Remember To Test The Output From Your RO Unit

Not more testing! Those aquarists with a reef aquarium will no doubt feel that they do enough already.

The testing here is not of the aquarium seawater, it’s what goes into the aquarium in the form of routine seawater changes and evaporation top-ups. These routine seawater changes are designed to assist in maintaining high quality by replacing at least partially trace elements and ‘freshening’ generally. Taking this into account there doesn’t want to be anything being put into the aquarium that could be detrimental to it.

Some aquarists use tap water and hopefully have tested it to see if there is an excess of nitrate and/or phosphate etc. If there is the advice is to use an RO (reverse osmosis) unit. This device is a filter, where fresh tap water is forced through a semi-permeable membrane. Very nearly only pure water is allowed to pass, the purity of the output is usually 95 to 98%.

The RO unit in action is simple to use and requires very little maintenance. Now and again at the manufacturer’s recommended periods the carbon filter is changed and also the sediment filter though this can sometimes be cleaned. The time span for this maintenance depends on usage but can be very many months.

There are tests that need to be performed on occasion of the output from the RO unit, again not very often. The tests are usually nitrate and phosphate and the check is done on the purified output from the unit. One occasion when the test should be done is when the carbon filter (and to a lesser extent the sediment filter) have not been changed for a while, and the running period is longer than the manufacturer’s recommendation. This is because the carbon filter is there to protect the membrane from chorine. Chlorine can damage the membrane and reduce its efficiency, permitting unwanted substances to pass through it. So it needs to be tested to be sure that it remains fully effective.

Another occasion when these tests need to be done is if the filter has been allowed to dry out. A membrane can be damaged in these circumstances again permitting unwanted contaminants to pass.

If the aquarist does the simple maintenance at the periods recommended by the manufacturer – these periods are often based on gallons of purified water produced – then it is unlikely that there will be a problem. If the membrane becomes less than fully efficient it is often best to purchase a new RO unit, as the membrane makes up the major part of the price.

As with other areas attention to maintenance will maintain peak efficiency.


Remember To Test The Output From Your RO Unit
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2 Comments
  1. Nice read. I have both an inline TDS meter and a nice handheld COM100 TDS meter. The inline is hooked up before / after the DI cartridge, and as soon as I start seeing 1 or 2 TDS, I replace all filters. The in-lines are great for quick looks, but times it’s read 2 or 3 on the in-line, the handheld COM100 will read 7 or whatever. Problem with handhelds is that they can get tossed in a drawer and forgotten, so I’d definitely recommend having inline meters as well.

    My filters (carbon, micro sediment, and DI) usually last me on the order of 6 – 8 months, and if I need to change one, I’ll just save a headache and change them all. The membrane, however, is a different story. Mine is still going strong, though I do have a flush valve which I use for 30 seconds to 1 minute before AND after making water, every time.

    stonyreefs last blog post..Decisions… or, Fluke Tabs and Sad Clowns?

  2. Thanks for the comments.
    You’re certainly on top of the game!

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