How often do u have to dose alk and cal?

Contemplating starting an SPS tank (I only have LPS experience). I would not have room for a calcium reactor so...

1. how often would I need to dose ?
2. what happens if your levels are too low? Do the SPS die or stop growing or...?

Thank you:)


New member
Dose kalk with your ro/di top-off water and if your calcium is low they just slow way down in growth.


New member
I dose ESV B-Ionic daily for the past 2.5 years...with Kent Tech-M for magnesium every other day to evry fourth day.


New member
<a href=showthread.php?s=&postid=9240369#post9240369 target=_blank>Originally posted</a> by jiggly75
Keeping your calcium level at 400- 450 will aid in calcification your corals need to grow. Depending on your sps load , you will have to dose every day or every week if you only have a few sps.

Here's a cheaper way to dose:

It's a lot cheaper than paying for store bought bottles.

But that takes time and means you need to do it 100% correctly or you could run into problems. But it is much cheaper, and if made right issupposed to be just as good(the same).


New member
i have been using Randys Recipe for over a year now with excellent results. i dose daily, or every other day. each tank is different. you will first need to test you calc and alk. and dose to get them where you want them. then test the next day to see how much gets consumed daily. then you dose, test the next day, and do this for about a week until you know how much you need daily. once you get a routine going you can test weekly, or bi weekly, and adjust from there. as an example i dose 30ml of each part daily. i know if i test today im going to be right on the money with the calc and alk. every time you add a couple of new corals, are as your current corals grow you may have to up the dose some, again its important to test so you know how much is being consumed. heres a great calculator to help with how much to dose.


New member
<a href=showthread.php?s=&postid=9240405#post9240405 target=_blank>Originally posted</a> by E-A-G-L-E-S
But that takes time and means you need to do it 100% correctly or you could run into problems. But it is much cheaper, and if made right issupposed to be just as good(the same).

It's is the same thing you are using just not a quarter of the price! Same chemicals, and with this calculator it's always right on the money by my salifert test kits:


New member
How much and how often depends on you particular tank consumption which will increase as the coral population increases and grows.
If levels fall too low coral growth will stop and in extreme cases the coral tips will deteriorate as not only they can't deposit the calcium carbonate they need but at certain poit it will dissolve.
Usually before that point is reached your PH will be so out of wack that the PH issue will have bigger and faster repercussions.
The recommended levels for Calcium will be 380 to 450 ppm, alkalinity 3 to 4 meq/lt and Magnesium 1250 to 1350 ppm.

Until you get more familiar with it and know how your tank reacts I will recommend to start with a commercial two part supplement so in case you have adjustment problems you do not have to guess if your DIY supplement is at fault.(B-Ionic, Two Little Fishies or Warner Marine will be my preferred).

The two parts will have to be added in the same amount as they are designed to add Calcium exactly in the same proportion as the required Alkalinity. The addition of both is required except with those times were you need to adjust one parameter and not the other. If say your Calcium is low and your alkalinity is high, you can add only the Calcium part and vice versa.

The amount of two parts to add has to be determined by trial and error, in other words, test your level of alkalinity, add the manufacturer recommended amount and test 48 hours later, if dropping increase the amount and viceversa until you find the amount that will keep the alkalinity stable.


Premium Member
Just to second and third the motion for Randy's recipe, and Jdieck's calculator.

Used them both for about a year with good results, I find I have to dose twice a day for my heavy load.

Just watch your salinity as the two part will creep it up.