Nitrate Question

Andyoybna · 02-03-2007, 12:43 PM

ok so recently i tested my tap water, not sure why it has taken me so long but.... I'm getting 40ppm Nitrate out of the tap. Now I've heard time after time that the ONLY way to remove nitrate is by water changes, if this were true then my tanks should be right around 40 ppm of nitrate all the time which is at the high end for saltwater and decent for fresh

So i was checking my params in my nano reef today and I find 10 PPM nitrate so where did it go? is it possible for nitrate to gas out with high aeration? or maybe my algea is using it as plant food? do any corals use it? I'm just confused since my params are

0ppm Ammonia, 0ppm Nitrite, 10ppm Nitrate

If my tap water has 40 PPM of nitrate, essentially a water change would actually raise my nitrates

realistically after substate and live rock there is about 7.5-8 gallons in the tank maybe less who knows

lets call it 8 for math reasons, say i take 2 gallons out to do a water change and 40 ppm of nitrates is in those 2 gallons it would then almost double my nitrates to about 18 ppm if my math is correct

Now.... looking at this water changes seem detrimental since the main thing you are trying to acclomplish with water changes is reducing the nitrates, it seems that all i should do is to keep supplimenting the water with calcium, trace elements and iodine and i should be good, but sadly... topping off will also add to the nitrates.

so my 2 questions are

how are the nitrates being removed

and can I apply that to my tap water before I use it so I don't raise nitrates by doing water changes

Loman · 02-03-2007, 01:08 PM

Andyoybna

There are a couple things you post raises.

Regarding Nitrates I think you are basically correct that adding salt made from your tap water to a tank with 10ppm would add Nitrate. This is one of the reasons that we often encourage salt tank owners to use RO or distilled water if it is a reasonable option. Once your tap water passed through an RO unit the Nitrates should be 0. As for where do they go. I suspect you have a good base of biological filtration that has been in place for while. These will develop zones where anaerobic (non-oxygenated bacteria) live. They will convert Nitrates to Nitrogen gas which then bubbles harmlessly out of the water. The algae etc. could also consume some of the Nitrates.

Thew one point I disagree with you on is that water changes are ONLY to lower Nitrate. That is clearly a big part but simply removing debris and other material floating in the water or laying on the floor is also a big part of the need to change water. If you quit doing water changes your water will begin to yellow from the accumulation of urine, decaying food etc. You will need to continue water changes so this gunk does not build up. I have seen situations where the after parameters looked good and the water color and odor where not very good at all.