opinions on ro vrs. ro/di

[duperdave]

looking for opinions or facts. On this matter.

[Mark9]

I believe the general consensus is to use RO/DI.

[thegrun]

A RO filter will remove around 90% of the impurities in your water. The remaining 10% may not be a problem for you or it could be a disaster or a slow ticking time bomb as things like heavy metals build up over time. The only way to know for sure would be to have a sophisticated (and expensive) analysis of your water done. Even that would be subject to change as may cities and wells experience rather dramatic seasonal changes to their water supply. A DI filter will remove nearly all the remaining contaminates from your water. The bottom line is that for most of us the few extra dollars it takes to run a DI filter after the RO filter is a wise investment considering the amount of money we have tied up in fish and corals.

[ca1ore]

I ran a RO system only for years. TDS on the output was about 10. Started getting 'old tank' syndrome, and while I cannot be certain, I suspect long-term build up of TDS was at least partly to blame. I now use a DI cartridge on the output and my TDS is zero.

So, you decide!

[HumbleFish]

A RO filter will remove around 90% of the impurities in your water. The remaining 10% may not be a problem for you or it could be a disaster or a slow ticking time bomb as things like heavy metals build up over time. The only way to know for sure would be to have a sophisticated (and expensive) analysis of your water done. Even that would be subject to change as may cities and wells experience rather dramatic seasonal changes to their water supply. A DI filter will remove nearly all the remaining contaminates from your water. The bottom line is that for most of us the few extra dollars it takes to run a DI filter after the RO filter is a wise investment considering the amount of money we have tied up in fish and corals.

+1 Zero is what you are shooting for, so you can control what goes into the tank via your salt mix.

DI water should have a TDS reading of 0; RO will never have a 0 reading.

[Kyuss]

+1 Zero is what you are shooting for, so you can control what goes into the tank via your salt mix.

DI water should have a TDS reading of 0; RO will never have a 0 reading.

Unless my inline TDS meter is inaccurate, I've seen 0 tds coming out of my RO unit. It normally sits at 1, but a few times on extended fill-ups I've seen it go down to 0 and stay there.

That said, I'd still go with a DI cartridge on any RO system for an aquarium setup. The bulk of the price is in the main pre-filters & RO system, so I don't see any reason to skimp out the last little bit. The whole point of the system is to get 0 tds water, and even having personally seen 0 tds out of my RO setup, it's definitely not the norm or guaranteed. On the plus side, my DI resin lasts a long time since the water going into it is so low, which means operating costs are only slightly more than just RO water, yet I'm still sure to get 0 tds all the time.

[Salty Dog24]

RO/DI water gives you the most consistency in your tank. Your using the highest grade/quality of water every time. RO only water still has TDS in it, RO/DI does not. Your livestock is expensive, why not provide it with the best quality of water that it needs to thrive in the healthiest environment you can provide? The largest ingredient we have in our tanks is Water. Therefore, it should be of the highest quality. RO water is generally 3 stages. 1. prefilter 2. carbon block 3. RO membrane. RO/DI water just adds a fourth DI stage to the purification process. The Most Important Stage.

If you have been using Tap water or RO only water your rocks and substrate are saturated with the contaminants left in the water. You will never completely undo the effects of using Tap or RO only, or remove 100% of the pollution it added to your tank. All you can do now is dilute the contamination left from RO only water, or Tap water, with perfect RO/DI water

If you use the best water, then your worries, losses of live stock, algae blooms will be less, than using Tap, and RO only water, provided you practice good husbandry.

[dkh0331]

RO/DI since 1994.


hth

[MARINECRITTERS]

RODI is better then RO, because of the DI...

[HumbleFish]

Unless my inline TDS meter is inaccurate, I've seen 0 tds coming out of my RO unit. It normally sits at 1, but a few times on extended fill-ups I've seen it go down to 0 and stay there.

You must have amazingly good tap water. Ever test the TDS of that?