# Z Sub Ohm 2021 tank, coils and upkeep today > The Geekvape Z Sub Ohm 2021 tank, figures cross-checked, which Z and Z XM coils to fit now, the UK 2 ml rule, filling and upkeep step by step. The Geekvape **Z Sub Ohm 2021 tank** is no longer the model the brand puts forward, and newer tanks from the same family have taken its place. Anyone still running one sees the same questions arrive as it wears. Which coil to buy, what wattage to set, how to fill it without a mess? Listings online do not always agree, so this guide separates what is confirmed from what is not. ## The Z Sub Ohm 2021 tank at a glance The **Z Sub Ohm 2021 tank** is a Geekvape atomiser 26 mm wide and 42.5 mm tall, built for direct lung vaping. It runs on the brand's Z series mesh coils, fills from the top and takes its air through an adjustable inlet at the top of the tank. Several shops still sell it under the name Zeus. | Detail | Figure found | Agreement | |---|---|---| | Width and height | 26 mm and 42.5 mm | Two retailers | | Capacity | 5 ml with the bubble glass | Two retailers | | Coils in the box | Mesh Z at 0.2 and 0.4 ohm | Two retailers | | Draw | Direct lung | Two retailers | | Airflow | Top, adjustable | Two retailers | | Mouthpiece | 810 drip tip | Two retailers | Two listings we checked show it out of stock, at least in black, and Geekvape now presents the Z Subohm Tank 5 and the Z Fli 2 in its range. Keeping yours in good shape is therefore a matter of coils and care. ## Which coil fits the Z Sub Ohm 2021 tank The original tank takes Z coils, and that is where its working life is decided. Two generations now share the same fitting, with wattage ranges that change from one listing to the next. ### The original Z coils The box held a 0.2 ohm Mesh Z coil and a 0.4 ohm one. Both retailers we consulted agree on 70 to 80 W for the 0.2 ohm. For the 0.4 ohm, one gives 50 to 60 W and the other 60 to 70 W, a 10 W gap that matters to the wick. When in doubt, start at the bottom of the more cautious range, 50 W for the 0.4 ohm, and climb in steps of 2 or 3 W. Lukewarm vapour and flat flavour point to too little power. A burnt taste points to too much, and the coil often keeps the mark. ### Z XM Boost coils, the compatible successor Geekvape now sells its Z XM coils in a Boost version, and its own page states that any device that takes the Z coil also takes the Z XM, since the fitting is the same. Your tank is not tied to the coils that came with it. | Z XM Boost coil | Range stated by Geekvape | |---|---| | 0.15 ohm | 70 to 85 W | | 0.2 ohm | 70 to 80 W | | 0.4 ohm | 50 to 60 W | One shop lists a 0.15 ohm Z series coil at 80 to 90 W, whereas the Z XM version stops at 85 W. Go by the range stated for the coil you actually fit, on its packaging or from the manufacturer, not the one for a neighbouring model. How resistance, wattage and draw fit together is covered in our guide to [coil ohms and wattage](/uk/vape-coil-ohms-and-watts/). ## When to replace a coil in the Z Sub Ohm 2021 tank The official Z XM page gives a figure to work from, a coil life of around 50 to 60 ml of e-liquid depending on use and PG/VG ratio. It is a rough guide rather than a counter, because the state of the coil matters more than the volume vaped. Three signs point to a coil near its end. The flavour dulls or turns burnt with the wattage unchanged, the vapour weakens at the same setting, and the cotton visible through the wicking ports darkens clearly. A very sweet liquid generally gums up the wick sooner, and the 50 to 60 ml mark then arrives earlier. Changing the coil at the first of these signs remains the simplest rule. Swap it with the tank emptied, then prime the new coil as described in the next section. ## Filling the tank without leaks Filling is from the top. Unscrew the top cap, then pour the e-liquid into one of the openings provided, letting it run down the wall of the glass. After fitting a fresh coil, Geekvape asks you to wait 3 to 5 minutes before the first draw, so the cotton can soak. Then start at the bottom of the stated range. If the tank still weeps, our guide to a [leaking vape tank](/uk/vape-tank-leaking/) helps pin down the zone at fault, seal, coil or glass. The top airflow helps here. The air inlets sit away from the liquid, which limits leaks from the base. ## 5 ml or 2 ml in the UK Both retailers record 5 ml with the bubble glass fitted. They differ on the straight spare glass in the box, 3.5 ml for one and 4 ml for the other. In the UK, regulation 36 of the Tobacco and Related Products Regulations 2016 caps the tank of a refillable electronic cigarette at 2 ml, nicotine refill bottles at 10 ml and nicotine strength at 20 mg/ml. A 5 ml figure therefore describes the international version, not one that can be sold legally here. Neither listing we checked mentions a 2 ml version of this model. In the UK, only a 2 ml glass fits that limit, so check the stated capacity before ordering a replacement. ## Looking after the Z Sub Ohm 2021 tank over time A tank of this generation wears out through its consumables rather than its body. Three habits keep it pleasant to use. ### Clean it at every coil change Use each coil change to strip the tank down and rinse it in warm water, then let every part dry before reassembly. A forgotten drop of water under the coil is enough to cause spitting. Our guide on [how to clean a vape tank](/uk/how-to-clean-a-vape-tank/) sets out the method part by part. ### Watch the seals and the glass Seals harden with time and start to let liquid through. The original box held spare parts, seals included according to one listing. Keep them. A cracked glass can be replaced with a 2 ml glass, the only capacity that complies in the UK. ### Keep the wattage right A mod set too high ruins the wick within a few puffs. If you move from a 0.2 ohm coil to a 0.4 ohm one, lower the power before the first draw, not after. ## Related reading - [Vape coil ohms and watts, choosing right](/uk/vape-coil-ohms-and-watts/) - [Geekvape Z Nano 3 tank, the spec sheet untangled](/uk/z-nano-3-tank/) ## FAQ These five answers cover points that product listings rarely address. ### Does the Z Sub Ohm 2021 take B series coils? No. B coils belong to the Z Nano tanks and the Aegis Boost cartridges. This tank takes the Z series, original or in the Z XM version. ### Can it be used for a tight mouth-to-lung draw? That is not what it is for. Both retailers class it as direct lung, and every Z coil works from 50 W upwards. ### Which mod suits this tank? A mod with a 510 connection that can deliver at least 80 W for the 0.2 ohm coil. At 26 mm wide, it sits flush on a mod 26 mm wide or more. ### Will a 510 drip tip fit? Not directly. The mouthpiece is the wider 810 format. An 810-to-510 adaptor lets you fit one, with a narrower bore as the trade-off. ### Is it a sensible first tank? It is not the one we would recommend. Its coils ask for 50 to 80 W, which assumes an adjustable mod and some familiarity with direct lung vaping already. ## Keeping a Z Sub Ohm 2021 tank in good order Three habits are enough. Fit a Z or Z XM coil and stay within the range stated for it. Fill through the opening provided and give the cotton 3 to 5 minutes to soak. Rinse the tank and check the seals at every coil change. Listings online do not always agree. Read at the source, the **Z Sub Ohm 2021 tank** is simple to look after, and the same method works for any hardware that has left the catalogue, starting from what the manufacturer confirms before trusting the first listing you find. Editorial content for adult readers only. Nicotine is highly addictive, and nicotine vaping products are not for sale to anyone under 18 in the UK. Guide Clearomiseur is an independent editorial title and this article is not a buying recommendation.