Pure Water

[Vindicator]

Ok, so I am trying to learn all I can on SW tanks before I take the plunge. I have lived right next to the Florida Keys my whole life, and have always loved the reefs.

Anyway, this question concerns water for the tank. I see that pretty much everyone uses a RO/DI unit to filter out there tap water. But I cannot find to much info on what needs to be done to maintain a RO/DI unit - is there parts that need replacing? filters to change? and how often?

ALSO, using something like a Pure water filter on the faucet will not be good enough? like some you see advertised for home drinking water.

[tkos]

I assume that the cost per volumn of those pure faucets would be quite high compared to a RO unit.

[melosu58]

Replacement of filters, DI cartridge and RO membrane all depend on use. I only have a 35 gallon per day RO/DI unit and I change my filters every 6 months and my DI resin every yr and RO membrane every 2-3 yrs. A TDS meter will help determine how often a RO membrane needs to be changed.

[Kurt_Nelson]

The "water filters" or PUR filters on the faucets do a decent job for drinking, but it doesn't produce "pure" water. My tap water runs about 88 ppm TDS. (TDS is "total dissolved solids" and is a measure of purity. Pure water will measure 0 ppm.) After I run my tap water through a Brita water filter, the TDS is around 40 ppm. Not even close to pure.

[Vindicator]

Ok, that is not bad at all, I was really worried I was going to be running out every few weeks to replace everything. But if your getting at least 6 months out of it, then that is not bad at all.

OH! also, did you bother buying the pump attachment? or do you think regular pressure is enough?

[melosu58]

For me regular pressure was enough

[Ziggy953]

You need at least 45+ psi to make the RO/DI unit work properly. Unless you are on a well you will probably have that much or more in water pressure. Also checking the TDS of your water right out of the tap is a good measure of what kind of life you will get out of your filters. I have a 100gpd unit and I change my filters once a year. I have very good water where I am so that extends the life of my filters. I haven't changed the RO membrane as yet and I have had the unit 2.5 years. I still get a 0TDS coming out of my unit.

As a side note getting an RO/DI unit to start out with will save you a lot of headache down the road. The water you start with is the foundation that your tank will be built on so you want to start out with the best possible water.

[CluelessInNY]

Is there a reason that simple bottled water can't work in a tank?

[Ziggy953]

Most of the time bottled water came right out of a tap somewhere and is not pure water.

Look here is the deal. If you are going to invest $1000s in an aquarium with delicate corals and fish why in the world would you negelect the biggest part of the whole system? Less then $150 for the most part will ensure that you have perfect water to start out with. To me it is a no-brainer. Check on ebay they sell for a lot less then that too. I got mine for $69.99 and $30 shipping online. By the time you spend the money buying water you could have picked up several RO/DI units and started your own water purification plant.

[cmor1701d]

I have to agree with Ziggy here. I have a 100 gpd unit. My tap water tests at 185 -215 ppm. I have clear cartridge housings on mine so I can see when the sediment filter gets dirty. I replace the sediment filter (10 micron) about 4 times a year. The two charcoal filters (5 and 1 micron) once year and DI when needed. Although my DI resin is color changing I don't replace it till the tds meter starts showing some tds after the unit.

[fijiwigi]

I fought buying a RO/DI unit for some time once I did I kicked myself for not doing it earlier great investment I got my 100 gpd unit from Melevsreef. for 199.99 shipped it produces water fairly fast probably more than 100gallons in a day. I fill a 32g trash can in about 6-7hours. I still have not purchased a TDS meter yet since my unit is only about 3months old. Also to add to the thread on a related topic

I want to know of a good place to order a decent TDS meter for cheap or if I can just go and buy one locally.

[Kurt_Nelson]

Originally Posted by CluelessInNY

Is there a reason that simple bottled water can't work in a tank?

It depends on what you mean by "bottled water."

If you mean distilled water from a store, then that's probably just as good as RO/DI - but you don't really know. It all depends on the machine/facility that is making the water, which you have absolutely no control over.

If you mean bottled water for drinking, then no... I wouldn't recommend it. Granted, it does have the chlorine removed, but to make it taste good, they normally add various minerals and salts back into it. It's probably consistant between brands (same recipe all the time), but not "pure."

[roka64]

Kurt is right, they put stuff in the drinking bottled water to give it taste (what ever that means, I used to drink out of garden hoses and am still alive today), try different brands of water. Deer Park tasted nasty for "pure water" when I tried it years ago.
RO/DI is the best way to go IMO.

[Ziggy953]

Marinedepot has a few different TDS meters on their site. I think Melev has an inline TDS meter that he sells that gives you before and after readings. I can't remember.

[cmor1701d]

You can also fnd a tds meter on eBay for around $20.00