Which UV to Use

[Thor2j]

I'm in the middle of a switching from a 120gallon to a 240gallon total water volume tank. I have a 40w UV on my 120. I purchased a 80w aqua ultraviolet to put on new system. I've heard for many years you really want 3 to1 to really be effective. My issue is the recommended flow on the 80 is 2452 on the low side. I'm planning on around 800 gph. I'm going to have more exposure time, but is this necessarily a good thing?? Would you put the 80 or the 40 on new system?? Thanks
Ultraviolets website recommends a 15 watt for 240 gallons for marine systems so you don't kill beneficial bacteria.

 

[vetteguy53081]

You want at least 25 watts, preferably 40

 

[Thor2j]

You want at least 25 watts, preferably 40

Well I have a 40 and an 80

 

[Sean Clark]

The 40w you have should be perfect.

 

[vetteguy53081]

Well I have a 40 and an 80

40 is your guy

 

[Thor2j]

40 is your guy

So you disagree with the statement of 3g per watt??

 

[vetteguy53081]

So you disagree with the statement of 3g per watt??

Not so much disagreeing but if water passes through at a slow rate , you can go higher. I run UV at night allowing zooanthellae and algaes to form during the day - essential to coral health