Alk question

S

satyra

I have a question about alkalinity in one of my tanks. I've been fighting with it for about 2 mo now, maybe slightly longer. It has been trying to stay at 6-7dkh. I tried 2 different alk supplements and doing lots of frequent partial water changes to bring it up, which did not raise the alk and keep it steady. Instead it seems to have raised my calcium even though I don't add calcium to the tank or the wc/top off water. So I finally tried adding some arm & hammer to my top off ro water, I raised it to 8.5 dkh before adding it to my tank. It worked perfectly! Now my tank is right at 8.5dkh and it has held steady so far.

so my question is, should I add the arm & hammer to my ro top off water every time I top off to keep it steady, or will it drive up my alk in my tank even if I match the alk in my top off water to the alk in the tank? I don't want it to swing around while I work on the issue...My goal is to have the alk around 9-10dkh but I'll be bringing it up very gradually.
 
Are you cooking the baking soda or just adding it out of the box? I have always baked mine at low heat for half an hour. Do you know what your magnesium is at, low mag can cause issues like this.
 
Are you cooking the baking soda or just adding it out of the box? I have always baked mine at low heat for half an hour. Do you know what your magnesium is at, low mag can cause issues like this.
 
Yeah I would start with posting a full set of tank params especially Mg, Ca, and Alk.

Also test the RO water that you are adding (after it is filtered of course) to make sure you aren't introducing anything counterproductive.
 
mg - 1400
Ca - off the chart, 31 drops using the api test
Alk was 6-7kh, now its at 8.5
Ph - 8.1
Sg - 1.026
Am, ni, na, phos - undetectable
Also recently bought copper and iodine test...copper is 0, iodine was .09

what tests should I run on my ro water? These are the only things I have tested my ro for:

Nitrate -0
Phos - 0
Am - 0
Kh - 0, I added one drop of the kh test and it was yellow already

I read that low mg could cause the alk and ca to go out of whack, but since its a little on the high end, I'm puzzled. I'm also not sure why my ca would be so high and only get higher...there are corals in this tank that all seem to be doing fine, see alot of growth in most of them. the only ones that took a hit were my sps frags which lost some color and the growth slowed down when the alk went down, they're still alive and I think they will be fine if my alk can stay high enough. One of my unidentified sps frags is acting like all is good though, its growing a lot still.

I've read mixed thoughts on getting the ca to come back down...some say to get more sps, get a clam...or something else that eats up lots of ca. Some say do wc's, some say do nothing.
 
Phone didn't let me post this all in one post.....

I did not heat up the water with the arm & hammer, I've never heard of doing that before. Is it necessary to do that? What are the exact directions for that procedure?
 
It's not the water you heat up...its the actual powder- cooking baking soda drives out the part that raises pH allowing you to raise the Alk without raising the pH. It shouldn't affect your Ca at all. Adding cooked baking soda should raise the levels of Alk and nothing else.
 
Ahhh ok. How much does it raise the ph typically? Before I used the baking soda my ph was 8.0, now its 8.1. I'm assuming it will raise the ph every time I use it, if I don't bake it? Could I just bake the whole box of it or is that something that needs to be done each time I need to add water?
 
You can bake a sheet pan at a time. Spread it out and cook it for half an hour or so. I have never done it so I don't know off hand. Im sure you can google it or search for more in the threads.
 
Baking it will raise the ph a lot. I have done it, dosed it in my sump and ph went real high but only in the sump for a few seconds. So it was all good. I've also used it w/o baking it and ph did not change much


http://reefkeeping.com/issues/2006-02/rhf/index.php

You can browse thru articles on that site that will help a lot!
 
Thanks for the links, I bookmarked them on my phone. I need to learn this chemistry stuff....I'm not great at all with math though so it takes a while to sink in. I'm just glad the corals and fish look happy and eat well. I'll try baking the baking soda next time and see if the ph shifts alot, if any.
 
I only have the api high range test kit for the sw tanks right now. I want the cool digital one, not sure when I can buy one of those.
 
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