The great thing about canister filters is their quietness and ability to filter large amounts of water.

The downside is they can be prone to leak, are more expensive, and can be a chore to clean. This is why it’s important to select a good quality filter to minimize those issues.

Today I want to compare a couple of popular canister filter brands. The Fluval FX 4 and the SunSun 304b.

We’ll start with the Fluval FX4.

Fluval Canister Filter, FX4 Filter (250 Gal)

Fluval FX4

Fluval has upped their game recently in creating a canister filter with better design and construction. The FX4 is huge and powerful. The flow rate is a healthy 700 gallons per hour.

These are a bit pricey. Average cost is around $265.

There are several internal media baskets that hold the various types of media. I think the space that the inner trays take up is sort of wasted space and could have been used for more bio media. In my opinion, the unit comes with far less bio media than you would need for a 120-gallon tank.

You may also find the top lid fasteners a bit of a hassle. You have to unscrew them all to remove the top lid, but this design creates a much better seal, so totally worth it.

It’s also self-priming which is great. Better than having to manually prime the filter.

Overall, it’s really well designed so that the water flows through all of the media for maximum filtration and water clarity. They’re really quiet units and you can literally go a whole year without cleaning it. Check out the latest price on the Fluval FX4.

Sunsun HW-304B 525 GPH 5-Stage External Canister Filter with 9-watt UV Sterilizer

SunSun 304b

If you’re looking to go the budget route, the SunSun 304B is a good choice. Just keep in mind that the cheaper price comes at a cost. The parts won’t last as long.

For the most part, SunSun is a great filter for the money. The average cost is around $105.

It comes with a built-in UV Sterilizer, but you have to be careful because the UV light could melt the plastic if kept on too long. Also, the light burns out pretty fast. Many people don’t even use it.

The SunSun is also a little noisier than the Fluval, but overall much quieter than a hang on filter.

It doesn’t have self-priming like the Fluval so you’ll have to manually prime the pump after maintenance. Not so much of a hassle.

The flow rate is 525 gph so if the standard is to turn your water 4 times per hour, then it would work for a 120-gallon tank.

Leakage may be a problem if you don’t assemble it correctly after maintenance so make sure you have a proper seal when reassembling. It has 4 latches on top which is better than the older models that only have 2.

You probably want to replace the bio media that come with the unit. What you get are plastic bio balls which don’t do a great job. There are better media out there. It comes with four fine floss filters which is a bit puzzling given that you should have a coarse, medium and fine for proper mechanical filtration.

So in the end, it kind of depends on what your budget is. If you can afford it, then the Fluval FX4 is going to be the one to get. It’s so powerful and will last for years. If you’re on a budget, the SunSun is a decent choice.

Check out the latest price on the SunSun 304B.