Marine Aquarium Acronyms: RO/DI Defined

As most marine aquarists will tell you—and as we point out frequently here at Saltwater Smarts—using purified source water for initial aquarium fill-ups, partialwater changes,淡水top-offsessential to maintaining the best possible water quality in a saltwater system. One of the more common methods hobbyists use to achieve this “purified source water” is reverse osmosis/deionization, better known as RO/DI.

什么是反渗透？

反渗透（RO）涉及将水从水龙头中迫使水通过半透明的膜，该膜使水分子可以流过，但排除了溶解在水中的污染物和杂质。

This process is called reverse osmosis because water passing through a semipermeable membrane normally flows from an area containing a lower concentration of solutes to an area with a higher concentration of solutes. Pressurizing the water on the side of the membrane with the higher solute concentration reverses this process.

什么是deionization？

Deionization (DI) involves passing the tap water through a dionizing resin, which bonds with the charged ions of dissolved contaminants and thereby excludes them from the product water.

多阶段

While RO and DI units are available individually, they’re more commonly purchased as part of multistage systems that often incorporate a sediment filter and a carbon block filter ahead of the RO and DI components. These systems are usually rated according to the number of gallons of purified water they produce per day—35 GPD, 60 GPD, 100 GPD, etc. Many also come with a TDS (Total Dissolved Solids—whoops, there’s another acronym!) meter for testing the purity of the product water.

If it’s good enough to drink…

对于人类消费的水来说，对于海洋生物来说，适合人类消费的水似乎是合乎逻辑的。不幸的是，情况并非如此。氯/氯胺，硝酸盐，磷酸盐，铜，铅和农药或除草剂的痕迹只是对自来水中可能存在的污染物的抽样，并且可能对敏感的海洋生物有害（如果不是致命的）。多阶段RO/DI系统将消除所有这些杂质等等。

但是我的朋友只使用氯化自来水就可以得到！

If you live in a municipality that boasts tap water of exceptionally high quality, it may be possible to get by simply treating the water with a dechlorinator/dechloraminator before using it in your saltwater aquarium. But this approach is a major gamble—especially if you plan to keep corals and other sensitive invertebrates.

为什么？可以在自来水中存在的一些污染物（例如铜）对珊瑚和其他无脊椎动物完全致命。其他（例如，硝酸盐和磷酸盐）可以为不良藻类开花。更不用说，您的公用事业公司可能会在不通知您的情况下更改其水处理协议，因此，纯净的自来水突然不是，因此您的牲畜可能会遭受损失。

消除猜测

The source of water quality issues, such as elevated nitrate or phosphate levels, can sometimes be difficult to pinpoint and resolve. If you routinely purify your tap water with a quality, well-maintained RO/DI system and you do run into problems, you can pretty much rule out your source water as the cause of the issue right off the bat. That helps eliminate a lot of guesswork and allows you to focus your troubleshooting efforts more effectively.

What to do with all that waste water?

RO/DI单元的一个缺点是，它们往往比纯化的产品水产生的废水要多得多。允许所有废水流下排水口，这确实可以以错误的方式摩擦思维意识的业余爱好者。有些人发现这种水的创意用途，例如浇灌花园和室内植物，洗车，冲洗厕所等。但是，不断提出实际用途可能会具有挑战性。

Perhaps some of you experienced salties out there have other uses for RO/DI waste water to recommend? Or, maybe you’ve heard of newer RO/DI technologies that minimize this waste? If so, we’d love to hear from you in the comments section below.