I Was Doing A Routine Water Change.i Did A Water Test That Showed A Higher Than Normal Nitrate(30)level.i Changed 20 Gal. On A 120 Tank.after Doing The Water Change,i Tested Again.now I Am At 100.i Did Another Water Change Right Away.i Changed Out Another 30 Gallons.still Around 100.what Am I Doing Wrong?
First, test your source water as mentioned for NO3. Then test your mixed SW that you use for water changes. Aside from that, its the usual suspects for NO3 accumulation...over-stocking, over-feeding, too little bio-filration, etc.
Some people are like slinkies...they serve no real purpose yet can still bring a smile to your face when you push them down the stairs!:p
Have a great day! Brian