Switching to RO/DI

[Hamsnacks]

Have a 300 Gallon in total tank.
Currently Its filled with tap water but the RODI finally arrived.

Initially I thought to just produce 300 Gallons of new RODI water and completely empty the tank, but then I'd run into a few issues:

1) Where to store 300 Gallons?
2) Draining the tank and stressing out the fish
3) Would need to purchase more salt roughly cost a little over $100CAD

So then I decided my best and most convenient option would be leave everything as is and just do top offs with the new water.
Which would be about 30-35 Gallons every week.
And then also remove 50 Gallons a week.
Do that for about 2 months.

Would that be fine?

Also a side question, how long does salt typically stay in water. So in theory if you're only using RODI water and doing top offs would you not need to add salt for a few months?

Thank you

 

[naterealbig]

So then I decided my best and most convenient option would be leave everything as is and just do top offs with the new water.
Which would be about 30-35 Gallons every week.
And then also remove 50 Gallons a week.
Do that for about 2 months.

Would that be fine?

Yes, assuming when you say "remove", you are talking about a water change.

Also a side question, how long does salt typically stay in water. So in theory if you're only using RODI water and doing top offs would you not need to add salt for a few months?

Thank you

Theoretically the salt will remain in the water indefinitely. In real life you will get some small loss in salt, due to splashing, and salt creep (as you can see below).

 

[AdamB]

Yes . just do the 30-35 gallon water change during your regular change intervals . I don’t know what your growing in tank but I don’t think it’s necessary to do that large a change every week unless your corals are in bad shape and have a huge algae problem .
Salt pretty much stays in tank just as stated above in thread. All you have to Sonia top off with rodi water to replace water evaporation .

 

[naterealbig]

Yes . just do the 30-35 gallon water change during your regular change intervals . I don’t know what your growing in tank but I don’t think it’s necessary to do that large a change every week unless your corals are in bad shape and have a huge algae problem .
Salt pretty much stays in tank just as stated above in thread. All you have to Sonia top off with rodi water to replace water evaporation .

I thought the same thing at first, but 30 gallons is only a 10% water change, which is pretty typical (and maybe even a little small) for a new system..

 

[AdamB]

Yes . True . Forgot it’s a 300 gallon system . If your parameters have been okay you do either .

 

[lapin]

Have a 300 Gallon in total tank.......

So then I decided my best and most convenient option would be leave everything as is and just do top offs with the new water.
Which would be about 30-35 Gallons every week.
And then also remove 50 Gallons a week.
Do that for about 2 months.

Would that be fine?

A 50 gallon water change will be about 16%
You could do that for 2 months then switch to 10% a week to save on salt.

 

[mike550]

@Hamsnacks this is all great advice. I’d go with your plan of 10-15% water changes on whatever frequency you are doing now. If you’ve been successful with tap water so far then I don’t see a huge urgency to make a drastic water change.

As far as salt replacement I just installed a RODI top off system and watch salinity carefully but so far so good. That said, I also change around 15% water change every couple of weeks so that probably helps rebalance salinity.