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]

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]

...
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]

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]

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.

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.

 

[neilanh]

I don't think I agree with them getting depleted at the same ratio... Rather I believe that I tailor each of the 2-parts individually. Meaning if I need xxml of Ca each day, Alk will have a different daily need. So even though it's a 2-part whatever, its 2 seperate things that get tweaked individually.

So like I said, I'm currently doing 70ml/day of Alk and it's not going up. If I test in the hours immediately following the dose, it is higher by 1.5dKh, reading at around 8.5 or so. But I'll bet you a frag tomorrow before I dose again it's down to 7 again.

If it keeps coming back down, there's no way I'll ever get it up to 'target' levels, irregardless of whether or not I'm able to maintain it if it ever did get there. I'm sure not going to go dump 200ml of alk into the tank in an attempt to get it up there. So, I really have no idea what to do.

 

[Innovator]

Your within acceptable ranges so you could very well just leave well enough alone. I take it you are familiar with the 'Reef Chemistry Calculator' to help identify how much of what you'll need to raise by X amount?

 

[neilanh]

Yes, I'm familiar. The generic one I've found online doesn't account for the BRS mixes, but BRS supplies a calc on their site that I've been using.

I agree, I'm within range, but I'm on the low end and was hoping the 2-part would help push me into the mid range.

 

[Kurt_Nelson]

I was going to say the same as Innovator... granted, 7 isn't between the normal 8-12 that's normally recommended, but it's pretty darn close. Probably well within the accuracy range of our test kits. My tank comes in at 7 at the end of the day often. I'd like it to be higher, but I'm not seeing any issues or problems, so I just let it do what it wants to do. For my 46g, I'm dosing 20 ml of both A and B per day. Calcium stays at 410-ish and alkalinity hovers between 7 and 9 dkH.

If you're not seeing any issues, I wouldn't stress about it. Shoot... maybe get a different test kit and you'll get better numbers!

 

[thincat]

Guys can't neilanh dose twice a day until he gets to his target? IDK maybe 40-40 or something like that.

 

[Tank2379]

As, I notice your thread build and with the amount of SPS and LPS in your tank I would believe that's the cause if it dropping down every night. But I would look at a couple different areas before dosing 70ml into your tank? Have you contacted BRS about there 2- part system maybe you have a Imbalance solution or maybe they did not mix there 2 part correctly? I don't know just a guess. I know a lot of folks that use Baking soda to raise there Alk and I heard that does a good job. Or you can try switching to a different brand. What are you Mag reading? I heard over time RC can get your mag level extremely high around 1500ppm I would check to see I heard if it to high it can cause you alk not to raise? But I could be wrong....

 

[ccCapt]

A Simplified Guide to the Relationship Between Calcium, Alkalinity, Magnesium and pH
When calcium carbonate precipitates, it uses up a fixed ratio of calcium and carbonate (1:1, or about 20 ppm of calcium for each 1 meq/L (2.8 dKH) of alkalinity). This ratio is the same as corals use to deposit their calcium carbonate skeletons. Abiotic precipitation of calcium carbonate, like coral skeletal formation, can incorporate other ions, such as magnesium and strontium. That incorporation will reduce the above ratio from 20 ppm calcium for each 1 meq/L of alkalinity to a slightly lower value. Over the long term this process can deplete magnesium and strontium in an aquarium if only calcium and alkalinity are supplemented.

So like I said, I'm currently doing 70ml/day of Alk and it's not going up.

I dose aprox 260ml of ca and alk per day....which means my corals are consuming aprox 18ppm ca and 1 meq/l alk per day.

 

[neilanh]

I've thought about contacting BRS to see what they say, but haven't yet done it yet.

Larry that's good info, thanks. Makes me less scared to know that you dose that much daily in your tank too. I just know all the warnings I've read say not to increase it by more than 1dKh per day to keep from causing a major pH shift (albeit temporary) and shocking everything, so that part has me nervous.

 

[fishmonkey]

-Conduct a partial water change
-If its still low after a day, use an aquarium buffer
- use a solution of calcium hydroxide or kalkwasser