Newb at chemistry - Kh, Calc, Mag questions

I can keep my mag around 1300 and my calc at 42-450 no problem. My alk however is always around 8 when I water change, and then a week later around 7 or maybe 6 if I wait a couple weeks. Also, my ph almost never changes at 8.3. What can I do to just raise my Kh up? I know some thing regulate Ph, or mag or calc, I just want my alk up about 3-4 notches.

I see do it yourself with baking soda but doesn't that affect ph?

Sorry for my ignorance, I read the searches and can't make anything out lol

 

Baking soda might bring your pH down to 8.1 at the worst. That is well within acceptable range. You definitely will need to add alkalinity to keep your dKH up. You may also find that you will need to supplement Ca and Mg due to interaction between the three and increased growth among your corals.

 

So using baking soda, is there a unit I should start with? teaspoon per gallon or...

 

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k3rack

check out the calculator as that will tell you how much of any given product, including baking soda you need to increase levels

general rule with DKH is - do not increase by more than 1 degree in any 24 hour period
a target of 8 and maintained at 8 is perfectly acceptable IME - you want to avoid it dropping below 7 especially with sensitive corals

mix it with rodi and set it up in a bottle with clamped airline and regulate it so you get 2 or less drips per second

Steve

 

Is this something I should be performing once a month or do you think my alk will be deteriorating quicker?

I do 20% weekly in which it's at about 7dKH, 9 after the change. If I jump it up to around 3 points shouldn't it be consistently that much over if I keep to my schedule?

I'm not good with this part of the water chemistry obviously, thanks for any help :|

 

K3rack

if your DKH is dropping from 9 to 7 during the week
you are losing 2 degrees in 7 days and thats just over 0.25 DKH per day

which is exactly the current demand on my tank as it happens

what you need to do, is double check your Calcium level

with every 1 degree of DKH utilised there is approx 20ppm Calcium utilised
(I say approx, because Magnesium and Strontium could also being utilised so you might not see a perfect 20 ppm Calcium and 1 DKH drop every time)

it may be that some of your DKH is going towards maintaining your tanks PH thus again this does interfere with that 20 Ca and 1 DKH drop
but its worth double checking

if it where me after just making sure it was not just DKH in isolation dropping

I would look at dosing to replace the 0.25 DKH on a daily/ nightly basis
so that its at 9 after the water change and then stays at 9 until the following weeks water change

that will give you stability (sure 7 - 11 are within tolerance for a reef tank but you dont want to fluctuate to much between the 2 numbers)

pick a number - and 9 is fine and then select a buffer/ carbonate product that enables you to maintain that level on a daily basis

check out the 3 reef calculator for ideas on what type product you can choose between for helping maintain the levels

Steve