So today is the day of research (should have done this before hand). It seems that each of the levels is close to recommended. I do have a couple questions ...
1. Alk is a little low depending on the information you read. I have read that you can add Baking soda to elevate the Alk reading. I also read that for proper growth a lower akl reading should consider with lower Nitrate and PO4 readings (both of which I have). As Alk rises the water should be kept 'dirtier' to allow proper coral growth. Any insight into this? I was considering working to get Akl to 7 which is still considered on the low side (using Baking Soda) - again though due to the 'clean' water.
2. Calc is right on the high side. Is there a downside to this?
3. Mg is right on the high side. From the reading it sounds like Mg doesn't really hurt anything being elevated - more of a concern if the levels are low. Thoughts?
As a side note, the open brain is almost completely gone (80%+). Sucks...
1- Long story short, when you have high alk and Ca, corals can built their calcium carbonate skeletons faster. But doing so also requires building the soft tissue and symbiotic algae faster. So you need to have higher NO3 and PO4 to support that (Not dirty, but nutrient rich). If not, coral tissue starts to starve and since there is not enough NO3 and PO4 for both the coral and the algae, it expels algae and bleach.
In the opposite case, when alk and Ca are low, corals cannot built skeleton fast, so you need to have low NO3 and PO4 to prevent symbiotic algae from overpopulating coral tissue (which cause coral to expel them and bleach).
But keep in mind this is a very simplified explanation of the actual situation. It greatly depends on other factors such as light and how much suspended food particles are available. In nature coral reefs are very nutrient poor, but have large quantities of suspended food. This is something hard to replicate in a closed system.
IMO the easiest conditions that give reproducable results in large number of aquariums are; elevated Alk around (9dKH), low nitrate (1-2 ppm) and low but detectable levels of phosphate (~0.04 to 0.1 ppm).
Some of the most vivid coral colors are observed in ULNT that has undetectable levels of NO3 and PO4 and alkalinity around 7dKH. But these systems are very labor intensive, they require very close monitoring of parameters and almost always require dosage of some type of food source ( and some other stuff). Best example of this is the zeovit system. Keep in mind, in such systems if any parameter swings even a tiny bit, all corals can bleach in a matter of days. People using zeovit system even need to match the parameters (mainly alk)of the water the use for water changes to that of the tank water as even small swings resulting from that can cause rapid bleaching. Also in ULNS, unlike the parameters I listed above case, every tank behaves differently, conditions that work for one tank might not work for the other. And even the changes in "stuff" aside from water chemistry can cause bleaching, like if you change the bulbs of the T5 fixture, it can cause bleaching.
2- No, as long as your Mg dont go down. If Mg goes down, it can precipitate as Calcium carbonate.
3- Yes, same answer with 2.
