Fluval Fx4 And Biomedia Capacity

Hello Everyone!

Quick question about the capacity of the FX4's media capacity

Background Info:
I was running 2 Marineland C360s and got sick of them constantly sucking air from who knows where and blowing bubbles.making noise, etc. I have a 40gal tropical tank with a Fluval 306 and love it - so when looking for a replacement for my two 360s I was looking to Fluval.

I was thinking about the 406 but the FX4 will actually fit better (weird right, the shorter height helps in my cabinet).

Anyways, I was only able to stuff less than half of the biomedia from my two 360s into the fluval, and that was with removing one of the red trays to get a little more room...
For reference I am running this on a 75gal Cichlid tank with about 20 fish in it, mostly Malawi, they range from 2.5-5" at the moment.

So, a few questions:


-I left the biofoam, inside the red basket on the top level - should I remove this an replace with my media (BioHome Ultimate)? And is this safe to have loose media (even though its large and sshouldn'tmove...) exposed on this top level?

-Does this think hold enough bio to handle a highly stocked Cichlid tank? I know I am running it way below its '250 gal' limit, but these fish are dirty/big eaters as you all know
I have a sponge filter in there right now but I would like to remove it at some point, it takes up a lot of room and I would like to get rid or air pump and just use the filter output to move the surface enough for air exchange at some point.

- in the very bottom tray I am running chemical (Chemipure and Purigen) as well as some EHEIM Substrat Pro media (in a bag since some of the beads are small lol) I am not used to bagging bio media, would I be better off swapping this for Biohome sticks in there instead? Worried about flow through the bag filled with beads...

I think that's it for now - info on this filter seems pretty sparse out there so if anyone has any questions/needs pics, measurements etc let me know!

Thanks


Oh - and a pic! (old pic before I installed the filter, but its dark in there at the moment
)

 

I also run a FX-4 and I was not quite sure how the circulation went untI now. So the FX-4 filters from the sides first hence those big foam things, then it gets sucked in from the top down. I figured this out because like you I use Biohome Ultimate and I had my media going like this before........

Top- I kept the black Bio foam then I put a bag of Biohome Ultimate underneath the black foam and then in the second tray(I also took out both of those red trays) I had another bag of biological media and then pinky filter and then filter floss.

Now jump a month or so and I had to clean my filter.....

What I noticed when I first took off the cover and then the black foam was that my Biohome Ultimate was just full of junk and muck and just going down it got a little cleaner.

So now I have my set up like this........from top down.........

First tray

Black foam-coarse
I also had pond foam that I purchased before so I used it like this.....
Blue foam-a little less coarse
Gray foam - fine
Then I use media bags as it is easier for me to just grab them when cleaning.....
Biohome Ultimate

Second tray-top down

Another bag of biological media this consists of Eheim substrate pro and Sera Siporax
Pinky filter media
Filter floss
Purigen

This is my current setup and how I place things in my FX-4

Good Luck!

 

Thanks for the reply! I got how the flow went, but still need to look at it closer to see how they prevent bypass, seems like water could easily escape from the outer foam into the center - but like I said need to look closer

I ditched the red tray in the bottom one because I could not get them to nest together with it in place, I was probably stuffing to much bio material in there, but without it it fits together

Do you find that this is a sufficient amount of bio material for you? Maybe I am just used to more - and maybe I am under a false impression that you need TONS of bio to support enough bacteria... Just seems so strange that this filter is rated for 2.5x what the c360 was and holds half the bio, but kills it on the mechanical front.

Do the outer foam sponges work as bio too - at least to an extent?

 

I do think that the outer sponges act as a Bio filter also. Plus all of the internal space that is inside the filter.
I think that Biohome Ultimate is a little big for the space that Fluval has in those baskets. And that's why I use the other biological media. Substrate pro and Siporax are a lot smaller than Biohome but I really like Siporax and use that in some of my other filters along with Biohome Ultimate.
My water parameters are always good and I never have had any problems with water parameter issues.
I use my FX-4 in a 33 long that is pretty stocked and I also have 2 royal Plecos, Bushy nose, and clown. Plecos always make a ton of waste and I have never had any water problems.
I have to add that I do have a Seachem Tidal 55 on that tank also. On all my tanks I have at least 2 filters and a hydro sponge filter, so I do over filter all my tanks.
So in short I guess I can say that what I have in my FX-4, I feel is sufficient for my tank.

I hope this helps

 

Thanks I will be keeping an eye on things for sure, especially while this new filter gets established, I moved seeded media in but I am sure it still disturbed the system balance
Maybe I will give up on my idea of removing the sponge filter - just to add another layer of bio...

 

It is kinda disappointing on how small the Fluval FX-4 area is for biomedia. Somehow if they could have maybe made the outer sponge area smaller and maybe somehow made the baskets deeper or wider that would have been great.

Good Luck and try and get some Seachem Stability to help with your Bio media it's a great product IMHO

 

Thanks! And ya, I was kind of blown away, on paper it sounds great (1 gal of bio cap) but once you get everything else (chem too) its not much room Hopefully all that sponge area will help and I run sand too so that should be packed with bacteria.

