from Advanced Aquarists Online Magazine
SPS corals require different water parameters than soft corals do, for their survival, and especially for their maximum growth. They prefer to have close to zero measureable Nitrates, because these Nitrates can inhibit the building of their skeleton. in other words, the calcification of their skeleton can be slowed or stopped by higher levels of Nitrates in the system. So it's very important that both nitrates and phosphates be zero or as close to zero as possible.With reduction of nitrates/phosphates SPS corals have been reported to increase in color pigmentation. High nitrates
anything detectable on a standard hobby test kit will cause some form of colour change. Usually browning due to the rapid reproduction in Zooxanthellae.
Elevated trace elements
over dosing with these besides causing algae blooms will again cause a increase in Zooxanthellae production.
Nitrate levels in aquariums are much higher than those in the ocean. The average nitrate levels of the ocean is 0.1 ppm at depths up to 50 meters, and 2.5 ppm and higher in deeper regions. But in the South Pacific reefs where we get most of the creatures we want to keep, nitrate levels average around 25 ppb (that’s parts per billion) which is equivalent to 0.025 ppm. So here’s the first problem: a typical hobby nitrate test kit can only go down to about 1.0 ppm, which is a nitrate level 40 times higher than what we’re shooting for. If you test for nitrates and the test vial looks crystal clear and colorless, your nitrate level could still be a hundred times higher than the ocean levels.Surprisingly, reef tanks and most corals need nitrates to survive. The zooxanthellae present in all photosynthetic corals are algae. They need nitrates to grow. But when nitrate levels are too high, it causes an explosion of the zooxanthellae population within the host coral and in turn, actually decreases the rate of growth of the coral. This begins to occur in some SPS corals when nitrate levels reach a low 0.5 – 0.7 ppm. LPS and many soft corals can tolerate 3-5 times this concentration with no ill effect. At 5.0 ppm and higher, nitrates become poison to many SPS corals. To make matters worse, high nitrates cause runaway film algae which covers the skeleton and polyps of these corals, exacerbating the problem.Feeding corals is more prone to nitrate production than feeding fish. Target feeding helps concentrate foods at the coral, but most of it winds up in the water column to decompose. The worst feeding technique is to dump filter feeding foods directly into the tank. A very small percentage may arrive at a polyp, and the rest just fouls the tank. But PLEASE- don’t stop feeding your corals for fear of elevated nitrates. There is no additive in the world like food to give your corals extended polyps, better coloration, and an overall healthy appearance. You need to balance nitrates from food with effective ways to remove it.
i know things are changing in the hobby everyday,but i would think the vast majority of us would never do anything to raise nitrates in our systems,just too slippery of a slope!
i would venture to say that you are adding a LOT of 'stuff" to the water and it could be a water quality issue even without nitrates or phosphates.i know thats how we measure it but that is not the only tell tale sign of bad water quality.it seems to me that you would have concentrations of these far greatter than nsw.to be as close to nsw as we can is what we should all be striving for.but with all that said,i still think those sps pictured looked real good to me.
