Ro Unit And Nitrates

[DarrenUnwin]

Hi all,

I have a quick question regarding my RO unit which I purchased about 9 months ago,

Basically I thought I would test the water it produced just to check what the readings were prior to me adding to the tank. I found all readings to be zero nitrite, phosphates etc but did see the presence of Nitrates (the reading was around the 5PPM mark).

Am I right in thinking a RO unit should remove Nitrates in which case do I have a faulty RO unit, or a faulty test kit?

Any advice would be greatly received

 

[andywg]

Most likely it is a faulty test kit. I've had one test 5-10ppm nitrates on RO water. I find that nitrates kits are far from accurate at the best of times.

To better test the efficiency of an RO unit you need to employ a Total Dissolved Solids Meter (TDS). The TDS will let you know when the membranes are starting to fail.

 

[SkiFletch]

What he said. TDS meter is the way to go. None of my test kits work on RO water. Try testing it with pH. One time it'll read 6, and the next it will read 8 .

 

[crazyelece]

first make sure the test kit you are using is for freshwater and not saltwater (common mistake). Next a TDS meter is definately the best option. Also if you have had it for 9 months you should have changed the sediment filters by now. It is usually recommended to change them at 6 months.

All most forgot, testing for ph on RO water is useless as all the buffering capability has been removed. In marine aquariums the salt mix adds this back in, but before that the ph can have a wild swing depending on exactly what little bits are left in the water. If you want it to test a ph of 7 you also need a DI filter to get the tds to zero.

 

[DarrenUnwin]

Guys,

Thanks for the advice, I've been away so not had chance to do much, but I have ordered new filters and will get new test kit next time I'm at the LFS

Cheers