Ro/di /

OK was looking into maybe getting a ro/di unit from bulk reef whats the difference between the ro unit and the ro/di unit and which one do I need for my tank. Also if now you are putting perfect water in your tank do you need to add trace elements other than the reef crystals I am using now the dosing of mag-cal. Thanks in advance.

 

Difference with the RO/DI versus plain RO is huge.

If you are going to go for a filter - do not waste your money on a RO only filter. You will still have an elevated level of TDS (Probably between 2-10 PPM TDS) - the DI portion of the RO/DI filter takes these last TDS out of the water - polishing it to a near 0 TDS (there will likely be a small fractional percentage of a single TDS even in good RO/DI water - but its so slight its not picked up by most of our TDS meters.

If you are using RO/DI and reef crystals along with a good dosing regimen of Calc/Mag/Alk - then there should be no need to add trace elements if you are on top of your water changes (weekly - about 10%).

 

Also my ro has 0 TDS before the di also is it bad to let the membrane run fir short periods if I bypas the di first. What I am wondering is TDS creep bad for the membrane?


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What does RO/DI do to the ph of your water?

 

That's a good one for AZ Desert Rat

But I can say this:

If you are concerned about he pH of the water in using it for weekly water changes of about 10% - by the time you mix your saltwater in an bring it up to temp - your pH will be plenty high - I am sure over 8. The 0 TDS water should have a basically neutral pH since there are no extra/less hydrogen ions to give it a different concentration.

For Topoff water - you should only be adding a small ammount at a time and as such the lower pH of the RO/DI water should not affect the pH of your DT due to the DT's buffering capacity.

 

You should get 10 gallons of water from the unit each use to keep TDS creep away. So I would say it most likely does not do the membrane any good.

 

I'm actually buying a RO/DI unit for BRS today, definitely go with the RO/DI as others have said as it will clean the last little bit of contaminants out of the water.

However I do have a question leading off of shoebox's. What is the difference between the economy RO/DI and one that might have a few more stages? If one were to add the duel TDS meter to know when to replace filters and such and they both produce 0 TDS then why would I need more stages, thus spending more money on more filters?

 

So what you are saying is that every time you use the RO/DI unit you should make 10 gallons of water.

 

Ya that's what I thought dose any one know where to get the most info on how ro care for a unit. Also what is TDS creep and how dose it affect the membrane.


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IMHO - AZDesertRat is THE authority on RO/DI filters on this forum.

PM him or wait for him to drop on by . . . .