RO Reverse Osmosis

RO Reverse Osmosis


Quality and affordability of water filtration systems improved incredibly in recent years. Complete units are inexpensive in the long run and can be used continuously for three to five years. Produced water can be used for cooking and drinking as a healthy substitute for always degrading tap water supplies. For aquarium use we are no longer limited by tap water parameters. Thanks to RO technology we can make any water parameters.


FAQ


Is RO filter wasting water?

RO filters are not wasting water when used with aquariums. Here is an example of cleaning up 400L aquarium from 600 µS to 340 µS with tap versus RO.


With 330 µS tap

30% WC, 600 -> 510 (- 90)

30% WC, 510 -> 450 (- 60)

30% WC, 450 -> 410 (- 40)

30% WC, 410 -> 383 (- 27)

30% WC, 383 -> 365 (- 18)

30% WC, 365 -> 353 (- 12)

30% WC, 353 -> 345 (- 8)

30% WC, 345 -> 340 (- 5)

Total amount of used water ≈ 1000 L


With 10 µS RO

30% WC, 600 -> 403 (- 197)

16% WC, 403 -> 340 (- 63)

Amount of used RO clean water ≈ 200 L

Amount of used RO waste water ≈ 800 L at 1 : 4 drain ratio.

Total amount of used water ≈ 1000 L


Cleaning up aquariums with tap and RO uses the same amount of raw water.


Isn’t drinking RO water bad for us?

No. It’s clean as rain and fresh spring water. RO filtration is the future as world water supplies deteriorate.


Why would one need RO water?

Some tap waters contain harmful substances to plants and fish.


Do plants grow in RO water?

Plants are thriving in RO water with fertilizer dosing and RO Essential Minerals reconstitution.


How to start PPS-Pro with RO and TDS?

Continuously, the RO water with Essential Minerals will be replacing the previous tap water. At the same time daily fertilizing will continue as recommended. Monitoring TDS or Conductivity will determine water changes.


RO Essential Minerals need to be added at 3 dGH based on the new RO water volume. Water changes are due when TDS readings exceed 125 ppm as NaCl ( 75 RO Essential Minerals + 50 fertilizer limit ) or Conductivity readings of 250 µS ( 150 RO Essential Minerals + 100 fertilizer limit ).


How to reconstitute RO water?

Demineralized water, RO water, rain water and very soft waters have inadequate essential minerals Ca, Mg and K. These deficiencies can be restored by adding PPS RO Essential Minerals. This will reconstitute RO water back to the natural water levels and ratios. The usual level is 3 dGH. Add 5 grams or 1 tsp per 10 gallon or 40L of new RO water.

(Not for PPS-Classic, please see “How much CaSO4 for PPS-Classic?” section bellow)


Why PPS RO Essential Minerals?

It is necessary to reconstitute RO water properly. Unfortunately, some products don’t follow natural water mineral levels and ratios. For instance, the usual natural water Ca : Mg ratio is 4 : 1. Some products have ratios as high as 7 : 1 and as low as 2.4 : 1. Another problem is enormous K concentration. With 6 dGH you get 8 x the average tap K level. This 70 ppm of K concentration is unnatural and may be responsible with the unusual ratios for some aquatic plant problems.

How much CaSO4 for PPS-Classic?

Generally plants take Calcium and Magnesium from water. A good source of Calcium is CaSO4 addition. It dissolves in hours and has no side effects. Magnesium is included in PPS so we don’t need to worry about it.


For PPS-Classic the recommended Ca level is 20 – 30 ppm and can be dosed after water change or once a month. Plants need very small amounts of Calcium.


41 gram / 100 gallon -> 30 ppm

11 gram / 100 litre -> 30 ppm


For PPS-Pro please see "How to reconstitute RO water?" section above


Are there other than CaSO4 calcium sources?

Yes but they are not as good as CaSO4. For example CaCO3 takes days to dissolve with cloudy water and also increases KH. Some sensitive plants don’t like CaCO3. Next is coral that doesn’t work for plants as well because increases KH and sodium levels. Next is CaCl2 that works for most plants but must be cleaned with water changes periodically because of high Cl content. And finally there are substrates with calcium that plants can adjust to and use as a source. Only drawback is KH increase which can be controlled with water changes, recommended maximum KH is 2 - 3 degree.


Is magnesium to calcium ratio important?

The most common Ca:Mg ratio in natural waters is 4:1. Though some plants don't do well in higher Mg levels.


Do I need to dose baking soda to increase KH?

No. There is no need to worry about KH unless you have African Cichlid fish. Plants and soft water fish prefer low KH water. Less chemicals better.


How do I increase KH?

3.6 g per 10 gallon or 40L of baking soda NaHCO3 will add 3 dKH


Do I need to test for KH?

No, unless you have KH leaking decoration, rocks or substrate. Then test for KH periodically and determine how often water change need to be done to keep KH under control. The recommended maximum level is 2-3 dKH.


Do I need to add pH buffer?

No. It does more harm than good in planted aquariums.


What about pH crash?

RO water just like rain water does not have any KH buffering to regulate pH. Still, do we see dead fish after rain in the nature? No. Because it is natural, plants and soft water fish love it.


Is RO unit expensive?

No, because it produces huge quantity of water in its life time. The main cartridge can be ran 24/7 for three to five years. The only maintenance is to replace one mechanical and one carbon filters twice a year.


How do I know my RO filter is ok?

The best way is to test water conductivity with Total dissolved solids TDS meter. A good RO filter performance is 1 – 10 µS.


Any recommendation on RO units?

Hook up two pressure gauges, one before RO unit and one before main RO cartridge. Check for difference in pressure, the actual loss of pressure caused by pre-filters as this is the main cause of failure. Another available item is DI cartridge which is unnecessary for planted aquariums.