0 nitrate = less vivid coral colours?

[serbusfish]

Im not sure if my skimmer is too efficient for my tank size but my nitrate is always at 0, and I was wondering if this could affect the health of corals and perhaps reduce their colour? My SPS are all exactly the same as when I bought them, as are most of my softies (although my Clove coral looks a bit duller) however some of my LPS (Torch, Duncans, Elegance) dont seem to have the same vividness that they had when I first purchased them, in fact the Torch looked noticeably duller within 4 days of adding to the tank.

The corals are all still growing well and seem healthy, I just want to increase their colour if possible. Perhaps I need to feed more? Or even add more fish to the tank? My skimmer is rated for a 155 gallon tank, mine is 75 gallon.

 

[toothybugs]

How long has everything been running, how old are the frags, and what test kit are you using?

 

[Azedenkae]

I think it also depends on exactly that '0' nitrate is saying. Some may have zero nitrates, but are feeding heaps. Just that their filtration is good enough to keep up with all that. In that case they may have zero nitrates but corals do great thanks to good feedings. On the other hand someone else may also measure zero nitrates, but the actual amount of food a coral gets would be low, hence low growth.

*Shrugs*

Hard to say exactly.

 

[tmz]

In a fed tank a nitrogen deficiency would be rare. The fish respire ammonia, the food brings in nitrogen too ;so, some should be in transist. Feeding corals is helpful to them providing a variety of nutriints and elements. Excess dissolved nutrients are not.

Reef surface water is about 0.2 ppm nitrate.
Many tanks do fine with undetectable nitrate,which is not the only nitrogen source anyway.
Some folks do dose very small amounts of sodium nitrate usually when a nitrogen deficiency is viewed as limiting the growth of organisms that take up inorganic phosphate ,typically in systems being dosed with organic carbon to encourage extra bacteria.
Generally ,adding nitrate does not improve colors and can lead to browning from increased zooxanthellae density and bleaching in some cases if increased zooxanthelae provide more oxygen than the host coral can handle.

 

[CHSUB]

coastal water in miami, that is collected for me, measures 0 on a Salifert Tester, and i would guess the water over the reefs are even lower. imo, 0 no3 is fine, unless your using a test kit that reads very low levels?

 

[CStrickland]

I use my nitrates as one way to measure how well I'm balancing feeding and filtration. Like measuring leftovers. If it gets too high Im over feeding or slacking on cleaning. I never had it get too low but it seems easier to feed a bit more than to mess around with the filtration.

Like tmz said, when you are tweaking the phos carbon balance to lower nutrients by having a stronger biofilter, you would need to keep that balanced too.

 

[tmz]

This article provides a lot of information on nitrate and it's role in the ocean and our aquariums:

http://www.advancedaquarist.com/2003/8/chemistry#section-0

This is from it:

"...Concentrations in the ocean vary considerably from location to location, and also with depth.2 Surface waters are much lower in concentration due to scavenging by various organisms, and are often less than 0.1 ppm nitrate (not that all concentrations in this article are in ppm nitrate ion, and not in ppm nitrate nitrogen). Deeper waters typically range from 0.5 to 2.5 ppm nitrate. Surface regions where upwelling of deeper water takes place will also have these higher values...."

So, reef surface water will often be higher than ambient seawater water due to the nutrient upwelling that feeds the reef. It can be more than 0.2ppm which is the usual approximation.

 

[kewadiak]

I also wonder this same problem i never have any nitrates detected, but always have some sort of algae either film or green hair algae not bad but present i run GFO and carbon continuously. You here of people like to keep measurable traces of nitrate how do you accomplish this with out having algae? Do nitrates cause algae or am i wrong i always struggle with this concept and do feel i am starving my corals that my water is over filtered.

 

[tmz]

Algae needs nitrogen, yes; it also needs phosphate; corals also need both and other elemnts from feeding and some direct uptake from the water. Continuous aggressive gfo use can limit both algae and corals by limiting phosphate particulary when they don't have anything to eat.

The cited article discusses a variety of useful methods to control nitrate.

Personally, I've used sulfur denitrators with success as well as lit large macro algae refugia in the past .

I've relied on dosing organic carbon( vodka and vinegar) for the past 6 years or so to keep phosphate and nitrate low( PO4 / 0.02 to 0.04ppm and nitrate at or less than 0.2ppm) in a heavily fed system with no mechanical filtration; just skimming and relatively small amounts of GAC( granulated activated carbon) and several cryptic refugia. In brief ,the extra organic carbon increases bacteria which take up nitrogen and phosphate ; they add to the food web in teh tank and are also exporte along with the nutrients they hold via skimming.

 

[serbusfish]

How long has everything been running, how old are the frags, and what test kit are you using?

The tank has been set up since March 13th, cycled within 1 week as I used 100% live rock, and the corals vary in age, the Torch has been in the tank 2 weeks, but the Clove polyps were added near the end of March. I use salifert test kits. The majority of my corals are as vibrant as ever, my Candy Cane is bright green/yellow, Favia is deep green, Plate coral is green/red.

Its just a few that seem to be a bit duller, my Elegance corals tentacles were pink but are much paler now, although it has grown a lot since I bought it. The greens on my duncans are very dim, and as I mentioned my Torch isnt as vibrant as when I put it in the tank. Im not sure if it is my lighting, or nutrients, or what, I run 4x 54w T5's and a phosphate reactor, LFS used a low range kit to test it and its reading at 0.075 so im going to change the media tonight.

 

[nuxx]

I'm trying to keep our nitrates in the 5-8 range for coral.