2-page quick-start guide
Good to know
- One file. No install, no account, no subscription, no internet needed after download.
- Your data stays on your computer. Export a backup any time; import it on another machine.
- Built for a computer screen: Windows or Mac, in Chrome, Edge, Safari or Firefox.
- Instant download.
What's inside the download
- Fert-Lab.html
- Quick-Start-Guide.pdf
Made by Matthew Busel, a one-person studio in Tuckahoe, NY. About me. Questions: support@tensorust.com.
Making and hobbies
Fert Lab
planted aquarium dosing calculator: EI and PPS-Pro dry salts to grams or a solution, weekly dosing plan, CO2 from pH and KH, GH booster
Your tank's real water volume, then EI, EI low light, PPS-Pro or custom ppm targets turned into grams of KNO3, KH2PO4, K2SO4, MgSO4 and trace mix, either as dry doses or a bottle of solution with a millilitre dose. A tickable weekly plan, CO2 ppm from pH and KH with the drop-checker logic, and a GH booster recipe.
Works or I fix it. If a file doesn't open or work as described, email support@tensorust.com within 30 days and I fix it or send a working copy. All sales are final, so check the screenshots or ask first.
- Updated
- Oct 2026
- File
- ZIP, 257 KB: 1 HTML app, 1 PDF
- Who it's for
- Planted tank keepers moving from bottled ferts to dry salts, and anyone who has stared at a dosing calculator that only handles one salt at a time.
One-time price in US dollars, checkout by Stripe. After paying you land on a page with your download link. Each link works for 15 minutes, and reopening that page makes fresh ones.
- Fert-Lab-Planted-Tank.zip