Alk: the most important test you run...

Sk8r

Staff member
RC Mod
Run it. Now. To see where you are.
If ever things are going squirrel-ey---test your alk.

...Then test it weekly, during your first half year. Bi-weekly thereafter. This is for fish-onlies AND for reefs both softie and stony. For all tanks. Alkalinity is THE most important test for a reef, once you pass your cycling hurdle. And for a fish-only, alk controls so very much regarding fish health, just consider it an absolute essential. If it's right, you've got a major part of fish-care taken care of.

Alkalinity should be around 8.3-9.3 on the DKH scale. It's a reliable guide to the rest of the chemistry of your tank, because if alk is dropping, things are going 'off' and need fixing---urgently.

Alk being off can cause 1) mysterious invert deaths 2) mysterious fish deaths 3) irritability among your tank population, ie fighting and nipping, because if the alk is off, fish are not comfortable. And it can pave the way for parasites and disease to attack your fish, because it damages your fish's protective slime coat and lets these problems get through.

Alk being off indicates, first, that your magnesium and calcium levels may be out of whack.

If you don't have stony corals or clams, it's easy to keep this balance, and just testing alk will tell you how the water is doing. Of course do your water changes, which supply trace elements aside from the three we're talking about. But because nothing in your tank is sucking up the calcium, your tank will tend to be stable.

If you do have stony corals or clams, you will need to be supplementing calcium constantly, from the first day they wake up and start feeding, or they will start throwing the water 'off'. [They often arrive a little stunned, but if the water is really good, they wake up faster and start feeding faster.]

HOW TO: To get your water in balance, start with magnesium. First test it and bring it to about 1300 or a little higher.
Once you have that, test the alk again, and bring the alk to 8.3.
Then test calcium, and bring the calcium to about 420. Do NOT add the alk buffer and calcium within 8 hours of each other: they'll make a snowstorm and fall out of solution.

Always be aware of expiration dates on your tests: a bad test can lead you to over-do considerably. I once calcified all my pipes---not realizing the alk test was giving me a wrong result. That was a mess that took some real work to undo, and it didn't please the tank, either. It's also a good idea to write down your result, so you can see that the alk was 8.4 last week and is 8.3 this week: that means---run your other checks and see if your magnesium is depleted. Magnesium running low is the one that starts the slide toward 'not-good'. So while magnesium is the fussiest of the tests, and alk is the easiest, you don't have to do the mag test unless the alk is dropping---because if the alk is ok, everything else is. Which is a good thing, because it's a real snap to run the alk test.

HOW I DO IT: I use Salifert tests for those 3 items, and for supplements I use Kent Tech-M (magnesium), and Kent Turbo Calcium pellets, and Kent DKH Alkalinity buffer. Because I have stony coral, I first get the reading where I want it, then I put Mrs. Wages Pickling Lime into my topoff water. [Supplies calcium.] That will often keep the water 'locked' in a good state for a month or so---I refill the topoff during that time, of course!---The neat thing about the pickling lime is that ONLY the right amount can dissolve, so it's pretty easy and safe.

Always, especially if you don't have a sump, dissolve or dilute these products before pouring in: dip up a gallon of water, stir these in, then pour it in somewhat gradually.
 
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