# Fluval FX4, FX6 to replace two SunSun's



## Linwood (Jun 19, 2014)

Well, no real interest? 

Here's some info from my outcome if it is of interest.

I got the FX6, new, from Amazon. it costs about what three of the SunSuns did.

On the good front in comparison: 

- It was at least as quiet as the two SunSun's, maybe a bit more quiet. It is audible in a quiet room in the open, but not audible with the sides (plywood) on my stand.

- It was easy to set up and worked fine out of the box.

- I replaced two SunSun 404B's each with a spraybar, with a tee and one FX6. The flow rate, by eye, was actually a bit higher from the FX6, consistent with the gph ratings. A bit unfair comparison as it had clean media, though the SunSun's did not slow down much over time.

- The "smart" pump is rather neat. I had quite a bit of air in it at first (trying to get all the plumbing straight), and it would run a bit, stop to let air rise, run a bit... worked fine, flushed all the air nicely with no need to prime.

- I had been told the media was very specialized and I would need to buy only Fluval media, but really it's pretty simple shapes to cut out of bulk material, and you can arrange it in lots of easy combinations.

On the "worth noting but didn't matter to me" front: 

- The included tubing, intakes, and outlet seemed cheap and flimsy just like the SunSun's, but I make my own from vinyl tubes and PVC, so no matter. I'm really not a fan of the Fluval ribbed tubing.

- There is some implication that the third port on the device is used for draining the canister prior to cleaning. Well, you can, but only onto the floor. I just THOUGHT that the pump would be used for pumping out water. Not so. That takes a special kit that's optional, which is mentioned on the Fluval site but in about 10 minutes of looking just now I cannot even find the kit. But it holds only 3-4 gallons of water so it's not a big deal to carry. Might be a big deal to some.

On the bad side: 

- Not sure yet about the seals on the removable in/out nozzles. With the super-secure-looking screw down lid, the plastic push-on snug-fit seals on these seem a bit iffy.

- The media capacity is tiny considering. One media tray was filled with about 2/3rds of the contents of Matrix from ONE sunsun. There are three such trays. The media in the outer ring (course sponge) is fairly large, but the space for bio media and fine/floss pads is miniscule compared to two SunSun's. Now that's not terribly important as with a heavily planted tank I am not counting on bio media in the filter, and do not use chemical media. If you want a lot of room though -- this is not it, considering the flow rate.

- The in/out are 1" hose. Almost. I bought 1" ID vinyl, and it fit other 1" bibs perfectly, but these were quite loose, and required VERY tight hose clamps to keep it from leaking, tight enough I worried I would damage the plastic. Would be fine with the weird Fluval hose if you use it. Marginal for regular 1" vinyl, be cautious in attaching.

FWIW. Now to get rid of three of the SunSun's (I think I will keep one for emergencies).


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## bharada (Mar 5, 2004)

I hope that your FX6 won't fall into the case of 'they don't build 'em like they used to' but I've been running an FX5 on my 120 for almost 10 years. Except for the little orange pivots of the lid clamp screws cracking on two of the screws it has held up like a champ.

As with you I never bothered with any of the factory Fluval hoses or tubes.


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## Linwood (Jun 19, 2014)

Yours is much prettier than mine as I decided not to redo all my 3/4" tubing and pipe, and instead put the 1" T and associated vinyl and valves on top of the FX4.

This time i did something I really should have before -- I put a ball valve in ever line coming from the tank, so I could (separately from the filter's valves) turn off any line if there are leaks, a need to change filter types, etc.

And never thought to put a light under the tank -- that's interesting. And I have a spare LED+. Hmm...


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## Patriot (Dec 22, 2010)

I just got a FX6 today. The difference was noticeable after only a hour of it running. I had a 4 stage SunSun that's still connected to the 80 gallon tank.

The water is clear! It would be nice if the fluval held the same amount media the SunSun does. 

I wanted to removed it and only rely on the FX6, but the SunSun is connected to the CO2 reactor. 

Once I get the hoses swapped out I'll get rid of the SunSun probably.


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## rightwinger59 (May 22, 2017)

*Intake/Outtake Connections?*

I'm going to resurrect this thread, so my apologies, but I was wondering how you ended up connecting your vinyl tubing to the intake/outtake mechanisms that came with your Fluval? 

I just got an FX4 for an 80 gallon tank that I'm setting up, and based on numerous other threads maligning the ribbed tubing (combined with the fact that I'll be connecting the return line to a large UV filter) I want to swap the Fluval hosing for thicker black vinyl tubing. Got some 1" tubing at a LFS and it fits pretty well on both the in/out valves on the top of the filter and to the intake/outtake mechanisms provided.

My main question, though, is how you looped the vinyl tubing up and over the edge of the tank, as the vinyl tubing (especially the 1" variety) is not nearly as flexible as the Fluval tubing and won't fit around the clasps provided to attach to the back of the tank. Did you end up using elbows? Or should I just think about making a PVC delivery system and use barbed fittings/tubing where flexibility is needed?

Thanks.


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## FishEggs (Mar 19, 2017)

I did pvc down to a barbed fitting for mine.

Bump:


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