R u guys testing for CA?  if so, what tests are you using? 
What's your calcium level? 
Do you dose? If so which product are you using?

I check mine maybe 2x a week. I am very particular about test kits, and after spending lots of $ on them, have chosen the top ones.
I like the brand Red Sea, it was the closest I have come across to the results yielded by a Salifert kit I had in the past. Obviously, no one wants to keep spending 45 bucks in test kits so I buy the red sea that can be pretty good as well and is around $18. The calcium usage is very inconsistent in my tank, and dosages are never the same. I have been able to keep it stable, and use Brightwell's Concentrated Calcion. I used to be a Seachem guy, but after trying Brightwell's products, mainly alk buffers and calcion, I noticed they not only are way stronger(+concentrated) but also come in larger bottles lasting longer.
I have been keeping my Ca around 460ppm.
I also have been keeping my alk at 4.5meq/l. These two have been giving me coraline like never before... All equipment in sump and tank have gotten covered in matter of days at those levels.

Babyreef,

When I was using seachem's "in vitro" line of products, which seemed to be their best stuff, I was going through liquid alk buffer bottles like crazy. My tank could never get to above 3.2meq/l with liquid buffers and I was already adding something like 75ml per day. The bottle was 400ml so go figure! Calcium not as much but a lot also. I switched to Alkalin liquid by Brightwell and I liked it because I was dosing way less, and could keep my alk at around 3.5. I tried then Brightwell's powder version, Alkalin 8.3-P and was amazed! I dissolve 3 teaspoons in 8oz of fresh water and my alk stays at 4.0-4.5 for 2-3 days. The package comes in 500g and costs a lot cheaper than the liquid form. One box should last 2-3 months. The calcion is a concentrated calcium liquid(150000ppm) and I only add 2-3 caps(5ml each) maybe 2x a week and my cacium stays at around 450.

Babyreef,

I used to test weekly my Mg and almost every time came with it being over 1300.
I even have a brand new bottle of Seachem's "Ions" which is a Mg supplement, that i havent even opened since I never needed it.
You are correct, Mg has the ability to keep Ca and Alk stable without dropping too fast in the tank.
I have been dosing trace elements every week as well and I do water changes every other week which i believe has been enough to keep my Mg above 1200.
I really liked Seachem, but with all honesty, with Brightwell is so much easier.
The dosing is just as easy, the directions are easy to understand.
I was spending in supplements monthly:
7 bottles of alk(seachem) @ $10 each= $70
1 bottle of Calcion(brightwell) =$14
1 Bottle of TLF Phosban Media=$18
1 bag of Chemipure carbon=$15
total: $117!!!

It was obvious alk buffers were out of control. I did research and noticed many people had similar usage per day... around 50-70ml
So the only way was to find a more concentrated product. I searched for BRS(Bulk Reef Supply), but a friend has their alk buffer and it is weak too. The bottle is also small.
I tried Kent's alk buffer and it was the worst of all of them. Fresh water from my sink would have maybe helped more.
So while at the LFS i looked for other reliable sources, and Brightwell was one that caught my eye.
I started adding the liquid that comes in a 500ml bottle and found that the concentration was greater than all the others, but the dosage was still high. not as high as Seachem's but high too.
I started ordering the 2litre bottles to avoid me having to go by the store every week.
One day they had not gotten the order in for my 2l bottle so I had no choice but to grab their powder form.
Best thing ever!!
Now like mentioned before i have a package of powder that lasts 2 months at least, and is much better. Dont fall in the hype "dont mix Seachem's products with Brightwell's or others"...thats marketing so you only buy their products.
I mentioned Calcion is also my choice from Brightwell because if you check on the concentration of all competition, it is not as high as calcion's 150000ppm.
My monthly cost now with the powder:
Alkalin 8.3-P $14
Calcion $14
1 Bottle of TLF Phosban Media=$18
Carbon: do not use anymore, no bad, no good(water is clearer but not worth the hassle of another thing to worry about!
totals:$46.......

Thanks for the reply, I have the Brightwell products on my shopping list for my next visit to LFS superstore a couple hours away. I make the trip once a month and stock up on supplies I need. There prices are quite good. They carry the entire Brightwell line, including the potassium I am looking for and Alkalin 8.3-P, Calcion-P. I still have some Seachem products to use up here first but only a couple of weeks at most. Keep you posted.

Brightwell Aquatics Alkalin8.3 Powder Aquarium Buffer - 500 Gram              $9.65   


Brightwell Aquatics Calcion-P Powder Calcium Supplement - 800 Gram     $17.55   

Brightwell Aquatics Potassion Liquid Potassium Additive - 500ml                     $10.55

Brightwell Aquatics Magnesion-P Dry Aquarium Additive - 600 Gram             $13.30