I can't keep it up (alk that is)...

[pbanda]

Hey Randy,
I have read all articles about Ca and Alk, but I need some direct help on this one. Here is a brief description of my setup:
55 gal with lots of sps and coraline
Ca Reactor with effluent of 6.75 dripping 13 ml/minute
Ca - 420
Tank ph - 8.1
Alk - 2.75 meq/L

As the subject says I am having a hard to keeping the alk above 2.5 using the fasTest/SeaTest alkalinity test kit. I add Seachem Reef Builder to raise my alk to 3.50-4 meq/L and the next day or so it is back down to 2.50-2.75.

I measured the alk coming out of the reactor and it was 7.75 meq/L. Shouldn't this be high enough to keep the Alk up?? or do I need to drip even faster (keeping ph 6.75)??

thanks,
pbanda

[aquababy]

Just three suggestions - Check your Mg, it should be 1350 - 1500ppm. If it isn't fix it. Kent Mg is a good choice. Mg stabilizes Ca and ALk and most salt mixes fall short of the right amounts. Get a salifert alkalinity test kit (I have been using this one forever and I am convinced it is top of the line) or another brand just to be sure your kit is working accurately. You might instead compare test results with someone who has one of these other brands of kits so you can see if your kit is the same. Next I suggest you try Bionic alkalinity additive. You might have to buy both parts of this two part additive (Ca/ALk) to get the one but they have small sizes. You might find the Bionic satbilizes your ALK much better as it is balanced well.

[Boomer]

I agree with Aqua. Don't forget that those SPS are using that alk, and some is used to negate some organics. Alk will almost always drop faster that Ca. You may want to try a better skimmer also. You really don't need an Alk that high but many like up there. Seawater is only about 2.25. You could lower the reactor pH but then the Ca will also go up. I wouldn't exceed 450 mg / l Ca.. Many people do as Aqua suggested.

[Randy Holmes-Farley]

I expect that you are just not keeping up with the demand.

This article may guide you through the tuning process:

Simon Huntington's CaCO3/CO2 reactor article
http://reefkeeping.com/issues/2002-05/sh/feature/index.htm

[pbanda]

I am gonna try and increase the drip rate and lower the ph to 6.6.
I will also add some buffer to raise the alk.
Hopefully I can keep it up!!

I find it amazing how fast it gets used up!!

thanks,
-pbanda

[Randy Holmes-Farley]

If you find you need "buffer" to keep alkalinity up, then I'd suggest a two part calcium and alkalinity additive, because you also will not be keeping up with calcium, although it will take longer to notice that change.