Is my calculation correct?

[MadReefer]

Considering my Dino issues. I am taking steps to rectify and am now considering an RO/DI unit.
I have a 72g DT and 2og sump. Sump is 1/2 full so let's say 10g; total water volume 82g rounded to 80g.
My question is how long would it take to switch over to RO/DI only using my ATO?
The reservoir holds 4g water and needs filling every 5 days. On a 30 day calendar that would be about 16g a month. so 80g / 16g would yield 5 months to completely switch over.

Is this correct or am I way off base.

 

[DangerDave]

My RODI is an inexpensive unit, it is rated for 50 gallons a day. With my booster pump to make up for my lower PSI, I'm getting much more than that.

Dave

 

[myrjon]

Mark I believe it would take a while. With that scenario. Just do water changes. Ato would be very slow...