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Falling Alk. Steady Calc and Mag.


ElmoC

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My tank has been up for a bit over a month. After it finished cycling, I started testing Calc/Alk/Mag (didn't do it before because I hadn't bought the tests). They were all fairly low so I dosed all 3 and got them to proper levels. However, since then, Alk just keeps dropping but the cal and mag are holding pretty steady. I know that corals will consume these things, but I don't have any in my tank yet. I have about 20 lbs of Reef Cleaners dead live rock (got to love that naming) and added about 7 lbs of live rock and 40 lbs of live sand from the LFS to start the cycle. I have since added a CUC, lawnmower blenny, PJ Cardinal and just added a Yellow Banded Shrimp a couple days ago.

 

If you follow the link in my signature, you can see my parameters over time. I can dose to get Alk up, did that once before using baking soda, but it just keeps falling. Last time I dosed with Salifert All-In-One and liquid magnesium.

 

Is this normal for what I have in my tank? I want to make sure my water params are stable before I add any corals.

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Hey maybe you have some coralline algae spore taking root and growing! it does eat up cal and alk like coral, just not alot. The reason why you notice your alk falling faster then your other parameters is because alk is naturally present in sea water at less concentrations. If your alk is at 8, which is a decent level, then you only have about 143 ppm of Co3 equivilents in your water vs the maybe 420 ppm of calcium and the 1300 ppm of mag. Lets say you lose 5 ppm per day of both Ca and CO3 your test kit may not even notice the miniscule drop in calcium since you went from 420 to 415 which is less then a 2% drop vs. close to 5% for alk. So yeah your alk seems to drop faster but they drop at a 1:1 ratio to form CaCO3. Just youll notice the cal takes much longer to deplete and alk requires much more doseage to keep stable.

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Nano sapiens

Once your cal, alk and mag are at the proper levels you can then begin using a balanced cal/alk dosing method. Kalkwasser or '2-part' products (used as directed) are appropriate.

 

If alk is dropping, but cal appears to be 'stable', this not actually the case since alk will show a drop much faster than cal (but cal is still dropping, too, you just can't see it as easily with your test kit). in this case, you need to slowly increase whatever balanced supplement you are using until alk stabilizes. Once alk usage has stabilized, cal will also be stable.

 

In a properly dosed system, over weeks or months alk can slowly start to drop in relation to cal due to bacterial processes. This is where an alk buffer comes into play to restore the tank's correct alk to cal ratio for calcifying organisms.

 

If you'd like to know more head over to Advanced Aquarist and do a search on calcium, alkalinity and magnesium. You'll find some interesting articles from Randy Homes-Farley (mostly) discussing all this in more detail.

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Thanks. So in other words, all is normal? :)

 

yeah i would think so, you'll just have to familiarize yourself with how to keep your levels stable, specifically alkilinity if you plan on hosting corals later on. If that is your plan i would research 2 part dosing. Bulk Reef supply has excellent two part along with video instructions and a dosing calculator. I would start by watching their 2 part video on youtube.

 

 

nano sapien recommend some reading by Randy Homes Farley, i totally agree. He is a well versed reef chemist that has years of experience with scientific research to back everything.

 

Here is an article that he wrote about proper levels:

 

http://www.reefkeeping.com/issues/2004-05/rhf/index.php

 

Here is how to mix the stuff and how to use their calculator:

 

 

If this is something your serious about, be sure to keep up a very regular testing schedule to ensure your not over dosing!!

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Alkalinity is typically consumed much faster and at a much more erratic rate than calcium, especially in new tanks. I've seen it plummet by a full two dKH points in 24 hours on tanks that have patches of diatoms or cyano.

 

How much you want to 'chase it' depends on you. If it's a new tank, you shouldn't be running SPS or calcium sensitive corals anyways. I suggest keeping dKH around 7-8 to keep from going insane. Bump it higher when you have coral that need it. Fish don't care, but it can be hard on LPS if alk is allowed to dive too hard.

 

Again, not sure why anybody would buy baking soda in a bottle of distilled water when a box of it costs .99 cents at the grocery store. 1/4 teaspoon of dry baking soda will raise dKH by about 1-1.2 points per 10 gallons. Never try to raise it by more than 1 point in 24 hours. I add it directly to my tanks by dumping the required powder amount directly in my back filter, and nothing in my tank cares, including SPS.

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as blasterman said, you can make this stuff at home, i just think their videos are really clear and make a tough concept easier to people new to the dosing agenda. I used to use baking soda all the time, works very well.

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