Calcium / alkalinity

Guys,

4 month old tank, 13.5 gallons. Heavily stocked with coral and a couple fish.

Parameters are as follows
PH 7.8 in the morning, 8.2 in the afternoon
Ammonia 0
Nitrite 0
Nitrate 5
Phosphate 0
Calcium 380 - 400
DKH 5

I've started dosing Kent's 2 part for the calcium...its slowly increasing but cannot get the alkalinity to move.

Any thoughts on what's going on?

I do a couple gallon water changes every 3 or 4 weeks.

Trying to learn about water chemistry and just trying to understand and do the best that I can.

Everything appears happy and growing.

TIA

Check magnesium and you might want to slow the addition of calcium while you bring up the alk. From my understanding, alk and cal will combine and precipitate out if one value is too high and this happens at lower levels if magnesium is low.

You'll want to bring the kh up to at least 7 to match a calcium level of 400. 7.5 would be better. Also, kh is a buffer to help keep the ph level from swinging too much. Strontium and magnesium help that to an extent also.

Try to get the kh up to the point that matches the calcium and then watch it for 3 or 4 days without dosing to see how much your tank uses and then dose to keep that stable. Or slowly add more kh over the course of a week, check, and if it's still dropping, increase the dosing, and repeat until you have it in check. Then you'll need to continue checking because as the corals get bigger and the more you add, the more they'll be eating up.

You may need to increase then two part in the calcium due to some systems eating more kh than calcium. It's not always a 1:1 ratio.

You'll also want to get a second check to verify your tests are accurate. Sometimes a bad test kit can give you bad values.

I second Madreefer. Check your Mag level. I bet it is low. I would also look at switching to a salt that is higher Alk level to help keep it at a higher level once your dosing gets the levels back in line.

kevin.st wrote: I would definetely have someone else test your water to verify.  I would very slowly raise that dkh. Mag/calcium/alk are interdependent, btw.

Interdependent is good until you try to change them all at once.

I find it easiest to fix mag first for two reasons. First you can dose quite a lot of it without any negative effect on the system. Second because I have found it near impossible to bring Alk up if Mag is too low.

So I bring up Mag, then verify calcium (it will probably change some with the Mag level corrected) and correct as needed and then start slowly bringing Alk up no more than 1dKh per day and checking the calcium and mag as the Alk comes up (again they will change as the alk level returns to a proper level).

Do you have a picture of the tank so we can see the livestock in it?

double check your test kit for alk.. it might be bad. How have you been dosing it? How often and how much have you dosed over what time period?

Have You gotten test results back on your water from another tester to verify that your kit is working correctly? What were those results?

Aquatic dreams verified my test results yesterday. My test kit is reading accurate.

I've been dosing Alk in the morning and testing at night. Testing calcium at night and then dosing it.

I'm dosing 1 tsp of cal and alk daily.

 

Edited by Mark Peterson - February 25 2017 at 4:26am