And yep, I run Stability, have some more on the way too haha.

 

I am glad to hear that you already use Stability! I think it's a great product! Just a little info for you.......

I have a 33 long in which I have my FX-4 and my substrate is Seachems Black Onyx Sand and it is almost just like sand. Make sure not to put the intake too close to the bottom or you can like how I did put a small piece of foam in the bottom half of the intake strainer so that if Sand gets kicked up it doesn't get into the filter. I don't have any big grains but what I have found in my filter is this fine silt and I rinsed my substrate really good or so I thought.
Sand and impellers don't mix and match. And unlike the FX-6 which has some sort of super impeller the FX-4 still has the regular looking impeller just a little bigger than normal. And make sure that you know the part that attaches the tubing to the canister itself that elbow looking piece that has the flow control on. Make sure that you push it all the way down, I was super lucky and when I first got my FX-4 I only partly pushed it down it was kinda hard to push and I didn't want to break my brand new filter, but I was only a bump away from the thing coming off and unloading all my water onto my floor. It still worked and didn't leak I guess the suction was strong enough along with the rubber o-rings not to make it leak. But that's something I will always remember as this is my first FX type filter I ever used.

Good Luck and Thanks!

Brandon

 

HAHA! I did the exact same thing! Luckily it had a tiny leak when I fired it up that showed me the error of my ways! Ya, you have to REALLY push on those to get them to click in place.

Good to know on the sand, I have ~4 inches between the sand and intake at the moment, but that's not to say I haven't seen my fish pick up a mouthful of sand - swim it over to the intake - and spit it in!!! Crazy fish...

Checked my numbers yesterday and sitting at 0-0-30 so looks like I still have enough bio to handle the load. Whew, will be keeping a close eye on it for a few weeks till I am confident it settled. I have one of those Seachem ammonia alert things too, never seen it change color but from what I hear they work great so I keep my eye on that as well.

 

My Fish are crazy they have rescaped almost the whole tank. And especially at the end where the output is. That's how I get that slit in my filter. The output is strong enough to carry all that silt to the opposite end of the tank where the intake is.

Funny! When putting those things on, I was so worried about breaking that thing. It's a ticking time bomb for someone who doesn't catch it and it decides to leak when they are away.

I always wondered about that ammonia alert thing. It's good to know that it works! I think I will try one out and see how it does in my tank.

I think your tank will be ok! MAYBE just maybe 1 water change could help that nitrate come down and stay down.

Good Luck!

 

Ya, no kidding, I couldnt believe it when it was leaking because I was sure I had them in all the way, ,fair warning to whoever comes across this thread in the future! Mine also rescape...everything - I never get it how they like it I guess lol

And ya regarding the nitrates I have been fighting with them, my water already has them and I don't want to go through the hassle of using RO water. I made a cobbled together Nitrate reactor out of a fry tank that hangs off the back and has a very small/slow pump, only been on for a week or so, excited to see if it works - I am seeding it with stability now and then. I was up over 80 the other week when I measured it right before a water change! Maybe I was feeding to much. Did a 50% water change then and again a few days later to get it down to 20 or so - didnt want to shock them with to much more of a reduction than that all at once.

I do a 35-40% change once a week and that seems to keep things stable, but they are growing fast and I need to pay more attention to my water params since I am overstocked...promised myself no more, only if one dies I have only lost 2 in the 2 years I have been running this, one was just to small I think, he lasted a few weeks then they got bored and tore him to shreds one day... The other was a yellow lab that was more pale than my others since I got him - he lasted about a year - I think he had something up with him from the start.

 

I also run a FX-4 and I was not quite sure how the circulation went untI now. So the FX-4 filters from the sides first hence those big foam things, then it gets sucked in from the top down. I figured this out because like you I use Biohome Ultimate and I had my media going like this before........

Top- I kept the black Bio foam then I put a bag of Biohome Ultimate underneath the black foam and then in the second tray(I also took out both of those red trays) I had another bag of biological media and then pinky filter and then filter floss.

Now jump a month or so and I had to clean my filter.....

What I noticed when I first took off the cover and then the black foam was that my Biohome Ultimate was just full of junk and muck and just going down it got a little cleaner.

So now I have my set up like this........from top down.........

First tray

Black foam-coarse
I also had pond foam that I purchased before so I used it like this.....
Blue foam-a little less coarse
Gray foam - fine
Then I use media bags as it is easier for me to just grab them when cleaning.....
Biohome Ultimate

Second tray-top down

Another bag of biological media this consists of Eheim substrate pro and Sera Siporax
Pinky filter media
Filter floss
Purigen

This is my current setup and how I place things in my FX-4

Good Luck!

Really pleased I found this as had my FX 4 running for 2 weeks now and had it set up like mt APS 2000.
Apparently the wrong way round for FX 4
Will be sorting it out Sunday (Water change day) 10% change weekly
500 Litre tank
ph7
Nitrite 0
Nitrate .25
20 Buenos Aires Tetra
10 Rummy Nose Tetra
10 Cardinal Tetra
10 Black Skirt Tetra
6 Albino Cory
2 Bristle nose Plec