View Full Version : How to quickly lower alkalinity?

10/27/2006, 05:31 AM
My alk was testing 6 KH, so I added a bit of baking soda for now, figuring I could adjust it percisley after work. Well it turns out I raised it to 20 KH:eek2:

The Tropic Marin booklet suggests 7-12 KH range. Is it crucial I lower it before work, and if so, how?

10/27/2006, 06:01 AM
Wow dws, I have never seen anyone have a alk that high. Are you sure? Try the test again. If it is that high do a mega water change and do it right now! Try to get the alk down to at least 15dkh or so before you go to work. Hope you are not late to work, but we all know that are reefs come first.


10/27/2006, 06:30 AM
If a bit of baking soda is around 30 teaspoons, then you could raise from 6-20 on a 46 but I'm guessing there is some testing error present.

10/27/2006, 07:42 AM
Well testing dKH is just counting drops before green changes to orange. 30 teaspoons, that's possible. I used about a third of a standard small baing soda box. Major 6:30 am brain burp.

I searched and found Randy mention calcium, so I added 3 tablespooons before I left.

Everything in the tank actually looked better a 20 dKH than at 6, I left the actinics on and the slime algae did not re-appear like it normally does within minutes.

10/27/2006, 07:45 AM
You could do a water change but personally I'd just let it drop on it's own. Provided you have normal magnesium levels it shouldn't be a problem. If your mag is low it may cloud with a precipitate but deal with that if it happens. To correct that just fix the mag, then ca and alk. You will probably drop .5 to 2+ dKh per day depending on your tank.

Randy Holmes-Farley
10/27/2006, 11:13 AM
I too would just wait. it will drop on its own. If necessary, add calcium chloride to maintain calcium over the next few days.

This article has more:

Solving Calcium and Alkalinity Problems

and this calculator shows how much calcium chloride or future additions of baking soda to use:

Reef chemicals calculator

10/28/2006, 02:55 PM
I too have been suffering from abnormally high Alk.
I am using a Salifert (newly purchased) test kit and am reading 5.6 meq/L. I have tested several times with the same result over a period of one week.
My PH is 8.3, Ca 430ppm and Mg is 1350.
I also have a Red Sea kit and will test with it for comparison.
My concern here is that I recently lost 2 fish to crypt, treated with Kick -Ich, which I believe has gotten rid of the crypt. It has been 2+ weeks since the outbreak and fish loss. My corals started looking poorly the last few days so I have done a 30% water change and would like to see the Alk lower. No clacification visible at this point.

Any suggestions would be greatly appreciated.

Thank you,

Randy Holmes-Farley
10/28/2006, 03:08 PM
5.6 meq/L is not likely causing fish diseases, IMO, nor do I think it will cause most corals to do poorly. Many folks have alkalinity that high without such issues. I'd look for other answers.

Do you know how it got that high? Are you using tap water?

Water changes are not usually a useful way to drop alkalinity, unless it is really, really high. At these levels, I'd just let it drop on its own.

10/28/2006, 10:07 PM
Wait I did, and drop it did. As of tonight dKH was at 11. Almost quick enough to make me worry.

10/29/2006, 05:18 AM
Yes for the time being I have been using tap water. My corals were looking quite good after the LFS came to visit, aquascaped my tank and cleaned it while doing a water change with RO/DI water.
I suspect I need to head in that direction and have started looking into a unit.
The disease was brought to the tank via a new hippo tang.
Yes I also need a quarantine tank. I have a 29 gal I am going to setup right away for that purpose.
Would you suggest stopping the dosing of B-Ionic until the Alk drops? The Ca seems to hold consistent without the treatment for that last 3 or 4 days.

Thanks for the input,

10/29/2006, 07:08 AM
<a href=showthread.php?s=&postid=8435696#post8435696 target=_blank>Originally posted</a> by DWS
Wait I did, and drop it did. As of tonight dKH was at 11. Almost quick enough to make me worry.

Thats quite a drop-- check your calcium-- if it dropped too you may have had a precipitation event (calcium carbonate solid formation)... in which case you may need to bump your calcium back up

@ bj

If you mean adding just the calcium half of a 2 part while waiting for you alkalinity to drop then yes thats fine... you should not have to add your alkalinity half for a while-- really depends on your tanks consumption how fast it will drop....

Randy Holmes-Farley
10/29/2006, 08:08 AM
A 10 dKH drop in alkalinity will be accompanied by roughly a 70 ppm drop in calcium, so as Bill as suggests, check that. :)

Would you suggest stopping the dosing of B-Ionic until the Alk drops? The Ca seems to hold consistent without the treatment for that last 3 or 4 days.

That's normal, and stopping both parts for a couple of days ought to do the trick. :)

10/29/2006, 09:01 PM
thanks for the advice. I will monitor both closely and probably add CA part of the B-ionic while watching the alk
Thank you again

Randy Holmes-Farley
10/30/2006, 06:43 AM

Good luck. :)