Does topoff RODI lower nutrients?

[ilikefish69]

When our water evaporates, we know it does not take the salt with it. But I can't find definitive answers on topping off and lower nutrients. Nitrates being tested in parts per million, and those parts being water molecules ( I assume ).

For example if I have a 5 gallon tank with 30 ppm nitrate, and over the course of a week I am topping off with 1 gallon of water. Depending on filtration and bio-load, would the 30 ppm drop with the addition of 0 TDS water with levels of 0 no3?

I am operating on a much larger scale, 125 and am using over a gallon a day to top off. I do not have high nutrient levels, but it is more curiousity than anything. I like having an open top aquarium, instead of a lid I have a 10" canopy that goes around the tank, so if the fish jump (or have already tried), they would hit the wood and bounce back in the water. Never seen it happen, but I am sure it has.

If there are 30 ppm (part per million) registered, and you add in more "parts" which I assume would be the h20 atoms, then simple math would have that ratio reduced.

if there are concrete examples or case studies I would be very interested in them.

 

[Saltyreef]

When our water evaporates, we know it does not take the salt with it. But I can't find definitive answers on topping off and lower nutrients. Nitrates being tested in parts per million, and those parts being water molecules ( I assume ).

For example if I have a 5 gallon tank with 30 ppm nitrate, and over the course of a week I am topping off with 1 gallon of water. Depending on filtration and bio-load, would the 30 ppm drop with the addition of 0 TDS water with levels of 0 no3?

I am operating on a much larger scale, 125 and am using over a gallon a day to top off. I do not have high nutrient levels, but it is more curiousity than anything. I like having an open top aquarium, instead of a lid I have a 10" canopy that goes around the tank, so if the fish jump (or have already tried), they would hit the wood and bounce back in the water. Never seen it happen, but I am sure it has.

If there are 30 ppm (part per million) registered, and you add in more "parts" which I assume would be the h20 atoms, then simple math would have that ratio reduced.

if there are concrete examples or case studies I would be very interested in them.

Heres a good read.

"Inorganic nitrate (NO3-) and nitrite (NO2-) are water soluble (as a result of their interaction with the positively charged portions of polar water molecules) (Figure 1) and commonly exist as salts of nitric acid and nitrous acid, respectively. "

It sounds to me that nitrate bonds to the hydrogen molecule but will remain after evaporation as they are solids/salts.

Nitrate/Nitrite Toxicity: What Are Nitrates and Nitrites? | Environmental Medicine | ATSDR

www.atsdr.cdc.gov

 

[Dburr1014]

The most important thing to remember is evaporation is only water(h2o), nothing else.
So your numbers will not change if you keep your water level the same height.

If your water lowers due to evaporation, the nutrients will be higher.

 

[mdb_talon]

Makes no noticeable difference. I guess most accurately as water evaps then your nutrients go up (in ppm terms) very slightly and then you top off and dilute it then they will drop very slightly.

 

[ilikefish69]

Makes no noticeable difference. I guess most accurately as water evaps then your nutrients go up (in ppm terms) very slightly and then you top off and dilute it then they will drop very slightly.

That makes a lot of sense. Using the reefbreeders ATO, and a fairly large sump, the last chamber will drop 2” or so before pump kicks on and it fills a lot of water. But the nutrients are going to be present and relative to a level of water when the tank is topped off.

kind of embarrassed, I did not account for the minor increase in levels as evaporation occurs, the top off water just puts the tank back to “standard operating levels” but with as much water volume as I’ve got, the peaks and dips are less than I feel like messing with measuring.

good answers, thank you all, great forum and great people