I use instant ocean also, largely for the reason that there are no additives.@rygh I am not sure if I gave them in my tap water, I do have a DI stage and it was changed about a month ago maybe more...based on the color change of the resin it is still good only about 1/4 of the bottom has colored as being spent...but I cant say for sure there aren't chloramines getting passed it...how would I check for this is there a test?
Also I am using regular instant ocean salt mix...I have not known or heard of them using any amino blend or labeling as any "marketed additives" (such as the reef crystals).... I don't think Instant ocean is suppose to contain these things. I think the chloramines is worth a look at if they can commonly find there way through di resin....I will have to obtain a water quality report from the water company to comfirm them in the city water....thanks
The DI resin should take care of most contaminants that make it through.
So much for those ideas.
To track it down, I would start testing things for ammonia, not nitrate.
Or better yet, check both. It is likely nitrates are starting out as ammonia.
Check RODI fresh water as it comes from RODI.
(That will prove it is from RODI system or not)
Fill mixing barrel with RODI, let it sit for a day or two, then check it.
(That will prove if you have contaminants in barrel or mixing pump)
Check salt mix right after mixing.
(That will prove if you have a bad batch of salt)