Question about using two part solution and Mg suppliment.

[Radioheadx14]

I have a 34g Solana cube mixed reef
Right now my parameters are:
kH 8 (API)
Ca 380 (API)
Mg 1000 (ELOS)

My kH is in good shape but my Ca and Mg are a little low. I have ESV B-Ionic 2 part and ESV Bionic Mg. I used the "Reef Chemistry Calculator" and it said I should add 70mL of calcium, 4mL of kH and 850mL (!!!) of Mg to get to:
kH 8.3 (API only tests to the nearest number... I have a salifert kH test but its one of the bad ones)
Ca 420ppm
Mg 1300ppm

Is this reasonable? The bottle says to add the 2 part in equal quantities. and that Mg amount suggested is almost the entire bottle. I know all of the levels influence each other and I have read several of the suggested articles, but its still unclear how the whole things work... I took the intro Chemistry series in College like 2 or 3 years ago so I'm a little rusty.

I use reef crystals, I tested it, when I bought the bucket, to make sure it was a good batch. Ca was 380-400 and Mg was 1100-1200. I also did a pretty big water change on Saturday and rescaped my rocks.

[bertoni]

Assuming there's 20g of actual water in the tank, I get about 600 ml to get the Mg in line. That amount sounds reasonable. I'd try 100 ml, and see how that goes, and then try raising Mg no more than 100 ppm per day.

Since this is a one-time adjustment, adding just the calcium part is fine, if the alkalinity level is where you want it.

[Radioheadx14]

I added 17ml of Ca solution and 100ml Mg. I'll check everything again tomorrow.