High Alk, Low Cal - Best fix

[meitzler]

Using Sailfert test kits, my tank has readings of Alk 15, Calcium 380, and MG of 1480. Temp is 70 degrees. PH is 8.2. The Alk at 15 is way too high. The Calcium is low. What is the best way to correct, that is lower the Alk and increase the Cal? I am also using a GEO calcium reactor with the large Shura type media in the 334 gal tank. The SPSs appear to be doing fine. The tank is setup 6 months.

First thought is Calcium chloride and turn the cal reactor down.

 

[adunn79]

I had the exact same issue, did a few partial water changes and turned off the calcium reactor for a while. Alk went down slowly. Also added Kalkwasser with all topoff water to keep calcium and ph up.

took about a month to drop. Only issue when Alk was high was dead snales when alk was high.

No expert but everything is happy and stable now.

 

[DonW]

I had the exact same issue, did a few partial water changes and turned off the calcium reactor for a while. Alk went down slowly. Also added Kalkwasser with all topoff water to keep calcium and ph up.

took about a month to drop. Only issue when Alk was high was dead snales when alk was high.

No expert but everything is happy and stable now.

Kalk is going to increase alk and ca both. Since you have sps I assume your consuming. I would just turn the co2 off to the ca reactor for a few days. Add enough ca chloride to get the ca up to about 420. That should fix it pretty quick.
Now fix the cause. Why are you lopsided? Did it get this way on its own with just the ca reactor running? Are you using IO salt? Do you balance your salt mix before adding it to the tank for water changes? What is your Mg?

Don

 

[meitzler]

My magnesium is 1450. I did us IO which was a mistake, since I had to add unbelievable amounts of MG to get it to 1450. No I did not balance the salt mix. That is a lesson learned for me. The Calcium reactor appears to keep is stable, I just can not close the gap for the Calcium and reduce the Alk. Corals are fine, but my concern is that may be a short term situation. Thanks so much for your input.

 

[DonW]

My magnesium is 1450. I did us IO which was a mistake, since I had to add unbelievable amounts of MG to get it to 1450. No I did not balance the salt mix. That is a lesson learned for me. The Calcium reactor appears to keep is stable, I just can not close the gap for the Calcium and reduce the Alk. Corals are fine, but my concern is that may be a short term situation. Thanks so much for your input.

Why so high on the Mg? IO is low on ca. Make sure you balance your wc water. Ca chloride will get you much closer and shutting down the carx will drop the alk.

Don

 

[LakeEd]

I agree with Don, in that your Magnesium level is higher than what I shoot for (1250-1300). I use, and like Instant Ocean for my salt mix, because it is very stable from batch to batch for me.

Freshly mixed water (to a S.G. of 1.025) normally tests about Alk 8.5dKh, Calcium 350(ish), and Magnesium about 1100. For me, that alk is about what I'm shooting for, so I just buffer my Calcium & Magnesium up (shooting for Cal level of about 400, and as stated earlier... Mag of 1250-1300) then airate over night before using.

Is it possible, that knowing that your calcium level in your freshly made up water was on the low side, that you buffered the calcium up using Kalk in your water change water... and didn't notice/test for the equal rise in Alk while doing that???

 

[returnofsid]

Hmmm in reading this and with the advice I got on a similar issue, I've come to realize that I should be looking at my water change and top off water as well. Hadn't thought about that...DUH. So, you're saying that I need to be testing my water change and top off water for Ca and Alk as well? Then I also need to be dosing them with the appropriate "stuff" to get them at the same alk/ca targets I want for the tank? DonW, you know the levels I'm looking for...would you suggest I be looking at my WC and top off water as well? Not sure how I'd alter the top off water. Can you use Randy's recipes in freshwater?

 

[DonW]

Hmmm in reading this and with the advice I got on a similar issue, I've come to realize that I should be looking at my water change and top off water as well. Hadn't thought about that...DUH. So, you're saying that I need to be testing my water change and top off water for Ca and Alk as well? Then I also need to be dosing them with the appropriate "stuff" to get them at the same alk/ca targets I want for the tank? DonW, you know the levels I'm looking for...would you suggest I be looking at my WC and top off water as well? Not sure how I'd alter the top off water. Can you use Randy's recipes in freshwater?

Sid
Not your top -off dont touch that. Just the water change water should be balance and its alot easier if it matches where you want your tank to be.

Don

 

[returnofsid]

So I should only need to test my water change water every once in awhile since I use RO/DI...then refer to the chemistry calculator for how to balance it to the same as my display balance...and that should pretty much stay the same each time I mix it shouldn't it? As long as I'm mixing the same amount that is.

 

[meitzler]

The instructions in the Salfert MG test kits indicate that nature ocean water has MG between 1300 and 1500. That is why I adjusted mine to 1450, giving me some latitude in the acceptable range for when it changes. With the discussion so far, maybe I need to understand the best water paramenters for the average SPS corals realizing there are variation depending where they came from. Anyone out there have recommendations based on a very successful tank over a long period of time. I would love to hear the parameters.

 

[Curtswearing]

Anyone out there have recommendations based on a very successful tank over a long period of time. I would love to hear the parameters.

This is a good start. http://www.reefkeeping.com/issues/2004-05/rhf/index.php

 

[meitzler]

Great reference

Great reference. I was surprised at the recommendation not to add iodine. Most sources suggest adding it for software corals. Of course many of us probably add it without understanding the details. OUCH!