High Nitrates in RO/DI Water

[snaredrum]

What levels should I expect from RO/DI water. Here's what has happened. I have been buying RO/DI water from a local supermarket. I decided to test it after I noticed some hair algea starting on one of my rocks. Phosphates are at 0. Nitrates are at 20ppm. Is this normal?

 

[snaredrum]

No ones ever checked their NO3 levels in RO/DI water?

 

[mr. limpid]

IMO store water is made for drinking not our fish tanks. I stop buying water from the store because of large algae growth. IMO I would buy from the lfs b4 buying from the store. If you have the room add an RO system saves you time and money in the long run. And you control the quality of the water. Good luck

 

[lexluethar]

That is not normal. Even though is was bought from a store if it is RO/DI water then it should have zero's accross the board. I noticed every once in a while the water from my LFS has a tiny trace of ammonia. Not sure how or why. I would continue to buy from that store and test the water right after purchase. Maybe how you are storing it is contributing to your Nitrates.

 

[perfectdark]

Very odd indeed I have never got any readings from my RO water. All zero across the board. But I buy my water from my LFS not a supermarket. I dont really know how often if at all you are supposed to change the filters out on the RO units maybe thats an issue where you are buying your water from.