The ELW-3M is definitely the better option. It has built-in wifi, allowing you to control it using the Jebao app on your smartphone. This gives you more control over the wave patterns, flow rates, and schedules.
The ELW-3, on the other hand, does not have built-in wifi. You would need to use a separate controller to adjust its settings. This can be less convenient and less flexible than using an app.
The advantages of the ELW-3M I found was it was easier to control because you can control the wavemaker from your smartphone, even if you're not near the tank. It's also more flexible because you can create custom wave patterns and schedules to suit your specific needs.
as well as the Jebao app offers a variety of features, such as the ability to monitor water temperature and salinity.
The ELW-3M is a bit more expensive than the ELW-3, but the added convenience and features are worth the extra cost, especially for a beginner.
Also to consider the ELW-3M has a flow rate of 660 gph, which is suitable for a 15 gal tank. I use two in a 25 gal tank and are extremely easy to use.
The ELW-3M is also relatively quiet as well.
Overall, id say the ELW-3M is a great choice for a 15-gallon tank. Let me know if you end up giving it a shot! :)
