RO water with nitrates??

[Drpistak]

I am having a bit of a problem with high nitrate readings in my 300l tank approx 50 ppm and have been trying to reduce this with regular water changes 30l every 2nd or 3rd day. I have managed to reduce this to 25 ppm but by now I have turned over the entire tank volume with water changes. I have a 6 month old small RO unit with a carbon and sediment prefilter. I tested the output water for nitrate and it reads 10 ppm. Does this mean that my RO membrane has bit the dust or is there some other explanation? Shouldn't an RO membrane last longer than 6 months?

 

[Willy]

If it doesn't pass through DI resin a detectable nitrate reading is possible. If I'm wrong on this, maybe someone else can jump in with the right info. I would suggest getting an add on DI cartridge to add to your existing RO system, this will give you pure water..HTH

 

[burning2nd]

hmmm..... i can say with some certainty that no3 in your clean unmixed ro water is bad...

do you have a TDS meter? If not you should get a hold on one and figure out what your input and output is b4 and after your hole ro...

do you have DI? you might wanna get your self a sediment filter first then your filters and ro.. and then a Di last.

whats your input Pressure and temperature?
where does your water come from? the ground or city?

can your backflush that Ro?


sorry to ask so meny questions... but questions often answer other questions

 

[burning2nd]

not only is it bad... but to some degree... doing water changes with anything in it.. (no2,no3,ph4) kinda defeats it self... you will only achieve the lowest level, which will be your source water.

if your waters reading 10.. you will never get lower then 10 with waterchanges.

 

[Boomer]

I'm sure you have a testing error. I don't buy 10 ppm on the RO output at all. And if you have that much, then there is something very, very, wrong with that RO unit and it is not woking correctly at all. A RO will remove 95 % of NO3-. Some water supplies can have up to 50 ppm NO3-. So, math wise, your 10 ppm would eqaute to a RO NO 3-input of 200 ppm, not even so. Measure the RO input or tap water and see what you get for NO3-. RO membrans should last for years.

 

[tcduongxx]

I have RO membrane last two year and other last three. Depend on the quality of your filter and the quality of you source water.

I screw up my tank before becasue I did not check the RO out put.

Replace all RO components and do lot of water change to your tank to clean it up.

Most place recommend replacing pre RO filters every six months depend on the amount of use to extend the life of the RO filter.