A couple of thoughts to share.... This is what I did.
Starting off testing and dosing can be daunting. I'd suggest reading as much as you can and testing your tank daily for a good month to really understand what is happening with your levels. It is a lot of work up front, but in the end it can pay off wonderfully. Here is why.
What you want to do is understand how much your tank is changing daily, even before and after water changes. This will allow you to know how much and how often you will need to dose in order to maintain levels of Ca, Alk, and Mg (before, after, and during water changes). Maintaining stable parameters is what you are aiming to do here. Don't chase numbers. Note: this is testing w/o dosing anything b/c you want to get an idea of how much your corals are taking in.
Yes, daily testing b/c when you do start to dose you will be setting up your doser to deliver Ca & Alk daily. As for Mg, depending on how much is being utilized in your tank you may only need to dose once or maybe twice a week at first.
While you are testing daily. Also test your newly mixed salt water. You want to have a good idea of the Ca, Alk, and Mg of your fresh mixed saltwater has in it. Don't just go with the label on the bucket b/c the amount of these can vary a bit. You will also find differences with the salinity levels. By testing the newly mixed salt water you can try to maintain the tank levels to the newly made salt water levels so that when you do water changes you won't see any fluctuations in the tank.
Again, don't chase numbers. The numbers can vary a little bit without issues.
After a while you don't need to test the newly mixed salt water. I know test every new bucket I get, just so I have an idea what the levels are. After this first month and once you start dosing, you may only want to test every couple of days. Test to make sure your dosing amt is correct so you can adjust accordingly.
After the first month or so, once you feel good about your dosing amounts and levels, you may only need to test once a week. Then test once a month. After that you will probably do what all of us do, stop testing b/c it is too much work
. This isn't necessarily good for our tanks. But, it happens. I now only test when my corals aren't looking happy - not good advice, but it happens.
This thread was helpful to me, you will want to scroll down the page a bit:
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