correlation between high ca and low alk

[dadonoflaw]

my ca is 640 and my alk is at 4.4dkh. i have to dose about 21/2 cups of the alk part annd nothing of the ca as of late until it comes down. the low alk also makes my ph fluctuate alot mostly on the low side. i dont know what to do.

[bertoni]

Are you using Oceanic salt? That's a common source of this problem. If not, some water changes might help. Otherwise, you'll just have to keep dosing alkalinity.

[dadonoflaw]

i am using reef crystals and when i do water changes it keeps the ca high. i have done several recently with little change. it has precipitated a bit and its still high. do you think that is why my alk is so low. because of high ca? also magnesium is 1500 so thats not it.

[bertoni]

I don't know how the alkalinity got that low. This calculator will help with dosing:

http://home.comcast.net/~jdieck1/chem_calc3.html

I'd dissolve some baking soda in water and dose that.

[dadonoflaw]

so you think i should stop baking it? i have been using the calculator to dose it now and i got a measuring cup to make sure its the right amount but my ca is staying high and my alk is staying low

[bertoni]

The problem with baking it is that causes a much higher pH. For that big a change, I'd just use plain baking soda. The baked version is fine for daily additions if the tank's pH is a bit low.