Fluval Spec Output Nozzle Mod - Test Results

[RemoGaggi]

I started a Fluval Spec 2.6 gallon yesterday and am using a 80gph pump from Amazon that on paper (and my finger test) appears to be a little stronger than the stock pump.  I'm using the stock output nozzle and stock tubing (7.5 inches long).  I was watching the flow last night and my eyeball test says there is not much movement in the tank.  I have read that the stock output nozzle restricts a lot of the flow.  Some remove the output nozzle (the moveable part inside the tank) and run it naked.  I read one post where the output nozzle was drilled out to increase flow.  This morning I decided to do a quick experiment - Stock Nozzle vs. Naked vs. Drilled Stock Nozzle.

 

I used a 3/16 drill bit on the output nozzle.  Just pull the flat nozzle portion off the ball joint and drill.  I used a 3/16 bit because I think going any larger will deform the flat part of the nozzle.  After drilling, be sure to clean it out really good - there will be some plastic shavings in there.  

 

I put the pump with the stock hose and nozzle in a small bucket of water.  The pump would move the water into an 8-cup Pyrex measuring bowl.  I used the stopwatch on my Ipad to time how long it would take to get it to fill to 8 cups (half gallon). 

 

Here are my results:

 

Naked - No output nozzle, just the stock tubing and the elbow that fits through the false wall.  I tested 3 times with an average time of 40 seconds to get 8 cups.  

 

Stock Nozzle (Unmodified - straight) - I tested 3 times with an average time of 73 seconds to get to 8 cups. 

 

Stock Nozzle drilled with 3/16 drill bit (straight - not angled) - Tested 3 times - Average time of 43 seconds to get to 8 cups.

 

Stock Nozzle drilled with 3/16 drill bit (fully angled) - Tested 3 times - Average time of 60 seconds to get to 8 cups.

 

My conclusions

Clearly the stock nozzle is a major bottleneck as it nearly cuts output in 1/2 from running naked.  The drilled nozzle worked a lot better if ran straight (no angle), but if you're running with no angle, why not just run naked?  Fully angling the output of the drilled nozzle restricts flow.  If you're keeping the output nozzle, I think drilling is mandatory.  I might just drill it out even more, even if it deforms the flat portion of the nozzle.  

 

Additionally, I found it troubling that even running naked, the pump was only pushing roughly 1/2 of the 80gph it is supposed to move. 

 

It should be noted that I did not test the stock pump, which according the fluval website has a lower flow rate than the pump I tested.  I did do a finger test of both pumps by comparing flow by feeling the pressure of the water and my 80gph pump was clearly stronger than the stock pump.  I think I will run my 80gph pump during cycling and then probably upgrade the pump to the Aqueon 600 or MJ 606 down the road.

[Clown79]

Most nozzles cut flow.

Your test is very interesting. Thank you for the info.

 

I have experienced with the fluval specs that their stock pump sucks. Very low gph(the tanks are designed for FW) and they clog quickly.

 

I upgraded my pump to double the output of the original pump. The 5.5g spec comes with an 80gph, I believe it's the same or less for the 2.6g 

 

I have found the rfg nozzles to be great. They add random flow in the tank allowing to avoid a powerhead. 

 

[RemoGaggi]

18 minutes ago, Clown79 said:

I upgraded my pump to double the output of the original pump.

Did you get the Aqueon 600 or MJ 606 or something else?  I've got my Spec on my work desk, so I need it to be quiet.  How do you like your upgraded pump?  And thanks for the tip about the RFG nozzles.  I was looking at those as well.  Sounds like if I upgrade the pump and get the RFG nozzle, I should be set.  

[Clown79]

15 hours ago, RemoGaggi said:

Did you get the Aqueon 600 or MJ 606 or something else?  I've got my Spec on my work desk, so I need it to be quiet.  How do you like your upgraded pump?  And thanks for the tip about the RFG nozzles.  I was looking at those as well.  Sounds like if I upgrade the pump and get the RFG nozzle, I should be set.  

I got the aqueon 600 for the 5.5g. It requires a 2 mins mod and fits.

 

It was super quiet.

 

I really like the rfg nozzles, they have them for the spec. I never got one for my spec because I'm now using the spec for qt only.

But I use them in my 10g and 25g.