water changes procedure

[reefr]

Hi everyone I'm new to the reef hobby ,I have a 90G AGA RR tank it's running for about 3 months now, just had a question about what's everyone water changes procedure ,please let me know if this a correct way of doing it.
I prepare the RODI water a week before making sure salinity and temperature are the same as the tank and then I use 2 pumps with a gate valve at the end of each hose to adjust the flow one goes from my new water container to my return in the sump and the other from the incoming section in the sump to a drain and it's done simultaneosly and slowly .
My question is :Is it ok to do it this way or shoud I drain the old water first and then add the new water?
Thanks for your input.

[wasabi]

it would be better to drain the old water first. you will always do less of a water change using that method, because you are draining a portion of you newly made salt

[Casey]

Welcome To TRT Reefer!

I do one tank that way and my other tank I drain it first whatever is easiest for you will work but it is probably best to drain first.

[reefr]

Thanks guys , and thanks for the welcoming Casey, I found lots of good info here.
By draining first you guys use the sump or directly from the tank?I would need to shut off the return pump?
Thanks

[grazhopr]

Hi reefr, and welcome to TRT.

I would suggest you drain the old water first. You can always drain your sump to a safe level where the return pump is not going to run dry.
If you need to make a massive water change and the sump needs to be emptied, plus a portion of your main display, shutting your return pump off for a few minutes should not be a problem. You can dump your new water into the system as quick as you can and start you return back on.