Random flow generator for Fluval Evo 13.5

Reef Jockey · Sep 10, 2021

Anyone know what size RFG to add to a dual head on the stock Fluval Evo 13.5 output nozzle? is it 1/4" or 1/2"?

thanks in advance

ScottJ · Sep 10, 2021

1/2". Got mine for my Evo from VCA last year. Works like a charm. I got 6 extra knuckle sections with it, but they aren't really necessary.

aSaltyKlown · Sep 10, 2021

I got two 1/4" that went directly onto the existing knuckles. The main knuckle is 1/2", so you can do what Scottj did. I think most go for the 1/2". If I purchased again, I would go with the 1/2". The 1/4" works but I think it would flow better with the larger.

Reef Jockey · Sep 10, 2021

Thanks Scott and Salty. Im gonna go with the 1/2"

ScottJ · Sep 11, 2021

aSaltyKlown said:
I got two 1/4" that went directly onto the existing knuckles. The main knuckle is 1/2", so you can do what Scottj did. I think most go for the 1/2". If I purchased again, I would go with the 1/2". The 1/4" works but I think it would flow better with the larger.

That's right, I forgot it goes from a 1/2" to a 1/4" knuckle! Yes, one 1/2" generator works pretty good. I used it with the stock pump for a while and had good flow. I switched to a Hygger 260, mostly so I had a back up pump.

Reef Jockey · Sep 11, 2021

ScottJ said:
That's right, I forgot it goes from a 1/2" to a 1/4" knuckle! Yes, one 1/2" generator works pretty good. I used it with the stock pump for a while and had good flow. I switched to a Hygger 260, mostly so I had a back up pump.

So that means if i kept the existing knuckles and just replaced the nozzle, I would need the 1/4" for the dual nozzle and 1/2" for the single nozzle off of the main knuckle "Y"?

aSaltyKlown · Sep 11, 2021

Correct - while the 1/4 inch works I feel it does not disperse as much as it would being 1/2 inch, especially with an upgraded pump. I could be wrong, but it seems like having a stronger pump and the reduction size force the water more and doesn't create a nice wide flow.

ScottJ · Sep 11, 2021

Reef Jockey said:
So that means if i kept the existing knuckles and just replaced the nozzle, I would need the 1/4" for the dual nozzle and 1/2" for the single nozzle off of the main knuckle "Y"?

The knuckle on the wall is 1/2". The Y knuckle must be a 1/2" to (2) 1/4" reducer. So to replace the existing 2 nozzles, you would need (2) 1?4" RFG's.

To go single RFG, get (1) 1/2" RFG, ans a few 1/2" knuckles. Extra knuckles are so you can come out a bit from the wall.