Help balancing Ca 'n Alk

[reefkeeper]

I have been trying to do a better job getting my tank parameters in order on a consistent basis.  Plus, I adding several corals to my tank lately (as well as a clam), and I really want to see some growth and health in my tank.  I have been testing my water consistently for a week or so and I wanted to check with you all to see if my approach makes sense.  I have been using Randy's recipe #1 to raise Ca and Alk.  As you can  see, my Ca is dead on every 2 days, but my Alk is a pretty inconsistent.  Do my numbers make logical sense?  I thought the point of Randy's recipe was that it was balanced.  Am I going about this the right way?  As such, I expected to add the same volume each time to both Ca and Alk.  By the way, my Mg is at 1410.

                  Current       Added   Goal    Added    Goal
Date         Ca      Alk        Ca       Ca       Alk        Alk
Sun 2/27   390    8.30    368ml   420     100ml     9.5
Wed 3/2    390    7.00    368ml   420     214ml     9.5
Fri 3/4       390    8.00    368ml   420     128ml     9.5
Sun 3/6     390    7.40    368ml   420     180ml     9.5

Thanks -Jeff

[Wall_Tank]

A clam can suck in the CA and Alk.....   but something seems odd.   That is a lot to dose ever two days.    How long are you taking to put in that much volume of the part 1 and part 2?   If you are adding too fast, you can cause precipitate.....

I would dose everyday, and in the amount you are adding, I would probably split it up to a morning and evening dose.   Even better, get yourself two dosing pumps.

Secondly, make sure you mixed your part 1 and part 2 properly.

[larrynews]

i add  both everyday, like a half cup, and since doing that my tank has done great

[mrfish183]

I'm not sure your numbers make exact sense.  Here is why:  After day one addition, your calcium level should have been 410 ppm.  Your alk should have been around 9.1 dKH.  After three days, your Ca dropped to 390 indicating a Ca consumption rate of 20/3 or 6.6 ppm/day.  Your alk dropped to 7.0 indicating an alk consumption of 0.7 dKH/day.  Similar analysis shows average Ca consumption rate of 10 ppm/day for the rest of the week and 0.35 and 0.8 dKH/day for the other periods.  On average for the week, Ca consumption was 8.9 ppm/day and alk was 0.6 dKH/day.  This is not balanced.  For balanced CaCO3 precipitation, 10 ppm of Ca should consume 1.4 dKH. 

This implies either your tests are off, your solutions aren't mixed exactly right, or something in your system is taking lots of Ca, which doesn't make sense w/o a similar drop in alk.  I think your Ca test kit isn't that accurate, which is OK.  Alk is more important to measure because it changes much more rapidly. 

What woud I do?  Similar to what others have suggested, I would not dose alkalinity every two or three days.  Also, I'd test alkalinity after adding it to make sure you are getting the expected increase.  If you do, then good.  If not, then something is wrong with your test kit or solution.  I'd also add equal amounts of alk and cal solutions and stop the varied additions.  I'd start w/140 ml/day of each part.  Wait three days and retest.   

It takes The amount of the CaThis is not balanced consumption for any of the three periods

[lazylivin]

Just to add are you measuring the same time every day. For example if measuring 12 hours after you doing your dosing one day and then measuring 2 hours after doing your dosing another day then it is going to give you in accurate results.

[reefkeeper]

All - Thanks for the advice.  I knew you all would have good ideas!  I am measuring at approx the same time each day (8:00ish PM).  However, I am not rechecking an hour or two after dosing to see if I hit the desired numbers. 

I am using a measuring cup and pouring a little Ca in, then waiting 30-60 seconds and pouring a little more, etc. until it's all in.  Probably takes 3 minutes total.  Ditto for the Alk.  However, the Alk causes some cloudiness (only in the area I poured it), so I wait until the cloudiness clears up so it might take a little longer than with the Ca.  Also, I slide my filter sock out of the way, and pour it into my sump so the water rushing in mixes it well.  I do not get any cloudiness in my tank when dosing.

Any other thoughts?

[reefkeeper]

Just found this on reef central.  The question posed was basically "How much of Randy's are you dosing".  http://www.reefcentral.com/forums/showthread.php?t=1986821