Jump to content

kH Supplements


Recommended Posts

I've noticed a slight decrease in my kH (Carbonate Hardness). I do not currently supplement it, however I do supplement calcium and magnesium. Should I also be adding a kH buffer? If so, what should I get? What comes highly recommended? If I purchase it, how should I apply it, and how often?



Link to comment
Share on other sites

Yes, seawater is a balance of ions.

And for a given volume of water, it has a saturation limit.

So - it stands to reason that if you raise one ion - (Calcium) in the water -others will fall (Carbonates).

There are many others but these 2 counter-balance each other, as well as play the most important role of

being the 2 halves of the Calcium Carbonate skeleton of most stony corals.

Anytime you add one then the other is almost certain to fall, as the solution must remain chemically balanced to be stable.

There is a trick - keep the Magnesium at NSW (Natural Sea Water) levels.- Dont let it fall, and it will act as a catalyst

which will allow you to raise both Calcium and KH to NSW levels without tripping major swings in either one.

(It will still swing "some" - just not so badly as it would if the Mg is too low.. and if you "go slow" about changes you may not see a swing at all.)

Yes - there are commercial buffers available, and then there is what we've been using (Arm&Hammer baking soda).

I recommend employing both - until you decide which is best for your system.

Baking soda (bicarbonate of soda) may be employed, but be sure to

a.) bake it in a flat (clean) cookie sheet at 300 degrees for 30 minutes (it will get much lighter and powdery) and then

as soon as it cools a little, immediately store it in an air-tight container (big mason jar, mayo jar pickle jar, etc..) ,-glass container if possible

so it doesn't absorb any moisture/impurities from the air or the jar (don't use plastic or metal containers if possible) while it is stored.

Baking Soda is probably the worlds greatest "odor eater" and this is why - it will absorb anything it comes in contact with,

so it's important to store it air-tight in a totally inert container that can be cleaned to the level of sterility (like glass).

Until you master this method - try out Seachem's Marine Buffer. It has served us very well in the past. It just gets

expensive with a large tank if you don't have a reactor running.

Others may recommend even better ones. - These are just the ones Cindy and I have been using the last 5 yrs.

We switched to Baking Soda a few years ago to save some money - but now that we have a Ca reactor our total cost

of additives has dropped to where a Ca supplement we used to use up in a month now lasts us about 8 months.

And the Baking soda is so cheap - it's cost is practically zero.

now - dont guess at how much to add - use one of the many online reef calculators out there on the web where you

input your tank water volume, and your current parameters, and desired parameters, and your type of additive,

and it will tell you how much to add to reach your target level.

Hang on - let me find one of them to get you started:


We used this one, there are others. - read the info there as well about side effects, etc.

-research, and good luck :)


Link to comment
Share on other sites

I am baking the baking soda as we speak. It's the Arm and Hammer Sodium Bicarbonate (just in case there is another type). Apparently, if I want to keep my dkH at 12, I'll have to add 3.6 tbsp (over a drawn out period of time.) I currently use Seachem's Reef Complete. (Stronium, Calcium, and Magnesium supplement) and I dose it weekly. My current calcium level is 420 ppm, and I'm hoping to raise it to around 460 ppm over the next week or two.

How much do you recommend adding /day?

Link to comment
Share on other sites

Can't answer that last question, but will add this.

Don't supplement, what you don't/can't test for. I'm speaking to the Strontium specifically, although there are test kits for it(and you may be using them, in that case :) )

I have used Seachem stuff in the past and like it, but I would go with a 2 part supplement and a Mag supplement by itself. Most(all?) other elements needed should be supplied by water changes.

Link to comment
Share on other sites

If you are at 12 I would stop.

between 8 and 12 is good. Just don't go wild with it.

I would not raise it more than 1 degree KH/day.

so what does the KH reading test for now?

For instance if mine was reading 7 and I wanted to reach, say 10... then I would divide the amount to raise it by that much by 4

and do 1/4 of it per day (testing every day,and making minute adjustments to the plan as needed).

Just make changes slowly - that's very key. Or you risk total collapse (snowstorm). And you DON'T want a snowstorm.

(A reaction where everything drops out of the water at once) - and once it starts - there's NO stopping it either!

You can cause it by swinging either Ca or KH buffer TOO QUICKLY in either direction so be careful and go slow ("more is NOT better").

Link to comment
Share on other sites

Thanks for the part about baking soda. I had forgotten how to prepare it. You als use the calculator and pharmaceutical grade Epsom Salt (found at HEB) to supplement magnesium. But that is another story . . .

Link to comment
Share on other sites

I currently use Seachem's Reef Complete. (Stronium, Calcium, and Magnesium supplement) and I dose it weekly. My current calcium level is 420 ppm, and I'm hoping to raise it to around 460 ppm over the next week or two.

How much do you recommend adding /day?

Seachem's Reef Complete is all I dose in my 75g (i.e., no dKH). 3 capfuls should get you from 420 to 460. You can add 2-3 capfuls at once in a 75g with no issues. I tend to add it before I turn the lights on, but it's not a requirement.

I usually dose twice per week: once on Sundays when I do a 10g water change (add it right to the new water after dissolving salt) and another time mid-week. With the mixed reef I keep, this routine keeps my calcium between 420-450.

Link to comment
Share on other sites

That's what I'm using right now... I usually put a little in with my topoff jug. My calcium is currently 420 I believe..

Here we go...

My Parameters:

Calcium - 420 ppm

kH - 11 dkH

Ammonia - Untraceable

Phosphate - Untraceable

Nitrate - Untraceable

Nitrite - Untraceable

pH - 8.2

Salinity - 1.024

Temperature - 81

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Create New...