Depleted Alkalinity; Off the Charts Calcium?
 

Hoping to get some help understanding on what to do here. I have a mixed reef (No fish currently) doing well but my routine tests had me trumped today. My Alkalinity was practically depleted, less than the low 5.3 dkh on the Red Sea test kit. Only .25ml of the Alk titrant was used in the test and was tested twice. :headwally:

Meanwhile calcium, which I understand isn't likely related to my depleted alkalinity, used an entire syringe plus an additional 0.4ml for a total reading well over the 500ppm for a full 1ml of titrant! I must note my pH is lower than I'd prefer, wavering from 7.8 to 8.0.

Can anyone help explain what might be going on? How can I slightly increase pH and Alk and potentially decrease what's going on with the Ca?

Other tank specs:
~40 gallon total system, 7 months old
Currently running Bio-Balls that helped reduce nitrates (Could this be my issue?)
Running Kalkwasser in top off
All other levels in check including Mg, Ammonia, Nitrite, Nitrate, Phosphates

A bit of baking soda will fix the alkalinity problem. I'd dry dosing 1 dKH in the morning, and then checking the dKH in the evening. The tank might consume up to 2-3 dKH per day, so raising the level might require some large doses. This calculator will help with the amount:

http://reef.diesyst.com/chemcalc/chemcalc.html

I'd be careful about large doses if the tank has any touchy stony corals. They might get cranky. :)

With respect to the calcium level, I'd check the levels in some freshly-mixed saltwater. Some mixes come with very high levels, and then there's issues with bad batches of salt. The calcium level is very unlikely to cause problems. You can use two syringes and add the results if you'd like a firm number for the level.

So I don't use bioballs so I can't speak for if your problem is the same overall root cause or not. I run a sulfur denitrantor and it consumes ALK at an unbalanced rate to the amount of Calcium added with Kalk. I only use Kalk for calcium addition today, and evently I'll get calcium to 500 and ALK to 7. Once this happens I just use seachem reef builder in place of my Kalk solution and boost only ALK while not adding calcium...

Sorry, I missed the question about the bio-balls. They will not consume alkalinity directly, but water changes that remove nitrate also remove some alkalinity. The effect overall should be fairly small:

http://reefkeeping.com/issues/2004-12/rhf/index.htm

Most likely, you're just seeing normal consumption. Many tanks consume 2-3 dKH per day.

Dumb question but I did the same when I got the Red Sea a long time ago. You used 10ml of tank water for the Test right? Make sure that's not the problem before dosing. It would still be low but in the 5-6 dkh range with your result. Just thinking aloud. Other than that, what is your Magnesium level? Getting that stable will go a long way in the other falling in line. The others questions are also important to consider

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I keep my mag around 1400-1500 typically using the RedSea Mag Pro test, but also have done some ICP to confirm my battery of tests. Every once in a while I'll end up with a week of dosing mag to raise it back.

Stability is king, so long as your test keeps giving you the same number you can use it as a guide so long as its not to dramatically far off. For example my RedSea kit is always about 50-100ppm lower in mag readings then the ICP test.. Not enough to matter to baddly in this case so long as I keep trying to hold it around 1450.

I keep my Alk now a days between 7-9...

Sorry I have to ask about alk also, mine always seems low, tested 2 days after 20% water change and it is at 5 according thonthe Red Sea test kit, I tested previous water at 8 2 days earlier is this normal? Everything (livestock) seems fine in the tank



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Sounds like a testing error. Have you re-tested? What is the Alk of your water change water?

it's very common to have a 2 dkh drop in a day in a well established tank

Also. Whats your Mag reading? Keeping Alk in order, Magbis an important element. A 5dkh as in the previous post is a large issue but yes, may be a testing error. Red Sea has specific titration steps and reading/filling the syringe correctly is paramount in a propper reading.

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I did not test water before adding. Tank is about 2-3 months old, but somewhat established. Long story , but nut shell version is original lfs that set up and filled tank used water from their tanks, already cycled blah blah blah, but anyhow, I’ll probably re test alk anyway to make sure


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Pretty green at this, I assume your talking about magnesium? The kit I have doesn’t provide that


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I agree that a drop of 2 dKH in a day is within reason. I'd double-check the test kit, though, just in case.

What salt are you using? What salt your using can have a big effect on these numbers. Some salts are low in ALK, like Oceanic.

My tank is 10 months old and my Alk, Ca, and Mg and been constant at 9, 500 and 1550 but my salt mix is 8-9,400-450 and 1350-1450 so I don't dose anything right now.

Get the water from lfs so not sure


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The n txt time you get water you might want to test it. It could be a good part of why your ALK is so low.