Fan reducers to increase air flow?

Just set up a new tent, and what with running HPS now (LED previous) I've come into high temps (35 Celsius) so wondered:

Would running a 6" cool tube, which then reduced to a 5" to my 5 inch extraction fan aid my fan? I imagine it would maybe lighten the load on my fan or funnel more air through it. Or do nothing.

Is this common or a dumb thing to do?

Thanks

Reducing outlet size or duct size to a size smaller than the fan outlet will wear your fan out unless its a squirell cage fan,I run 3 600 watt hps hoods per table with all lights vents hooked up in a Daisy chain from one light to the next,a single 8" vortex isn't enough to cool my lights so I use 2 fans per 3 light run,one fan pushing cool air into the light chain with the 2nd fan at the end of the run pulling hot air out.

If a single fan isn't cooling the glass where its cool to the touch adding a 2nd fan will fix your heat issues every time, one pushing & one pulling your cool tube should be cool enough for the canopy to touch the glass without any burn ,reducing ducts also restricts air flow & is best to avoid .

As said above, reducing ducting size will put more stress on your fan motor and wear it out quicker.

Doo-flop said:

As said above, reducing ducting size will put more stress on your fan motor and wear it out quicker.

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as well as reducing air flow.

you could use 8''-6''reducers at the cool tube, which will allow more air flow and let the fan run with less restriction. this could help lower temps. what size is the light, and what size is the fan, and what size is the carbon filter (if you are using one). please include brand names in case one of us wants to look up the actual part/s.

I think I maybe didn't describe accurately what I was trying to say.
Basically the tent isn't running a cool tube as yet, however I wondered whether I could run one with a reducer to increase the air flow due to the longer system. The system would be
Carbon filter > 6" hose > 6" cool tube > 6 to 5" reducer > 5" hose > 5" fan > 5" extracted to atmosphere.
As it stands it's merely carbon filter > 5" fan > 5" extracted to atmosphere.

Black orchid 1 metre x 1 metre x 2 metre tent with velvis 5 inch fan and 600w HPS with reflector.
Not sure which cooltube to get yet. But my temps are high and I'm in the UK in winter with all the windows open and my place is still toasty and warm..

If you can find the performance curve for your fan and filter, length of runs, material used for piping re ridged or flex, and any elbows, I can tell you what your CFM's and FPM will be approximately, but as a rule reducing will. as stated, reduce effeincies, cause noise, and yes, if really bad cause the motor to burn out. Also you will need to make sure the air is not going through filter to fast, there will be a rating.