Quick DIY flow reducer for fluval flex tanks (or any tanks with nozzle-style filter outputs)

[HenryC]

Absolutely love fluval flexes, but their pumps are kind of powerful for such a small tank. My betta and neons get blown away all around and struggle to remain calm, plus the food gets all scattered and sometimes end up outside the fish's range of vision.

This is a quick DIY, cheap flow reducing method I managed to come up with. You can do it too with things you, being a fish keeper, most likely have lying around. Just 2 pieces of sponge and some zip ties. You just have bend around the sponge peices around the nozzles and zip tie them in place, then cut excess tie. Can even "control" the flow by slightly sliding around the pieces of sponge! Hope you find this useful.
 

 

Edited September 17, 2020 by HenryC

[Travis]

I just added this in my Fluval Spec. The original outlet went from 1/2 inch to two 1/4 in outlets just like what you have in yours I believe. I felt like it was jetting current across the tank hitting the end and rolling. My new spray bar is all 1/2 ID and spreads the flow out more evenly. I also was having an issue with the 1/4 outlets getting plugged up a bit over time. Im hoping the larger ID helps

[amr427]

Same thing is happening to me with my Fluval flex 15. I bought this mod spray bar on Etsy that said it was low flow and since it has way more holes that the original attachment I thought it would help. Not sure it does.

The pump was making a weird noise so I took it apart to clean it and of course that increased the flow more.

Going to try the sponge idea on the mod spray bar.

Wish Fluval made the pump adjustable😑

[xXInkedPhoenixX]

I have a flex9 after getting advice here on the forum. 

Fluval Flex series anyone?

I also have the flow bar that @amr427 has from the same seller more than likely. It worked great for reducing flow. However I ended up having to buy an new pump from amazon because the original pump took a dump on me and I couldn't figure out why. So thankfully I found one that fit AND that has a flow controller. Because the original equipment failed I also added a small Hygger sponge filter to the 1st chamber that has a back up lithium battery so if the power goes out the tank still has some filtration. It's likely at a small disadvantage being behind the wall but something is better than nothing. I also put the original flow nozzles back on because of the new pump.

But to the theme of this post- I like my aftermarket pump better- I can control the flow. 

Edited October 5, 2021 by xXInkedPhoenixX

[amr427]

On 10/5/2021 at 10:50 AM, xXInkedPhoenixX said:

I have a flex9 after getting advice here on the forum. 

Fluval Flex series anyone?

I also have the flow bar that @amr427 has from the same seller more than likely. It worked great for reducing flow. However I ended up having to buy an new pump from amazon because the original pump took a dump on me and I couldn't figure out why. So thankfully I found one that fit AND that has a flow controller. Because the original equipment failed I also added a small Hygger sponge filter to the 1st chamber that has a back up lithium battery so if the power goes out the tank still has some filtration. It's likely at a small disadvatage being behind the wall but something is better than nothing. 

But to the theme of this post- I like my aftermarket pump better- I can control the flow. 

Please share the link for the new pump you found that fits!

[xXInkedPhoenixX]

@amr427

This is the Hygger sponge filter I put in the back chamber:

https://www.amazon.com/gp/product/B07XZ831WR/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1

and this is the pump I found for my 9:

https://www.amazon.com/gp/product/B074QMHRPW/ref=ppx_yo_dt_b_asin_title_o03_s00?ie=UTF8&psc=1

[amr427]

On 10/5/2021 at 10:59 AM, xXInkedPhoenixX said:

@amr427

This is the Hygger sponge filter I put in the back chamber:

https://www.amazon.com/gp/product/B07XZ831WR/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1

and this is the pump I found for my 9:

https://www.amazon.com/gp/product/B074QMHRPW/ref=ppx_yo_dt_b_asin_title_o03_s00?ie=UTF8&psc=1

Thanks! Read through that entire other forum you linked to, so helpful, love this community!

[xXInkedPhoenixX]

@amr427 that it is, very helpful! We all have knowledge that can fill others' needs and experience. 

[amr427]

Posted this on my journal page but thought I'd share here too. Found this pre-filter and did the trick to reduce the flow!

[teambedell]

I purchased this reduced flow adapter off of Etsy, from FishGuildCorp. It works, due to distributing the flow in multiple directions; but, it actually must allow for more water movement. You’ll notice that chamber 3 (out-flow) of the sump is slightly lower than chambers 1 & 2. The pump is powerful enough to draw the water slightly faster than its flowing into chamber 3 via gravity. It’s stable and staying where it is now, but it’s important to make sure the tank is full so the intake is mostly submerged. I think I’ll put the original outlet back on if I’m gone for extended periods of time. Also, chamber 2 was low also when I first noticed it. Topping off the tank solved that.

[fishboi]

Also had this problem with this my Fluval Flex 9; the flow was way too strong for my guppies, nevertheless a betta.

Fortunately, had an old sponge filter laying around and was able to jury-rig it similar to @amr427. I'm fairly certain it's this exact filter, available on Amazon for less than $7 (link below): AQUANEAT Double Bio Sponge Filter (small). Unfortunately, I got it second hand though, so I can't 100% confirm...

The sponge/intake for the filter conveniently fit right into the outflow, diffusing the flow. And water is still pulled into the back chamber, at a much more reasonable rate. Cheapest and easiest option IMO; I also tried ziptying sponges over the nozzles with little success.

https://www.amazon.com/Aquaneat-Sponge-Filter-Aquarium-Accessories/dp/B08S2PDCBR/ref=sr_1_6?dib=eyJ2IjoiMSJ9.BT54MgDQ9lfxXXgJ8CWn2yeFmL3T2CESbQBLFJty8F5u1AjttiNXCcYhuJocZpiemwpv_ocmbeGwp6LKGjEX6i8cxW-fwSK6MXikQghORnKsRuO7KYXjcCN6perep9SWky9fI-56TmFZKKUsbz0Rj4zzi6Ul3mt3vyFNI-ctIb-dJsolm9LG7M4HTVeCbbDDsaGP7U6Qw5cvbeyu8F5HvRmXlNxP7yNrPr8PVgTzQMzHBzc0aSSntL3uxTmuP2loUNX6OWcF40s23GI9xoff9H2AvyVuUTQSk0Y52AB58sQ.lsA9ZKUbZ4f2mUPnZzDqmAi2kETd0DPYaUUyWG0bvS8&dib_tag=se&keywords=AQUANEAT%2BDouble%2BBio%2BSponge%2BFilter&qid=1710268161&sr=8-6&th=1