Elegoo Resin Tank Empty Warning — Refill Guide

What Does This Error Mean?

Most Elegoo printers don't have an actual resin level sensor — the 'tank empty' warning usually means the printer has been running long enough that you should check the resin level.
Pause the print, look in the vat through the safety window, and add resin if it's low.
Don't pour resin while the printer is exposing — wait for a non-exposure moment to top up.

Affected Models

Elegoo Mars 3
Elegoo Mars 4
Elegoo Saturn 3
Elegoo Saturn 4 Ultra
Elegoo Jupiter

Common Causes

Resin level dropped below the safe printing line
Long print exhausted the initial vat fill
Failed print left less resin than expected
Resin remaining is heavily pigmented and hard to see (false alarm)
On Saturn 4 Ultra and newer: real ultrasonic sensor reading low

How to Fix It

Pause the print.

On the touchscreen, press Pause.
The build plate will lift to its rest position and stop exposing.
Wait until the plate has stopped moving before opening the lid.
Open the lid carefully.

Lift the cover off the printer.
Don't tilt or shake — any drips off the lid go right onto the LCD.
Set the lid down on a paper towel.
The printer's UV light is interlocked off when the lid is up, so safe to look in.
Check the resin level.

Look at the side wall of the resin vat.
The resin should be at or above the MAX line marked on the vat.
If it's lower, top up.
Use the same brand and color of resin that's already in the vat — mixing brands is risky for cure consistency.
Pour slowly and to the MAX line.

Tip the resin bottle gently against the inside of the vat.
Pour slowly to avoid bubbles.
Stop at the MAX line — don't overfill, and never go above the metal frame.
Wipe any drips off the rim with a paper towel.
Resume the print.

Close the lid.
Press Resume on the touchscreen.
The build plate will descend and exposure will continue from where it paused.
Watch the first few layers after the resume to confirm everything is moving correctly.

Frequently Asked Questions

Can I top up resin while printing without pausing?

On most Elegoo models, no — the lid interlock would have to be defeated, which is unsafe.
The safer approach is to pause, top up, and resume.
Pause time is included in print time and your model won't suffer from a 30-second pause if you're careful.

How do I know how much resin a print needs?

Most slicers (Chitubox, Lychee) show a 'resin used' estimate before you start the print.
Check that estimate against your remaining resin in the vat plus what's in the bottle.
For long prints, fill to MAX before starting and top up at planned pause points if needed.