Lowering Alk

MACH5 · #1 12/29/2007, 03:44 PM

Hello.
I would like to ask what would be the best way to lower my Alk on my newly mixed salt water. I just tested it and it's 12dkh. Need to bring it down to about 8 or so.

Thanks

Percula9 · #2 12/29/2007, 06:22 PM

12dkh is still within normal range, it's the upper limit. Stop dosing buffer until alk goes down. Alk of 9-10 is a good range.

bertoni · #3 12/29/2007, 08:15 PM

What brand of salt is being used? How is SG being tested, and how was the device calibrated?

MACH5 · #4 12/29/2007, 10:24 PM

Tropic Marin Pro. Refractometer calibrated with RO.

bertoni · #5 12/29/2007, 11:20 PM

I'd try calibrating with some of the PinPoint 53 mS solution. Calibration with RO/DI water can be very inaccurate:

http://reefkeeping.com/issues/2006-12/rhf/index.php

I think that result might be reasonable for that salt product, though. I'm not sure.

MACH5 · #6 12/30/2007, 12:05 AM

Ok thanks bertoni... will do. I'm just trying to lower a bit my Alk. My tank runs about 8-9 dkh. My newly mixed water reads 12... so just want it to bring it closer.
I've read about using sparkling water to lower your Alk and so I tried it. But it seems that you need to dose quite a bit of it to bring it down. I put one liter into about 40 gal. of salt water and the Alk still about the same.

bertoni · #7 12/30/2007, 12:44 AM

Sparkling water won't lower the alkalinity. It just reduces pH temporarily. A mineral acid can lower the alkalinity, but they are a bit dangerous.

MCsaxmaster · #8 12/30/2007, 03:31 AM

Agreed, just stop dosing whatever you're dosing for alkalinity and wait a couple of days. It should drop on its own due to calcification.

Billybeau1 · #9 12/30/2007, 04:12 AM

Many salt mixes like IO, RC and others make their salt mix that high on purpose.

Let's say your tank is at 9 dkh. You do a 25 % water change with a mix containing 12 dkh.

You will see very little difference in the rise in dkh in the main tank.

Conversely, if your tanks dkh is 9 and you keep doing water changes with water that is 9, you will continually have to add an alkalinity supplement to maintain your levels.

Instant Ocean @ 1.0264 runs about 12-13 dkh and no one seems to be having any problems with high alkalinity.

MACH5 · #10 12/30/2007, 08:58 AM

Ok. Thank you all for your comments. Very helpful!

Billybeau1: It looks like I may be worrying too much. I agree, I guess a partial water change would not cause a significant rise in my Alk. At least not enough to stress the animals.

Thank you all

Billybeau1 · #11 12/30/2007, 12:38 PM