RODI and high nitrates

[Ozziewog]

Just a note. Change your rodi filters! I just put in a new resin filter still in vac bag. Rodi read 0 ppm. Couldn’t figure out why nitrates went over 75 ppm. It was the water filter. Test your water before you mix salt, and after too. Almost killed my whole tank!

 

[revhtree Verified Admin]

Welcome to your new home for saltwater reef aquarium resources and fun! Welcome to the family! :D

 

[vetteguy53081]

 

[vetteguy53081]

Just a note. Change your rodi filters! I just put in a new resin filter still in vac bag. Rodi read 0 ppm. Couldn’t figure out why nitrates went over 75 ppm. It was the water filter. Test your water before you mix salt, and after too. Almost killed my whole tank!

The water filter may play a role but other causes are poor filtration , overfeeding, Use of tap water ( which may be in relation to your water filter) and algae blooms, milky water will often be the result.
75 reading will cause stress over death of the fish and if true reading

 

[Ozziewog]

Tap water was 1.1 ppm. I use tropic Marin pro salt. After all filters were changed and membrane ppm and nitrates were zero. After salt mixed ppm zero nitrates. Glad it caught it only lost one coral .

 

[backbayreef]

Tap water was 1.1 ppm. I use tropic Marin pro salt. After all filters were changed and membrane ppm and nitrates were zero. After salt mixed ppm zero nitrates. Glad it caught it only lost one coral .

Welcome to R2R! Glad you caught it and thanks for sharing. My nitrate was at 230 and didn’t lose a single coral since I have mostly softies and inverts. My anemones grew big and split multiple times! However, the issue with high N&P - corals don’t grow at all, believe me, I know! lol

 

[zheka757]

Welcome to R2R!

 

[Randy Holmes-Farley Verified Community Expert]

Tap water was 1.1 ppm. I use tropic Marin pro salt. After all filters were changed and membrane ppm and nitrates were zero. After salt mixed ppm zero nitrates. Glad it caught it only lost one coral .

I’m not really getting the cause and effect.

I’m not seeing how source water at 1.1 ppm gets a tank to 75 ppm, and I’m not seeing how 75 ppm is killing corals.

 

[Ozziewog]

I tested the ROdI water right out of the filter . Nitrates were over 75 ppm . After filters and membrane changed ppm for nitrates were at zero. I was doing water changes trying to get nitrates down but instead I was making it worse! Everything else parameter wise is spot on. After 40 gal change level down to 56.7. Going 15 gal change today to drop it more. Fish are fine but corals closed up. I have a 60 gal tank we’re 30 gal sump

 

[Randy Holmes-Farley Verified Community Expert]

I tested the ROdI water right out of the filter . Nitrates were over 75 ppm . After filters and membrane changed ppm for nitrates were at zero. I was doing water changes trying to get nitrates down but instead I was making it worse! Everything else parameter wise is spot on. After 40 gal change level down to 56.7. Going 15 gal change today to drop it more. Fish are fine but corals closed up. I have a 60 gal tank we’re 30 gal sump

I think there's a problem somewhere. The EPA guidelines would not allow 75 ppm nitrate in drinking water.

You literally said above that tap water was 1.1 ppm.

I suppose that the DI may have collected significant nitrate that was being displaced by other ions when the Di depleted, but I'd be quite surprised if it reached 75 ppm. Perhaps it was interference from a small amount of nitrite looking like a lot of nitrate.

 

[AndrewE]

I tested the ROdI water right out of the filter . Nitrates were over 75 ppm . After filters and membrane changed ppm for nitrates were at zero. I was doing water changes trying to get nitrates down but instead I was making it worse! Everything else parameter wise is spot on. After 40 gal change level down to 56.7. Going 15 gal change today to drop it more. Fish are fine but corals closed up. I have a 60 gal tank we’re 30 gal sump

I'm looking for some answers, too. I have a nitrate issue in my 120. I tested them because corals were closing up then dying.

I tested my RODI water and the result was the same as the tank so I was clearly introducing the nitrates from the RODI. I put a new membrane, as well as the other 5 stages. I did a huge wanted change (40 gallons), waited half a day and tested the water. No change, so I tested the RO water. It's the same as it was. I don't know how that could be possible. Any help is greatly appreciated. I'm at a loss and I'm losing corals.

 

[Jamie814]

I tested my RODI water and the result was the same as the tank

How are you testing nitrates? Some test kits cannot be used for both salt and fresh water.

 

[Shirak]

I'm looking for some answers, too. I have a nitrate issue in my 120. I tested them because corals were closing up then dying.

I tested my RODI water and the result was the same as the tank so I was clearly introducing the nitrates from the RODI. I put a new membrane, as well as the other 5 stages. I did a huge wanted change (40 gallons), waited half a day and tested the water. No change, so I tested the RO water. It's the same as it was. I don't know how that could be possible. Any help is greatly appreciated. I'm at a loss and I'm losing corals.

I am curious as to what you are measuring in the tank and in your RODI for NO3.
Are you getting 0ppm tds out of your RODI?

 

[Randy Holmes-Farley Verified Community Expert]

Tap water itself should not have more than 10 ppm nitrate N (44 ppm nitrate) per EPA guidance.