Which ink does the Epson EcoTank Pro ET-5800 use?

The EcoTank Pro ET-5800 does not take cartridges at all. It is fed by Epson 542 bottles, one each of black, cyan, magenta and yellow, which you pour into tanks built into the side of the machine. There is no chipped carrier to click into a carriage, so the part you buy is just ink in a plastic bottle.

That changes the running cost more than anything else about the printer. Each 542 bottle is rated at about 6000 pages and lists near $25, which works out around 0.42 cents a page, and since all four bottles cost the same, a page that uses all four colours lands near 1.68 cents. For comparison, take the 24 Epson cartridge printers in our database and find the cheapest black cartridge each one can use: the middle of that group sits at about 3.82 cents a page. The ET-5800 runs its black for roughly a ninth of that. You pay for the saving up front, because a tank printer costs more to buy in the first place, so the machine earns its keep only if you print enough pages to get that money back.

Epson does not lock this model with firmware and the bottles carry no chip, so the printer has no mechanism to check what you pour in. Epson states that position for EcoTank in writing rather than leaving it to be inferred, which is more than its cartridge models get. Third-party bottles will physically work. The risk sits elsewhere: the print head is a permanent part of the printer, so ink that damages it turns into a repair bill rather than a cartridge you can throw away. If you are going to use non-Epson ink, buy from a supplier that states the ink type matches what the ET-5800 uses, and keep the receipt.

The maintenance box is the part owners tend not to know about. It is a replaceable cartridge of absorbent material that catches the ink spent on cleaning cycles, and when its counter fills, printing halts even though every tank is still full. Epson sells it as a user-replaceable part on this class of machine, so it is a swap rather than a service visit. Disuse causes the other common stoppage. A permanent head left standing for weeks dries in the nozzles, and no amount of ink in the tanks fixes that. Print something in colour every week or two, and run a nozzle check before you blame a refill.