16dkh

[marineer]

Is alk to high at 16dkh? Other parameters are: Sg: 1.26, NO: 0, Ca: 440, Phos: high (working on that with water changes and carbon) NO2:0, PH :8.2.

[marineer]

It's been at the highend for a while. Shouldn't it clime down if i just dose for Calcium? Thanks for the help.

[SJimmyH]

High alkalinity itself doesn't really hurt anything.

Being at the high end can put you closer to the point of precipitating Mg, Ca and Sr though.

Play it by ear, IMO. If you can maintain the rest of your specs without issue than I don't think its a problem. There are others that would disagree, of course, but thats my 2 cents.

Keep in mind that for your alkalinity, you should have a pH of near 8.6. The fact that you don't means you most likely have CO2 in the tank. You can look up articles to help you decipher that and how to fix it here on this web site.

[bertoni]

I would let the alkalinity drop to 11 dKH at most. This article covers all the water parameters:

http://www.reefkeeping.com/issues/2004-05/rhf/index.php

It should drop on its own provided more alkalinity isn't being dosed. Are any pH buffers in use? They are just high-pH alkalinity supplements, and often cause high alkalinity problems.

[SJimmyH]

Ideally, I agree with the lowering alkalinity like bertoni says.

I think the spec given on the link for alkalinity is more to let you know where you should be able to keep it if all conditions are normal. I still don't think a high alkalinity itself is toxic.

If you raise it enough, you could get to the precipitation points of the elements I mentioned in the last post. That could cause some nasty issues that could kill your stock (most likely through a pH crash). You can tell if your Mg is low. You will begin to have issues with keeping Calcium in spec. When this starts happening, you are getting too close to a crash, IMO, and you would want to lower your alkalinity and raise Mg back up (a water change would do this along with adding Mg suppliments).

If you have a CO2 problem (you NEED to rule that out or determine that it is a problem) lowering your alkalinity without doing anything else could give you a very low pH. Just be careful.

Like I said... lots of articles on pH problems (which is what you really have since its taking so much alkalinity to keep your pH in spec) and CO2 here on the web site.