So I never thought I would find myself posting in this area...

No the NO3 are better in the tank then what the tap water will maybe add to the tank.. And the water treatment will drive the skimmer crazy , Take the time to make the change with good quality water.

 

+100 as they all say, nothing comes fast, take time to it right.

 

I agree, 18ppm is NOTHING to worry about, I had 20ppm for yrs with no ill effects. 18ppm of No3 is something that your over looking like; over feeding, filter cleaning, reg. WC's or not cleaning out the sand bed. Luna

 

18ppm is nothing for a fish only tank (assuming it's fish only). Don't worry too much about water changes unless it is in the red zone. Think of it this way, if you performed a 10% water change, your nitrates will only drop by ~2ppm (I am rounding up, of course), so you will still have 16ppm of nitrates. That assumes your tank doesn't produce anymore nitrates either. If you are in dire need of dropping nitrates, like in a case of >40ppm in a reef, you are better off using a bacterial product like Cycle than a huge water change. A huge water change can throw off the water chemistry (Mg, Ca, Alk) than adding beneficial bacteria to aid in the nitrifying process. If I remember right, even Tangster doesn't do water changes and lets things heal itself as naturally as possible.