As far as I know from my readings... Mg is only a trace element that corals use BUT Mg in its element form allows for higher levels Alk/Cal without issues such as cloudiness, precipitation etc. Therefor, a higher MG allows for more Alk and Calcium to be suspended in the water column allowing corals easier access to it when needed.
1mag test kit=25-29$ that's why I don't test that and just don't think I need to. Again I only pay attention to ca/alk/ph. It works for me
ok i must be missing something..if mg drops alk and ca will start to swing..then sps is going to be very unhappy..i will gladly pay 30 for a kit to keep my corals happy if thats what it takes. my alk stays around 9 which im not sure why because the last time i had it tested it was below 1000 ppm, so reasonably my alk and ca should be swinging.
I test primarily for alk. I dose mag through my calcium reactor with zeomag media and do water changes with Reef Crystals which is fairly high in magnesium. I do test for mag occasionally but I rely primarily on observing my corals. If things are growing well and maintaining color then parameters are in check. I am using a calcium RX therefore my dosing is continuous. If I were hand dosing I would test much more frequently.
It is true that low mag will make it difficult to balance alk and calcium. However this would be noticeable with levels much below that of natural seawater. You may not see major swings at the level you are at but getting up to around 1250 would give you a little more cushion.
Alk seems to me to be the fastest to deplete. Corals can take up carbonate very quickly especially as they get larger. Many people find SPS frags very easy to keep. They are often lulled into a false sense of security when they put a few frags in their tanks and all goes well. The trick is keeping things stable when you have a large population of growing colonies. Consumption rates can be enormous. This is where nutrients can be a big factor. Especially phosphate. Being that PO4 inhibits calcification a slight increase can slow coral growth and therefore consumption. The result can be a fairly sudden rise in alkalinity. Then when the excess PO4 is removed coral growth increases and carbonate (alk) drops. This is just one scenario to demonstrate why consistent husbandry and close observation are important in keeping these delicate corals. In a lot of cases SPS corals don't warn you they are unhappy. They just die and very quickly. Any number of changes in your routine can cause detrimental changes. That is why so few truly grown out SPS tanks exist relevant to other types of tanks. It takes years of consistent husbandry, no equipment failures, and a bit of luck. However IMHO grown out SPS tanks are the most beautiful of aquariums.
Originally Posted by whitetiger61
ok i must be missing something..if mg drops alk and ca will start to swing..then sps is going to be very unhappy..i will gladly pay 30 for a kit to keep my corals happy if thats what it takes. my alk stays around 9 which im not sure why because the last time i had it tested it was below 1000 ppm, so reasonably my alk and ca should be swinging.
thanks Andy for the great write up..so far everything is good..and i do think the test that was taken on my tank was wrong..i could have picked up a contaminated test vile when marc did the test..might bring a sample in to you and have you test it..i would at least like to know where my base is..
Originally Posted by CableGuy
that and just don't think I need to. Again I only pay attention to ca/alk/ph. It works for me
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