How much top-off for a 240 gallon?

[reeftank21]

How much should I expect to add to my 8'x2' 240 gallon. I'm trying to plan a top-off resevoir.

thanks

 

[waldomas]

I have a 180 with a 2 x 4 footprint and I top off 30 gal / wk.

I do use fans on my sump and tank. I also have almost 1200 watts of lights.

 

[waldomas]

Ooops...I meant a 2 x 6 footprint!

 

[siropa]

I used to have a 240 that I usually ran a fan for cooling on the sump. I lost 7gal/day with it.

 

[Red Sea Purple Tang]

I use a 10g tank that remains 3/4 full at all times with a float switch to the RODI. It's the tank on the top over on the left. I would estimate 2-4g per day.