Largest safe water change

I have my Spectrapure RO/DI on the way. As of now my 90 has all tap water in it, but the parameters are excellent(for tap)
I'm wondering what the largest safe water change I can do would be, with the new RO water?
Can I do a 50% and then another 50% a week later?
Or can I do a higher percent?

I have a yellow tank, 2 clowns, and 6 line. Also, 1 pep shrimp.

 

I do 20% weekly. So I would think that 50% would be your highest safe point.

 

If your params are all good there is no need to do such a massive water change. It's good you are going with R/O DI water now. Just do weekly 10% changes. It everything in your tank is healthy you should not risk doing a huge water change all at once.

 

whatever damage the tap water is gonna cause has already happened, just do weekly 20% changes for the next 6 weeks.

 

120% ?

 

Thanks guys. Makes sense.
I'll just do 20-25 % over the next few weeks.

 

Sure, any problem with that?

 

No. Not really.

 

I totally agree with Telgar's 20% over the next 6 weeks (or 8 weeks or 10 weeks.)
It's the safest way to completely change out your water. Then start either a 10% weekly or 20% bi weekly schedule.

 

heh its not actually 120% of his water volume being changed out...

but yeah id go with everyone elses recommendations as well. do 10-20% water changes weekly and eventually you'll have converted over to RO 100%. as telgar said, whatever 'damage' was done by tap water is already done. now that you're on RO you know you have 0 TDS (hopefully) and 0/ppm across the board (hopefully). you wont be introducing more phosphates, etc with your RO. so you should notice over time that your water chemistry in the tank is easier to maintain with the RO water.