RO Water or Deionized Water?

[paul_wash]

So which is better RO water or Deionized water?

I have been using deionized water for years. Everything is pretty healthy. I have noticed trends in my city tap water between summer and winter. Right now, it seems the city water people have increased PO4 since the outside temperature has warmed up above 75F.

And wouldn't you know it, boom, I have had an increase of dinos and hair algae clumps -- yes hair algae clumps -- the tank is 1.75 years old -- seems like I shouldn't be bothered with this.

I do kalk and have ceased additives for about 3 weeks. My numbers look good. I fanatically recharge my deionizer resins and never run anything through exhausted resins.

Now checking my deionized water directly for PO4, I barely have .03 ppm if that. But I do realize that our PO4 test kits are kind of weak. I exhaust my resins within 60 gallons of water making. The blue anion resins goes faster than the green cation resin. Which leads me to believe that my water is pretty bad if it exhausts the resins so quickly.

I have heard seen several different figures on the purity of deionized water (about 95% pure is the average thought). I have heard several thoughts that deionizer units should be used after an RO unit.

So whats the thought here? RO or Deionized water? Should I add an RO unit to my setup? Could this explain the not quite right water conditions for the past 2 years? Have I been looking at everything else except the source?

 

[NMreefer]

You're correct. It should be RO then on to a DI cartridge. You should be able to test that water and not see a phosphate reading. Maybe very very small. You DI cartridge will also last alot longer. This also depends on the RO unit you're using.

Phillip

 

[Anonymous]

I have heard seen several different figures on the purity of deionized water (about 95% pure is the average thought). I have heard several thoughts that deionizer units should be used after an RO unit.

I don't know who give you the figures, but a properly working DI unit will remove almost all ionic chemical in the water and make it a decent insulator. In fact, that's why they can use DI water for washing powerline and other dangerous areas with proper equipement. Tap water is at least 99% pure, with less than 1 % toxin and nasty chemical, so DI must be much more purer than 99%.

 

[paul_wash]

One source: http://spectrapure.com/faq_p0.htm#howdi

In this link, spectrapure is actually referring to a purity of 95% for organics and ionics of 99.9% purity. Of course, they are saying that the RO/DI system does this and not the DI alone. The groupies at the LFS say about the same with DI systems being the poorer of the two. However, the LFS (the guys who actually run it) says there is no difference. Of course, they use a RO/DI system.

One would definitely think if tap water is 99% pure that the water through a DI unit would be even more pure (> 99%). As far as purity - is this just the nasty toxins or does this include the heavy metals, etc?

Seems like the unit is running correctly -- I mean aside from ensuring the resins are charged and the carbon block is in good shape and the water is made at a fairly slow rate...what else can I do? BTW: Its a Kent DeionR.

Ok, so its looks like 1 for RO/DI -- David do you think it is a waste of energy and money for RO + DI? Or am I just chasing down another ghost that still isn't going to give me the results I am looking for?

The results being the elimination of the food source for the persistent dinos and resurrected hair algae -- keeping in mind this nearly the last thing I can do since I think I have eliminated all other obvious sources...

 

[LFS42]

personaly, I prefer DI
I can get it faster than RO anyday.
and with 5 tanks and other service accounts, I can't wait for RO.