Maintaining Alkalinity levels

[neilanh]

ugh - frustrated

A while back I realized my bioload was getting up to where I was seeing really low Calcium levels. Sparky convinced me it was time to start dosing 2-part. Been doing it slowly over the past month or so.

My issue is my Alk. My Alk has always been on the low side ever since my cycle completed. Initially it was up around 10 when I first setup the tank. Afer the cycle completed it dropped and held around 8. about 2 months ago it hit 7, and that's where it's been since, even since I started dosing. Tested with both API and IO test kits. Oh, all Alk readings in dKh.

I dose 2-part. I put in enough part B to raise the Alk by 1, and by the next day it's back down to 7 again. What's causing it to fall?

Tank Params:
temp 81
basics are all 0
Sg 1.025
pH 8.0-8.1
Alk 7dKh
Ca 400ppm (I know, still a bit low, not rushing it up)
Mag 1280

Other things you might need to ask me:
Reef Crystals salt
Aragamax sand
Do run GFO and Carbon
25% water change every other week

[HN1]

Have you thought about adding a reactor? I think that would take care of both the alk and calc concerns. Could be totally wrong though. That's always a possibility. lol

[Innovator]

Do you have any corals in the tank? If so, how long has it been up and running with corals?

Edit: Well since you logged off I will go ahead and answer anyways. Alkalinity is much more "sensitive" than that of calcium and often fluctuates at a faster rate. Many of your calcifying organisms utilize calcium carbonate and bicarbonate for skeletal growth thus quickly depleting; however, this does not mean the system is imbalanced and rather you just need a higher level of supplementation (Calcium and Alkalinity) to achieve a higher balance. Note that water changes, top-offs, and nitrogen can alter the balance.The reason you see an overnight reduction in Alk is because seawater normally contains calcium in abundance to that of Alk so in order to make an impact a higher dosage is required. Raising your Mag will also help and altogether help stabilize a higher pH.

[Kurt_Nelson]

Have you tried one of the "new" buckets of Reef Crystals? I'd originally thought it was just new packaging, but it does appear that they've tweaked their numbers a bit with the alkalinity coming in several degrees higher than it used to... like around 12+ dKh.

[SparKy697]

Originally Posted by Kurt_Nelson

Have you tried one of the "new" buckets of Reef Crystals? I'd originally thought it was just new packaging, but it does appear that they've tweaked their numbers a bit with the alkalinity coming in several degrees higher than it used to... like around 12+ dKh.

That's interesting because I have noticed exactly that as well as an increase in mag.

[neilanh]

Sorry, I guess I just always assume people are familiar with my build thread.

Yes, corals galore, all shapes, sizes and colors.

I guess I expect the calcium to get depleted, and can understand why I have to dose it pretty heavily, I just didnt know Alkalinity could deplete too. And I sure feel like I'm dosing heavily on it already, and all the cautions that come with it obviously have me running a little scared.

I'm using the BRS 2-part dosing kit. They recommend .4-.6ml per gallon for a daily dosage. I'm currently dosing 70ml per day into my roughly 80g water system. Has me nervous.

I thought Alk, like Mag, would build up as I dosed and then just need a little bit of a maintenance dose. Not that it would need a heavy daily dose to hold up. Well, I say hold up, even though I can't even seem to really get it to move upwards at all really.

[neilanh]

I'm on my 2d bucket of the "new" buckets. Didn't realize they tweaked anything, but yes that's what I'm using.

[Kurt_Nelson]

Originally Posted by neilanh

...
I guess I expect the calcium to get depleted, and can understand why I have to dose it pretty heavily, I just didnt know Alkalinity could deplete too. ...

Both calcium and carbonate (the alkalinity part) get depleted at the same ratio. That's the beauty of the 2-part system... once you figure out what your daily ca requirements are and get your ca/alk balanced, you just dose the same of each, each day.

I'm currently dosing 70ml per day into my roughly 80g water system. Has me nervous.

You're right. That's a lot.

I thought Alk, like Mag, would build up as I dosed and then just need a little bit of a maintenance dose. Not that it would need a heavy daily dose to hold up. Well, I say hold up, even though I can't even seem to really get it to move upwards at all really.

Maybe I'm not reading this correctly, but 2-parts are meant to maintain your ca/alk levels where you want them - once you get them to your target values. Small daily additions that correspond to how much calcium your tank sucks up per day is all you want to add. To get your calcium levels up to where you want, use something like TurboCalcium or the like.

[Kurt_Nelson]

Originally Posted by SparKy697

That's interesting because I have noticed exactly that as well as an increase in mag.

Yup. Magnesium and calcium have also been bumped up. I didn't think it had until I tested one of my new buckets. In chatting up someone on another forum, he also confirmed it'd been changed and his source was someone from within the manufacturing side of Reef Crystals.

[Innovator]

Originally Posted by Kurt_Nelson

Have you tried one of the "new" buckets of Reef Crystals? I'd originally thought it was just new packaging, but it does appear that they've tweaked their numbers a bit with the alkalinity coming in several degrees higher than it used to... like around 12+ dKh.

Originally Posted by SparKy697

That's interesting because I have noticed exactly that as well as an increase in mag.

All salts have inconsistencies, which is why you will notice certain elements raised or decreased over time. From what I have heard, areas of elemental acquisition and processing are the main causes for concern with all brands.