dKH ???

[StephenA]

I know this subject has been asked to death.

I can't seem to keep my dKH up in my new tank. It stays around 5-6 no matter what I do. pH is 8.0 to 8.3, CA is 470.

I use Kent Superbuffer for the dKH, and I drip kalk about every other night. I keep my new saltwater mix at 10, but my dKH is always around 5-6. What am I doing wrong?

[matt]

First, I'd make sure your test kit is accurate. Once you've determined that, try using plain baking soda as a carbonate supplement. It'll boost your alkalinity without spiking your ph. BTW, 470 is a little high for calcium; not a problem by itself, but you might find when you raise your alkalinity that your calcium drops a bit. Right now you're a little off balance. I assume you're using KW only to boost your Ca? If that's the case, I'm not sure why you got out of balance. Did you also add some calcium chloride, like Turbo Calcium? If not, maybe your calcium test isn't quite right also. I'd get a Salifert test kit for both Ca and Alk (assuming that's not what you're using now) and take your readings at the same time, maybe both in the morning before the lights come on, then again in the late afternoon.

NSW levels are about 400Ca and 7dkh. Most people boost the alkalinity to about 9-10, because in most systems that's what gets depleted the quickest. As long as it's stable and you have no ph problems, there's nothing wrong with keeping it at a steady 7 or so. Oh yeah, just to make sure, your reading of 5-6 is dkh, not meq, correct? Probably you're aware of this, but I had to put it in to make sure. 5-6 meq is on the high side and would be more in line with Ca 470 using KW.

[StephenA]

I only add KW to boost CA, I use Salifert Test kits. I'll test the dKH with my Tetra kit this morn. And I do go by dKH, not meq/L

I'll run all the test again with the same kits and different kits. Thanks for the help Matt!

[matt]

If you're pretty confident your readings are accurate, try the baking soda. It'll work.

[StephenA]

Tetra dKH = 10 New Kit
Salifert dKH = 11 6mo Old Kit
pH = 8.3
CA = 420

I added superbuffer last night, and did NOT drip KW.

[ratboy]

You might want to check your Mg. Magnesium plays an important role in Ca/Alkalinity so if your Mg is too low your Ca cant be utilized by corals.

[mharris7]

kalk will help your alk as well as calcium - the hydroxide ions in it mix with CO2 in the system to create carbonate alkalinity.

[R.Allard]

sea chem reefbuilder does the same thing and has some added trace elements like mg,strontium and potassium.

[matt]

Now, 420Ca and 11dkh is much better balanced, PLENTY of carbonate. I'd add nothing for a day or two and check again. See what's getting depleted more quickly.

[StephenA]

MG=1420 ppm
pH=8.2
dKH=10
CA=410

It figures I start asking questions and the tank stablizes!

[COBRA201]

baking soda is chep and works great.. :-D i always have problems with alk so i use it to pick it up, might be because of my calcium been at 500-600 :lol:

[GaryP]

Baking Soda will raise Alk, but not pH. To make a good buffer that will do both, use a 6:1 ratio of baking soda to washing soda (Arm & Hammer Super Baking soda). It is available in most HEB's on the aisle with the laundry detergent. Chemically it is sodium carbonate. This mixture is basically what you are buying when get any of the commercial aquarium solid buffers. Add some high priced water and you have the A part of a two part additive.

Gary

[StephenA]

Do you just use them plain, no prep?

[GaryP]

Stephen,

Check out this thread. I posted it yesterday to answer some questions on my 2 part system. It has a description of how I make up the buffer and apply it. Let me know if you have any questions.

http://maast.org/index.php?name=PNphpBB2&file=viewtopic&t=5232

Gary

[StephenA]

Thanks! any way to save money is always a plus.

[GaryP]

I can make up what would be a $30 bucket of Kent buffer for about $2.

Gary