Nutrient Levels

[Zerobytes]

Good morning.

I'm only asking this as as I'm curious, so thanks for taking the time.

Anyway, is there really a difference in NO3 or PO4 being anything above 0 as opposed to some higher level ? If both are readable and above 0 doesn't that mean there is excess available and it is all not being used (and therefore your are good)? Or does more excess result in more consumption and thus preferred?

I'm certainly not planning to try to run both close to zero but just interested.

Thx!

 

[Nano sapiens]

Considering that our hobby grade test kits have a minimum detection limit (below the limits we can't definitively tell if we still have that element in the water column, or not), excess of anything just means it's available. If you have a bit more of an element, then it is less likely to be depleted in between the additions of that element. Too much of anything can cause other issues, of course, so moderation is advised.

 

[Zerobytes]

Considering that our hobby grade test kits have a minimum detection limit (below the limits we can't definitively tell if we still have that element in the water column, or not), excess of anything just means it's available. If you have a bit more of an element, then it is less likely to be depleted in between the additions of that element. Too much of anything can cause other issues, of course, so moderation is advised.

Thanks for the response!

I was more referring to opinions folks may have where, for example, .08 is better than .03, not from a practical standpoint like you mention but rather from the fact that it is "better" for the corals and such. Just trying to understand for example, if measurements are exact is .08 really better than .03? In both cases you have excess that is not being consumed.

 

[Randy Holmes-Farley]

Good morning.

I'm only asking this as as I'm curious, so thanks for taking the time.

Anyway, is there really a difference in NO3 or PO4 being anything above 0 as opposed to some higher level ? If both are readable and above 0 doesn't that mean there is excess available and it is all not being used (and therefore your are good)? Or does more excess result in more consumption and thus preferred?

I'm certainly not planning to try to run both close to zero but just interested.

Thx!

More than a fixed amount (which varies by organism) means there is excess. It might have other undesirable effects, but 1 ppm phosphate does not spur algae more than 0.1 ppm.

 

[Dan_P]

Good morning.

I'm only asking this as as I'm curious, so thanks for taking the time.

Anyway, is there really a difference in NO3 or PO4 being anything above 0 as opposed to some higher level ? If both are readable and above 0 doesn't that mean there is excess available and it is all not being used (and therefore your are good)? Or does more excess result in more consumption and thus preferred?

I'm certainly not planning to try to run both close to zero but just interested.

Thx!

OPINION.

When the PO4 concentration is roughly constant for a system, it means the amount being put into the system is balanced by the the amount being exported plus the amount being accumulated by the system but “hidden”. The accumulation includes PO4 being assimilated, i.e., converted to biomass, and the amount adsorbed to aragonite and and other substances that phosphate ”sticks” to. The measured amount of phosphate only provides information about the net amount and not the amount potentially available for nuisance organism growth.

The situation is a bit different for nitrate. Nitrate levels are certainly connected to how much nitrogen comes in and how much is accumulated and exported, but other very important nitrogen compounds like ammonia and organic nitrogen compounds are circulating undetected in the system, and available to feed nuisance organisms before any excess is even converted to nitrate. This is why nitrate concentration itself is a poor predictor of nuisance organism growth. The nitrogen economy, which we think nitrate plays a very important role, actually uses another currency that we never see. The nitrate we measure is probably only a small amount of the total amount of nitrogen being circulated among the organisms. Maintaining a certain nitrate level may or may not be important. It probably depends on the size of the cryptic nitrogen economy which we know little about.