distilled water

[esato]

Is distilled water from your local grocery store ok to put in your salt water tank for the water that has evaporated?

[wds21921]

Distilled water generally turns acidic when introduced to Carbon Dioxide that is present in the air. It's pH can get as low as 5.8, not ideal conditions to start with IMO.

Filtered water by Culligan or one of the other water filtration companies is much better and more stable. The best though is RO/DI.
I think most water companies who install the water purification machines in stores are at the very least RO in nature so it's a great start compared to tap water.

[divecj5]

I agree that RO/DI would be the best way to go but that said, water from filtered machines will at least have a RO membrane used for filtering so it's WAY better than just treated tap water. I was thinking of just using treated tap water for my initial fill of my 55 but after some thinking, I went with an RO/DI unit and just figured it would be better than dealing with the algae problems.

A lot also depends on the TDS in you tap water as well. Some places water is a lot better than others.

[DgenR8]

Here's the deal......
IF you want to trust "machine water" for changes/top offs get yourself a TDS meter so you can at least monitor the quality of the water you're buying. Some of those machines don't see nearly as much service as they should, and you might just find that your tap is far superior to what a machine is charging you for.
Take into consideration the cost of store bought water, your time and gas money to pick it up, and the wear and tear on your back. Unless you have a very small tank, you're likely to find that the cost of a new RO/DI unit of your own will quickly become savings over the store bought. When you add the possibility of diminished quality from a machine, it's almost a no brainer.

[wds21921]

As DgenR8 stated the convenience factor alone is enough to at least "highly" consider it.
Also the fact that "you" will have control over the filtration and not have to rely on some service guys accuracy is a much better insurance IMO.

I too would consider a TDS meter before anything though. That will at least let you not only know what your working with but will serve as an indicator later should you decide to purchase your own RO/DI system.

[philagothos]

You should probably consider getting a TDS meter even if you are setting up your own RO/DI. It's the only way to know when you need to change your RO membrane. I bought a portable TDS meter because I have a small tank and my RO/DI needs a new membrane as well as new resin so I am using store bought RO water. The water I have gotten there has varied from 2-6 TDS, whereas my RO/DI was constantly putting out ~6 TDS. Also, be aware that the each time you turn on your own RO/DI you need to run a gallon or two out of it before you use it. I had a buddy make some water for me from his RO/DI, but he forgot to waste the first gallon. As a result the water ended up with a TDS of 14, worse than even the store's RO machine.

[wds21921]

???Once the membrane has been rinsed of any shipping material (and remains wet) you should get a constant low number shouldn't you? My first gallon out of the RO/DI is the same as my last.

[DgenR8]

First gallon or 2 when you replace any of your filters should get tossed.

I've seen the recommendation to toss the first couple pints on each start up, too. My RO/DI is my auto top off. It starts and stops a couple times a day, and I don't toss the "beginning" water any of those multiple times.

[suju82]

Ok I was just tested my tap water by it self and after mixed with salt over a day later and my ph is good, nitrate/nitrite are 0, ammonia is about .3ish. Should I really invest in an RO system or save the money for something else? (My ammonia in the tank is 0), nitrite is 0, nitrate is 25ish so working or bringing that down)

[AZDesertRat]

You need a TDS meter to test your tap water. Aquarium test kits are not going to tell you everything you need.
As for RO always being the same, RO membranes experience what is called "TDS creep". This means the firts gallon or so each time you start it will be higher in TDS for a short time. This is true of all membranes. The ways to get around this are either waste the firts little bit which isn't always practical, make larger batches so the little bit of start up TDS is diluted in a larger volume of RO or the best solution is to follow up RO with DI. A good DI system will deliver very low to 0 TDS even if incoming water has measureable TDS in it.
Water is the single largest component in a reef tank and you want the very best every time you add it without question. A quality RO/DI is probably the most important investment you can possibly make. Don't skimp on a unit by trying to go the e-bay route or you will be doing yourself and your tank a disservice.

[suju82]

What about the coralife ro unit by big al's http://www.bigalsonline.ca/BigAlsCA/ctl3664/cp18144/si1315140/cl0/coralifepurefloiiro24gpd2canister

[AZDesertRat]

Way way overpriced.

www.spectrapure.com , www.thefilterguys.biz , www.purelyh2o.com , www.airwaterice.com and www.buckeyefieldsupply.com are all very good units. All have good RO/DI units in the $130 to $200 price range with the very best they have less than $275. Several of them supply units with TDS meters and pressure gauges. Look for one with a refillable vertical DI filter and a 75 GPD RO membrane.

[suju82]

So I should get not just a R/O system but an R/O system with DI right?

[DgenR8]

<a href=showthread.php?s=&postid=7972308#post7972308 target=_blank>Originally posted</a> by suju82
So I should get not just a R/O system but an R/O system with DI right?


That's correct.