Why RO\DI?

Not sure. This is a good company for RODI units.

SpectraPure Water Purification Products

You could also go to our sponsor, Bulk Reef Supply

http://www.bulkreefsupply.com/store/products/reverse-osmosis-filters-and-systems

 

You can buy the water itself at a LFS (not PetCo, but a mom and pop type shop). I would recommended against this, as most don't ever check their units and maintain them properly, which defeats the point of having an RODI.

As Seano said, you can buy online from quite a few places. Spectrapure is the best, by far, though, so I would recommend them. Just wait for AZDR's post on why lol.

 

RO/DI is more pure than distilled.
The reason we use it is consistency, when you have you own RO/DI you have ultimate control of your water quality and you get the same pure water every time as long as you keep up with the minimal maintenance required.
A good salt mix has all the elements you will need in the correct amount when you mix it with RO/DI so you maintain balance.

Yes DI is necessary, the RO acts as prefiltration and gets 90 to 98% of the contaminants but its the DI that does the final polishing. There are things each is not particularly good at removing by themseles so it takes both.

Spectrapure is also a Sponsor or this site and would easily be my first choice, none of the others compare and best of all their units are on sale for $100 off retail right now.
http://www.spectrapure.com/email/customer-appreciation.html

 

Awesome deals....

I have a spectrapure... I love it.

 

RO only 90-98% of contaminants out??? How is this possible when you get maybe 1-2ppm when measured???

DI is important for trace elements to be fully effective. The amount of ions left in water effect the potential effect desired. SO the DI takes all the ions out thus making dosing more effective.

 

If you are getting 1-2 TDS with RO onoy you have very low TDS to begin with. Its also important to note some things do not measure well with a hobbyist grade TDS meter so may be present without you knowing it. Some weakly ionized substances include phosphates, silicates and nitrates, none of which RO is particularly good at removing so you need the DI.

 

Hanna instruments meter.

I have installed more then a hundred RO systems and usually get these types of reading even on wells in gold county.

BTW, I do have a spectrapure DI for my reef.

 

Is it a hobyist grade TDS meter or a resistivity/conductivity meter? TDS meters are not sensitive enough on the low end. If anything try using a HM Digital COM-100 which is 10x more sensitive and even has a conductivity mode.

If the TDS was 1-2 what was the tap or raw water TDS? I have been doing this for 35+ years and find your claims a little suspect. A membrane is a 90-98% device in its stock form regardless of the manufacturer. My tap water TDS averages over 800 most days and with a normal off the shelf 75 GPD Dow Filmtec I get between 15 and 16 TDS with RO only, thats based on 4 different systems and membranes. When I switched to the Spectrapure MaxCap that same 800+ TDS dropped to between 5 and 6 TDS doing absolutely nothing else. When I had the Typhoon III RO/DI it took that 15-16 down to 0 TDS but DI only lasted 150 gallons per 20 oz DI cartridge or refill. With the MaxCap my very first DI lasted 830 gallons and ever since then it been over 1000 gallons per DI cartridge consistently, big difference in long term operating costs.

 

It is a calibrated Hanna Pen meter...so close readings I expect. Pre filter is anywhere from 20-50 on city treated water and up to 600 on well water with occasional spikes. I am a displaying dealer of this product:

Everpure Water You Can Trust

I use the spectra pure for the DI aspect in my own reef.

Anything above 5ppm is not acceptable IMO.

 

Wow. Expensive.

Watts Premier is about a mile from my house and sells similar units for about a third of that or less. They have been very helpful in the past too by bench testing membranes for me in their lab.