Opinions? Fluval 306 vs. SunSun HW-402B

Although the sunsun is cheaper ( I have had both) and the hoses of the fluval are corrugated I think it would depend on what you wanted them for I have running now(sunsun's) 1 for biological and 1 for bio and chemical. The sunsun can hold more media but the fluval are much easier to take care of and quieter.
if money was no object fluval it would be.

The issue I have with these type filters is that they both use lid top pumps which use extraction to pull water from the top where its more susceptible to priming problems on restart. Whereas bottom pump filter is designed to use gravity which helps pull dirty water through the filter media where it is cleaned and free of trapped air before reaching the pump and guaranteed submersion for reliable primed restarts. In addition stacked basket type filters inherent in those top pump designes suffer from very low surface area as each basket surface area being stacked in series is only as effective as the basket it sits behind. Lastly top pump filters operate by pumping water in reverse so that filter media has no positive backing within its basket causing the edges of the filter media to lift up and out of the way of the water current allowing most of the dirt to simply bypass the filter media unless the baskets are over packed tight further limiting performance.
IMHO, round surface area canister filters with powerful bottom pumps like the FX5 and its bargain cousin the Odyessea CFS 500. All my top pump filters are on the shelf dry if anyone wants to buy them. The only canisters I now use are bottom pump type with round surface area media already mentioned including the Magnum360 and Magnum 250. I also use 14 gallon tall aquarium sump filters where stacked basket are far more effective since the utilize both downward gravit and water pressure to trap dirt against the filter media supporter by the basket frame, no bypassing.

Oh...I suppose if I had to pick between those two filters, both of which I own but no longer use for 3 years now, I would use the Sunsun since it seems to be more leak proof, quieter operating, easier to clean, and easier to achieve and maintain prime even on startup. But as far as filtration performance, they both are poor performers IMO.

Wow. I'm shocked that there are criticisms of the SunSuns. I just bought a new 525 GPH model for 68 bucks shipped with some bio-balls, ceramic rings and carbon! I bought it because I'm so happy with the 265 GPH model that I got about a year and a half ago. I run it on a way to over-stocked with turtles 29 gallon. It keeps the water crystal clear with coarse and fine pads on either end and the rest filled with super cheap Home Depot lava rock. Every 2 or 3 months I have no problem disconnecting it without a drop of water misplaced and a simple rinse and squeeze of the pads. It's not even worthy of the "chore" title. The UV is actually a feature that I've come to like. I turn it on about a week a month and algae is really kept away. Never had a problem priming it and it is completely silent. For bigger tanks in the future I may use the SunSuns in conjunction with a sump. I just don't see any need to spend so much more for the "big" names in filtration. The only HOBs that I have are ones that came on tanks that I picked up off of Craig's List. I only keep them around as back up in case of a failure and to set up an aquarium quickly if I want fish before a new SunSun would arrive.

I just bought the Sunsun 303B for my 37 gal. it has a flow rate of 370 GPH. Seems like a pretty solid filter with three large media baskets. I like that it has the built in UV light which I will use from time to time. This filter is real quiet and the price is hard to beat.

I have fluval 205, clean one or two times of year, no leak no problem.
Is silent but don't suggest keep in bedroom.
I non't like made in china

wow this is a hard one, i have both sunsuns and fluvals running, if your tight on money get the sunsun, they do what they are said to do, the down fall is no bell or whistles, the fluval has better media, better pipes, and a more solid and tough construction. the sunsun works but if your not careful you can break parts. the only thing i hate about the fluval is the impeller top plate, they are pron to have the clips break, so be careful if and when you pull it to clean, also make sure you LFS can replace these for you, it would suck to have to pay shipping and go through all the BS to get a $10.00 part
BG

if you decide on the sun sun I'd recommend a mod to the pick or intake side.. they use cheap sectioned fittings that can draw air and the filter stops due to a break in the siphon. I replaced the sectioned part with spare hose from the feed lines .. now there's no siphon break and the filter is easier to start up or will continue to run during a water change