Raising mg
 

MG: 1250
CA: 420
KH: 7

Bringing up mg. just want to know how fast I can raise it. I'm using. Seachem advantage mag. It says 50mg a day which I'm doing, but never really trust a sticker.

50g. Per day 45g total tank volume

try one or two of the "reef chemistry calculators" to see if they have the product you are using listed.....they will tell ya the recommended amount to bring your Mg level up....

I'm using seachem a calc. Doesn't suggest a daily limit. I'm almost at target. Just don't want to over do it.

The BRS calculator suggests not raising any more than 100 ppm per day. I wouldn't think it would make any difference what product you used to accomplish that.
HAve you tried using this link:
http://www.seachem.com/Library/Calculators.html
Click on the reef version, choose your additive, plug your numbers in and it will tell you exactly how much you need to add for that specific water volume.
I use the BRS one for their additives and it's spot on, love it.

your magnesium is not far from the target, so I would not worry about it.

Some people use Kent magnesium and raise it to 1600 suddenly without any ill effect except on the bryopsis :)

I actually use their app. It's great.

Seems like its been hard raising mg. been dosing since Friday to bring up 50 ppm a day. Ill just bring it up and monitor loss.

Does mg get absorbed into rock at all as other params are spot on

Not sure if this has been other people's experience, but I did find that when I started dosing Mg, it did take a fair bit to bring it up. But once it was up where I wanted it, it was pretty easy to keep it there.
Once you get your levels where you want them, don't dose for 24 hrs, test again and use that as your start for maintenance dosing.

I try to target a max of 20ppm per day of increase when I have to do it. However, I just like keeping things a little steady in my system...lol

Quite surprised how much it took to raise. About half of a 1.2kg tub. Lol

I'm at 1360 now and will test around 4 pm to see what loss is in 24 hours.
No sure it its related to low mg but my terria del fugo lost some tissue. Should be ok as I still have PE