[Samper]

Which is better for our purposes?

The reason I ask is that I just found out today that I have access to a very nice Still. It's a Thermo Scientific Barnstead Extra-Duty Still...sounds crazy. Barnstead A1015-C Classic Still - Phoenix Equipment, Inc.

Just to test it out today I made 30 gallons of water. This tested 0 for tds obviously...but I did this in 17 minutes.

I also have access to a very large RO/DI that I'm told can produce 30 gallons in about 30 minutes. I don't know what kind it is yet though.

Leebca in this thread How to Make a Successful Water Change says...

"it is important to replace evaporated water with distilled water (if you have a small aquarium), or RO/DI or deionized water for larger systems. Maintain a constant specific gravity of the marine system, a constant pH in the proper zone, and a constant temperature."

Why does system size matter?

Then I read this

"distilled water comes the closest to the definition of pure drinking water. The process of distillation removes the broadest range of contaminants over any other point of use (POU) system. "

BLOWING THE LID OFF DISTILLED WATER MYTHS

SInce I have unlimited access to both which is better and which should I be using?

[Samper]

I'm going to learn more about this still before I use water from it.

The “How To” Guide to Reef Aquarium Chemistry for Beginners Part 1: The Salt Water Itself by Randy Holmes-Farley - Reefkeeping.com

"The best distilled water is perfect for our applications. Typical commercial distilled water is likely acceptable, as long as it has not been exposed to metals such as copper in condensers, pipes or holding tanks. Unfortunately, it is not easy to know the production history of distilled water, and testing with most copper test kits may be inadequate because they may not accurately read low enough to detect its presence"

I am not registering copper with my kit and it didn't come from a holding tank so I think it will be ok but the condenser part I am unsure of. Does anyone have any thoughts??

[wozza]

ide phone up the manifature of who ever makes the distiler your using, im guesing thats your best bet.

james

[Ninong]

Why does system size matter?

Because if you have a small tank (like maybe 20-30 gallons), the cost of distilled water for evaporation replacement wouldn't be all that much. If you have a larger tank (say 75 gallons and up), it might pay to buy an R.O./D.I. unit.

[Ninong]

Distilled water and R.O./D.I. water are identical if they're both perfectly produced. Chances are the distilled water will be more perfect than the R.O./D.I. water. The only thing you have to be certain of with distilled water is that the water never, ever came into contact with copper, brass, bronze, etc.

[Samper]

Thank you very much!

[leebca]

Samper,

Most still manufacturers can and will provide an analysis of the water their product makes. That may be worth asking for.

Although most, not all stills are glass lined, preventing the condensed water from coming into contact with any metallic materials used to make the still. There are stills that are made without such protection and the 'pure' distilled water comes in contact with metals. Thus the cautions about making sure the water is made without metal contamination.

Deionized water is just that -- water where ions have been removed. Most deionization is performed by resins. What the resin does is replace the absorbed ion with another component or compound. There are two basic resin types -- one replaces positive ions the other replaces negative ions. If both are used the water is very much reduced in ion content except for the ion that was used to replace the removed ion. Obviously the whole scheme is based upon the ionic charge of the molecule. There are several molecules with little or no charge (when the molecule is taken as a whole) which are not affected by ion exchange systems. That is some such contaminants can pass through the resins and not be removed from the water.

Reverse osmosis is based upon a membrane used to 'filter' the water. The membrane is so fine (tiny pores) that only very small molecules will pass through the membrane. The membrane will hold back very large salt molecules, but its big claim to fame is holding back large organic compounds. The membrane allows only molecules about the size of water or smaller to pass through.

Between the three treatments (dual resins and one RO) very pure water can be produced.

Distilled water is of course boiled - evaporated water whose steam is cooled (condensed). The pure water molecule enters into the steam state and then condensed. It isn't without some flaws. Although it is supposed to be pure water, there are some small ions that can go along with droplets in the steam. Further purification is to distill the distilled water again (double-distilled water).

Each process has advantages and disadvantages; there are maintenance requirements, material replacements or regeneration, and the need to consider how much water may be wasted or lost in each process.

But before you go through all the above and produce such pure water, the question that needs to be answered is, "How pure does the water have to be to operate a successful marine system?"

My FOWLR systems don't require more than a single resin treatment and RO with a carbon polish. The quality of water is very much relative to what marine specimens you want to keep and maintain.

After all the efforts to obtain/create pure water, we add artificial salts to it which for the most part have impurities in the mix. It produces salt water which doesn't match natural sea water components but which (we think) doesn't negatively impact our success.

So how much is enough?

[Samper]

Lee thank you very much for the reply. I know that it is very well maintained as it produces all of the distilled water needs for the entire lab sciences building the aquarium sits in. As I mentioned I'm not registering any Cu with my Salifert kit but from what I've read it is possible Cu ions can still be present and this is my biggest concern. I did get a chance to take a look at the DI unit. It's a very large canister filled with DI resin but without the RO feature. It's much slower than the still but still produces at a decent rate.

After reading your post I called Barnstead Intl. The guy I spoke with on the phone from tech support is a reefkeeper and actually gets his water for his system from this very same model as do a few others that work there. The company does perform compresensive analysis of water samples for free. They are sending me a vial and prepaid return package. Thank you . On a side note I produced water much faster than the unit states. 10gph is what it says it produces but I produced 28 gallons in 17 minutes . This is another reason I am holding off on using it until the analysis.

Product specs on this still.

PRODUCT DESCRIPTION
• Designed for durability and consistent quality.
• The Classic Still was originally designed over 100 years ago, and has withstood all the tests of time.
• A low water cut-off on electrically heated stills prevents still burn-out in the event of feedwater interruption.
• Manufactured from copper and bronze, with a coating of pure tin. Pure tin is used due to its inert properties against the corrosive nature of pure water. Pure tin will also not leach any contaminants into the water.

Common Features of Electric Classic Stills A1011, A1013, A1015, A1016 and Steam A1212, A1213
• Feedwater preheated in condenser conserves energy.
• Double-walled boiler conserves electricity.
• Inert pure tin water pathways assures product water quality.
• Vented condenser allows for stripping of gaseous impurities.
• Unique deconcentrator removes scale forming impurities from the boiler.
• Q-Baffle® ensures high quality pyrogen free product water by stripping contaminant laden water droplets from steam.
• Space-saving horizontal condenser.
• Bench, floor, or wall mounted.
• Metal construction withstands years of use.

Specific Features of A1011, A1013, A1015, A1016 Electric Stills
• Operates on a wide variety of electrical services.
• Capacities range from 1, 2, 5 & 10 gallons per hour.
• Many options are available which include fully automatic controls.
• Includes low water cut-off to protect heating elements from burn-out when water supply is interrupted.
• All stills require 2 separate input power supplies; 120V supply for low water cut-off and rated voltage for contactor and heating elements.

Specific Features of A1007 Economical Electrical Portable Stills
• Produces high quality distilled water at the rate of .5 GPH (1.9 lph).
• Ideal for educational and other labs with moderate pure water requirements.
• Requires no permanent plumbing or electrical connections, and can be set up for operation in minutes.
• Includes low water cut-off safety protection.

Specific features of A1212, A1213 Steam Stills
• Utilizes available in-house steam as heat source.
• 5 & 10 GPH sizes available.
• Bench, floor, or wall mounted.