I would spend a bit more on the Vertex RO/DI unit. It is 100GPD and has a built in booster pump and inline TDS meter. It is electronically controlled and automatically back flushes to clean the filter etc. every 15 minutes. It only produces about 1 to 1.5 gallons of waste for each gallon of RO so it is very efficient. And the price is good if you consider the price of adding a TDS meter, back flush kit and booster pump to a cheaper unit. I am fairly certain this is very similar to the unit I saw at a commercial water purification store where their only added step afterward was to UV sterilize the water after RO/DI.

I'm not sure where Chilliwack gets their water from.. but here in Coquitlam (about 1 hour away from Chilliwack) I get 12ppm on ym TDS meter right from the tap. I just use a DI unit. Works for me and many other local reefers.

This is true but often very difficult and impractical to implement. Measuring your tap water TDS is as simple as measuring your tank salinity. All you need is a very inexpensive TDS meter. Better safe than sorry is not an excuse for wasting valuable resources.

As soon as i find a tds reader ill post my reading and then mabe i can get a better idea of what i need to buy. Thanks for the opinions so far :O) so many options makes this all confusing sometimes,
I can say to a earlier post i really dont think im over feading. I take the frozen food, a tiny bit, put salt water in it to defreeze it, dump out the water and use a tooth pick to pick the food out and put in the water. The fish pritty much eat it almost before it hits the water, and i watch to see if any sink and it never does. Then i turn on the pumps. I do use a medicine dropper 2 times a week to squirt the brittle star so i guess that might be contamanating the water a little, but i use so little i thought he must be munching it all up right away?

Here is something interesting but also something that I suspected.

Chilliwack gets its water from an aquifer (ground water). It is much more susceptible to contamination (from what I have heard.. I am not an expert).

Have you checked your source for nitrate or phosphates? (right out of the tap)

You can find more info RE: your water here:

http://www.gov.chilliwack.bc.ca/main/page.cfm?id=1249

I forgot to say.. I have a Lawnmower Blenny that keeps my green algaes in check.

Soooo I made it out to JL aquatics, already cant wait to go back. I bought a tds meter when i was their, and it says my tap water is 065 ppm. Thats pritty good isnt it? And if so should i just buy a R/O Or should i still just buck up and buy a RO/DI?

65ppm isn't bad.. I get 14ppm out of my tap.

I guess if you're really concerned then you may as well get the full RO/DI until.. I think J&L has one for $200 or so.

You could just get the Aquarium Pharma DI filter for about $60. It really depends on the size of your tank. With about 65ppm the filter will last you a while if your tank isn't big. And if you're patient.

This works nicely if your lucky enough to live in an area where your PPM is reasonably low:

http://www.jlaquatics.com/product/ro...er+Filter.html

Obviously there are seasonal variations in tapwater TDS but lately I've been contemplating just removing my RO membrane from my RO/DI unit. Our TDS is around 20 ppm on average at worst here in Victoria. I'm considering going with a 5 micron then 1 micron prefilter and two consecutive carbon blocks then my DI. This way I won't have the rejection water and I doubt I'll have any problems with exhausting my DI too quickly.

Sorry SP, have to go with Brad on this one. For such an expensive hobby its just not worth the risk to introduce phosphates, Chlorine or any dissolved solids. You don't buy a brand new BMW sports car and then fill it with regular gas so why would you put unpurified water into a reef system? Besides, it doesn't "destroy" or make the waste water unusable so there are many applications for RO waste.
Levi