Ca and dKh out of whack?

[gibson981]

I am using API test kits, liquid drops. I just got a reading of 380 for Ca, and well over 20 dKh. Does that even sound right?

[TheReef180]

your cal seems good but.... dkh in normall sea water is 8 and you are at 20++.... i think that you alk is probly high also which isnt good

[redfishsc]

Possible.

BTW I have the API kH kit. It's easy to over-read the kit if you aren't paying REAL close attention to the color change-- it is subtle sometimes.

[barjam]

I would make sure the test tube was cleaned out very, very well and try again.

[gibson981]

<a href=showthread.php?s=&postid=13991875#post13991875 target=_blank>Originally posted</a> by TheReef180
your cal seems good but.... dkh in normall sea water is 8 and you are at 20++.... i think that you alk is probly high also which isnt good

If my alk is high, is that what's causing my dKh to be high? What's the best way to get my alk and dKh down? I don't want to sacrifice Ca to do it. I have a couple of clams and some LPS.

[Percula9]

Dkh is the unit by which alkalinity is measured. They are not separate things. If you are adding buffer to the water then stop. Add a calcium supplement to keep the calcium up. The high alkalinity is probably precipitating some of the calcium out.

[Origami2547]

Unless you're seeing problems in the health of your organisms, you can just let the alk drop naturally. You'll find that it drops faster, by proportion, than calcium (2.8 dkH for every 20 ppm calcium). Thus, as Percula9 advises, use a calcium supplement in the interim and allow your alk to drop naturally.

[HighlandReefer]

Most salt mixes have an alk. range between 8 -12. Unless you have been adding a lot of buffer, kalk or other alk. supplement than the reading you have is not correct. It would take a lot of alk. supplement to get to that high of a reading. What are you supplementing your tank with? Another possible problem would be with what you are measuring you salinity with. If you are using a hydrometer, they can be off quite a bit, which would result in higher alk. in your tank, but your calcium should be high also and it is not.

[gibson981]

I have not added anything to my tank other than running a GEO 612 Ca reactor. About 3 weeks ago, I ran out of CO2 and was unable to get my bottle refilled for 2 weeks. I got it refilled a week ago and started it back up. So, 2 weeks without a calcium reactor, followed by the past week with it. The test results were from yesterday. It sounds to me like my API test kits are not at all accurate. Maybe I should pick up some Salifert kits. That is, unless there are some more accurate kits.

[Percula9]

The calcium reactor is what is causing your alkalinity to be so high. The test kit is accurate. Shut down your reactor until alk drops to a normal level. Then restart the reactor with a slower CO2 injection rate. Calcium reactors just don't raise calcium levels, also alkalinity.

[Billybeau1]

Gerald, are you saying it took 20 drops of solution to turn the test vial yellow?

Are you shaking after each drop ?

[gibson981]

<a href=showthread.php?s=&postid=13998070#post13998070 target=_blank>Originally posted</a> by Billybeau1
Gerald, are you saying it took 20 drops of solution to turn the test vial yellow?

Are you shaking after each drop ?

Yes. I lost count around drop 18 or so. A few drops later, the color changed. I am shaking after each drop. Not vigorously, just a couple of good shakes, with the cap on the vial.

[gibson981]

<a href=showthread.php?s=&postid=13998055#post13998055 target=_blank>Originally posted</a> by Percula9
The calcium reactor is what is causing your alkalinity to be so high. The test kit is accurate. Shut down your reactor until alk drops to a normal level. Then restart the reactor with a slower CO2 injection rate. Calcium reactors just don't raise calcium levels, also alkalinity.

I will do as you say and shut down my reactor until I get a better test result and restart with a slower CO2 injection rate. However, when I have run slower CO2 rates, the pH never gets down any lower than about 6.9 inside the reactor. According to the pH controller. The probe was calibrated when I started this thing up in August. The probe is in the lid of the reactor. I am using Gen X media. Doesn't that need to get to about 6.4 before it will dissolve? If I slow the CO2 rate, how do I get the pH inside the reactor to get down where the media will dissolve?

[Percula9]

Can you control the flow rate of the effluent? The pH of the effluent can be from 6.5 to 6.7 and still get dissolution of the media. Right now get the alk in line and then worry about the reactor. I think calcium reactors are more trouble than they are worth.