Fluval Flex Owners - Experience, Mods, Advice

[SaltwaterandLime]

If you’re having a problem with the hood bowing in the center just loosen the front screws on the front light. This solved my problem.

This worked for me also!!

 

[JNoyes1026]

This worked for me also!!

Sweet hint!!!!

 

[evan47]

I have the same tank and love it so far. I upgraded my return pump to the sicce syncra 1.5 which fits perfectly with no mods. I also have 2 of the inTank media baskets. For powerheads I bought the Current USA duel wave pump kit with controller for like $130 and it is working well for me. I like how I can mount them to the back glass and angle them back towards the middle. I think my blue and purple lights top out around 75% and my whites are around 15% and everything has been extremely happy. In fact with the lid on so tight, I didn't even need to add any water for 6 weeks, and still have not done a water change since I started it. My tank does get up to 81-82 though because of the tight fitting lid.

When you fitted your powerbeads how did you route the cables? Are there already holes for cables in the lid or did you need to alter the lid at all please? I am thinking of getting a new tank this year and the flex 123 looks great.

 

[Lsuhunter]

The middle chamber has a gap that all of my cables go thru(2 lights, heater, return pump, uv sterilzer, temp controller, 2 powerheads, doser tube). It is about an inch tall and the width of the chamber( 3 or so inches).

 

[ecswanson213]

If you guys had to pick one would you do a power head to increase flow or upgrade your pump. I am having a little issue with Cyanobacteria right now and one of the things people suggest is increasing flow.

 

[Fishyj]

I would say powerhead for flow. I replaced my pump for heat issues, it didn’t increase flow that much.

 

[kpoj9]

If you guys had to pick one would you do a power head to increase flow or upgrade your pump. I am having a little issue with Cyanobacteria right now and one of the things people suggest is increasing flow.

Unfortunately, flow isn‘t going to fix cyano issue.

 

[hworner]

I have a fluval flex 15 in my first chamber I have the intank media basket with filter floss, activated carbon, and ac bio medium. Was wondering what to run in the 2nd chamber and also a good return pump to upgrade to!

 

[Tweeter173rd]

I pretty much did what scubafish did.
First thing I upgraded was to the intank media tray, since the stock sponge one didn't do much as far as flow. Highly recommend since now, the water flow from the intake, up to the baffles and then back down again so I can layer me media. I use filter floss, carbon/chemiclean, and then finally some ceramic media for bio filtration. Kinda expensive at $50 per media box.

I also had an extra hang on back breeder box and made myself a hangon refugium with an ebay grow light.

I also bought the icecap k2 nano for my protein skimmer.

I sold my light that came with the fluval flex and bought 2 ai prime 16hd.

Im going to keep my pump since I put on 2 jebao slw20. They are super powerful, im only on 20% power. I decided to get 2 since I wanted the swaying motion for my torches that I currently have in.

How are your AI primes working on this? Im in the process of trying to get rid of 3.0’s, want to open up the top to help with Ph a bit. I only have about 8” of clearance above my tank though, so I’m bouncing around with what seems to be an endless back and forth from Radion, Hydra or Primes...It’s annoying. Seems that I have 2 Primes as the frontrunner option.

 

[jmwils1]

Has anyone found a maker for an acrylic/mesh top? neither kraken nor clearview offer one. I’d like to get rid of the hood but have some jumpers..

 

[Fishyj]

Has anybody figured out better filtration on these tanks. I have replaced the return pump and power head that I was using but still have scum on the surface.

 

[Lsuhunter]

The bottom intakes are the scum issue. The filtration is pulling more water from the bottom of the tank instead of the top. There is a guy on facebook marketplace that 3d prints covers for them so all of the water is pulled from the top. My issue got much better after I added them, only problem is that he lives in the UK so it takes a couple of weeks for them to come in. Look up 3deep.

 

[fachatga]

I got rid of the top and made a mesh one so I could use t5 hybrid with red sea 50 led. I also use a carbon gfo reactor about 12 hours a day because I don’t like how any filtration system in those rear chambers were using. I’ve also for 2 wavemakers on either side for better flow. Hygger 1600. I run one on 60% and the other on 40%. I like the tank but it’s hard to modify. But then again it’s fun to think of ways to get what I want. My skimmer is aquamax. Was the best I could find they fit. Good to see the other options people here found in case I need to remove it. I use the rinse ato in the back corner of the tank. Made my lid so it goes around it. Nobody can jump out the tiny crack that’s left unprotected. I like this conversation tho. Wish I saw it to give me ideas before I started messing around. Was a great tank foe me to start off with because it was up and running immediately. But once I got really serious about the hobby it does need some improvements.

 

[Fishyj]

Looks nice, can’t get rid of my top because of a very Curious cat. She gets into everything. Thanks for the information on the lower intakes .

 

[fachatga]

I’ve got cats too. The large hanging light fixture over the tank keeps them out. Otherwise if have wet cats and dead fish lol. If it was just a few led lights it wouldn’t work and they would go swimming.

 

[BTimms]

I got rid of the top and made a mesh one so I could use t5 hybrid with red sea 50 led. I also use a carbon gfo reactor about 12 hours a day because I don’t like how any filtration system in those rear chambers were using. I’ve also for 2 wavemakers on either side for better flow. Hygger 1600. I run one on 60% and the other on 40%. I like the tank but it’s hard to modify. But then again it’s fun to think of ways to get what I want. My skimmer is aquamax. Was the best I could find they fit. Good to see the other options people here found in case I need to remove it. I use the rinse ato in the back corner of the tank. Made my lid so it goes around it. Nobody can jump out the tiny crack that’s left unprotected. I like this conversation tho. Wish I saw it to give me ideas before I started messing around. Was a great tank foe me to start off with because it was up and running immediately. But once I got really serious about the hobby it does need some improvements.

How did you make the mesh lid? I’m looking for a similar solution.

 

[fachatga]

Brs website has do it yourself kits

 

[Davos2911]

Has anybody figured out better filtration on these tanks. I have replaced the return pump and power head that I was using but still have scum on the surface.

I had the same issue. I bought an eheim 350 surface skimmer. The surface scum disappeared within a few hours.

 

[tmoneylee71]

there is a small gap between the bottom glass and the plastic “wall” than divides the small outer chamber and the return pump chamber in both sides. This gap bypasses the filter - both stock and intank baskets

Did you have to empty the tank to fill these gaps

 

[ecswanson213]

Has anyone tried the Fluval autofeeder? What are people using for autofeeders?