CA/ALK/PH and MG questions

fresh · #1 06-16-2006, 12:32 AM

Hi all,

I have been using the home-made 2 part CA and ALK system for a while now and have noticed lately that my ALK always drops faster than my CA!

In the span of a month, my CA went from 400 to 380 while my ALK went from 9.2 to 6.4.

I haven't started adding the third part to the equation and that is the magnesium sulfate.

I have already added the ALK once by itself without adding any CA hoping that would fix it, but it didn't.

The questions that I have are:
1- Is the CA drop normal for an average stocked sps/clams tank in 1 month?
2- Is the ALK drop normal for that tank in 1 month?
3- Is not adding the magnesium sulfate the reason for the ALK swing?
4- What can I do to balance out the equation and where am I going wrong?
5- How bad is ALK 6.4 to my corals? Do I need to panic?

I have a 72gal tank with low bio-load, 100+lbs of lr, 4" aragonite dsp, and a good skimmer.

I have a few good sized sps colonies, 2 large clams, a couple of large lps, and numerous frags of sps.

Thanks for taking the time to read, and I appreciate all the help I can get.

Fresh.

Denis · #2 06-16-2006, 02:58 AM

What's your Mg level ?
I'm surprised that your Alk drops so much with DSB.
Ca drop is somewhat large, hard to say.
The third part should actually be mag sulfate and mag chloride (2:3).
Alk swing like that are bad, you should dose more frequently (daily).
Alk 6.4 not a panic, but immediate action necessary.
My guess is that you Mg is low (~1000).
Aim for more stability, possibly invest in a dosing pump.
Hope this helps.

DanG · #3 06-16-2006, 03:53 AM

Your ca dropped from 400 to 380 in a month with sps colonies and clams?
What are you measuring with?

fresh · #4 06-16-2006, 04:12 PM

salifert test kits. I was told those are the best in the market!!!

So Denis, you are recommending that the swing is due to the magnesium sulfate, is that correct?

Denis · #5 06-16-2006, 04:18 PM

not sulfate, just magnesium,
Do you have a testkit for Mg ?
I also use Salifert.

fresh · #6 06-16-2006, 04:53 PM

Well, according to the 2 part home made additive, the 3rd part to balnce out the magnesium in the system is epsom salts and that is magnesium sulphate!!!

Denis · #7 06-16-2006, 05:06 PM

Yes, that's the old method that leads to buildup of sulfate.
Look at this new one : http://reefkeeping.com/issues/2006-02/rhf/index.php

I'm still looking for that MgCl , food grade is too expensive (5kg @ $95.40).
Any one knows where to get Mag Flakes (by DOW) ?

DanG · #8 06-16-2006, 05:19 PM

Quote:

Originally Posted by Denis

Yes, that's the old method that leads to buildup of sulfate.
Look at this new one : http://reefkeeping.com/issues/2006-02/rhf/index.php

I'm still looking for that MgCl , food grade is too expensive (5kg @ $95.40).
Any one knows where to get Mag Flakes (by DOW) ?

http://www.canreef.com/vbulletin/showthread.php?t=25122