SunSun Hw303B 370GPH Pro Canister Filter Kit with 9-watt UV Sterilizer

The Sunsun Hw 303B is great. Just finished setup in my marine tank. Read the reviews and tips. Mostly about using silicone lubricant (do not use Vaseline it will dry out the seals and crack them use silicone food grade lubricant only) on all the seals and purchased some of that as well. Turns out the company must be listening because all the seals were already lubed sufficiently from the box. Setup went very well with no leaks and it’s very quiet. I had modifications I had to do and the parts they supplied for the send and return were just what I needed with some careful thought. Be careful if you need these parts the cheaper ones may not come with them. They are less expensive because they don’t include the various nozzles, hoses and fittings.The only glitch I ran into was a big one if I hadn’t had some experience with these filters previously. The pictures I have supplied show the indicator for the uv light. This is what shows you the light is on or off. It’s just a plexiglass shaft that goes from the light chamber inside to the top of the unit. 1st pic shows it (circled in red) on the inside. It should be flush to the bottom of that area. 2nd pic shows it topside(again flush to the top surface). This piece was not in the proper position and would not allow the inside glass cover for the UV light to properly seal at the bottom or as in pic 3 the lock to properly engage fully. It took some doing to get it into its proper position but it finally popped in and allowed the glass cover to seat properly and the lock (shown in pic 3 circled in yellow) to fully engage over the flange of the cover. Had I not seen this it could have sent water into the light chamber and outside of the unit, frying the light and possibly shorting out the entire thing. Maybe worse since water and electricity don’t have a history of working well together. 4th pic is the final setup. I put a bin under to catch water in case of leakage as some suggested but so far it isn’t needed. It’s dry as a bone.Short of that I’d definitely recommend this unit for a small tank but take your time with setup, think things through and watch a few YouTube videos to avoid the pitfalls.Update as of 1/17/2024 :Still running well and zero leak issues. UV still functioning as well. Has developed some noise. It’s definitely noticeable but tolerable. Tried all the fixes recommended for canister filters on Google and YouTube to no avail. May try replacement of the impeller. Otherwise it’s performed diligently.Update 4/30/2025. Still going strong. Zero leaks the whole time. Never got around to replacing the impeller either. Still at the same noise level and I’m okay with it.

I’ve been a fish tank enthusiast for 30+ years. In the past I owned many different canister filters including some well known pricey brands and I would have to say this one is by far the best. I have absolutely no negative things to say only positive. It’s easy to maintain it keeps the water crystal clear and the best thing about this affordable efficient filter is how ultra and I mean ultra quiet it is. I bought it over a year ago and it runs and sounds the same as when it was new. The first night it did make a little bit of noise and I thought I would have to return it but when I woke up the next day I had to check to see if it was still running because it was so silent. I definitely recommend purchasing one for yourself you will be happy.

I love this filter! I use it for an aquatic turtle. I’ve had MANY filters over 30 years and this is the best one yet!

This is a well designed canister filter (303b), using perhaps less robust materials than I have grown accustomed to. Instructions are next to useless. Poor packing decisions led to significant cleaning prior to use. All that said, I do think it is a solid product. I pulled a star, I think not unreasonable for a good product that comes with a little hassle.Out of the box, the internals were very dusty due to poorly bagged ceramic media being packed inside the filter during transport, which is possibly the dumbest thing I could think of. Lots of rinsing of extremely fine dust later, especially around the impeller and the rubber sealing ring (recommend re-application of a plummers silicone grease to the ring if yours requires similar cleaning, or if you are leaking around the seal between the top and bottom pieces of the canister itself, this is likely your culprit.)Once past that, the rest of the setup was pretty easy. I love the amount of room for media there is. I see in other reviews here how many are setting their media in strange orders... this type of filter runs the water from the bottom up, so you want the mechanical floss stuff on the bottom (course bottom, fine top), and the biologic or chemical medias should be on the higher trays. I personally used only mechanical in the bottom tray, bioballs and ceramic in the second tray for beneficial bacteria, and the final level is bagged Purigen, only 50% full to maximize fluidic contact.Filling the canister with tank prepped water until all media was covered before locking up the canister made priming pretty easy. After about 30 seconds working with the priming button, I had good flow going, plugged it in, and done. No leaks, no fuss. I have a fine ear especially for electronic hums and the ilk, I have to put my ear within a foot of the unit to percive any hum after the usual sputters of air have cleared. UV light worked, a nice benefit... 24 hours of use a week should be plenty enough for its percieved benefits, and will greatly lengthen the life span of the bulb.If this sucker keeps going with the right maintenance for a few years, I'm going to feel pretty pleased with this purchase.