View Full Version : 14 dkh alk, is that passed the too high mark?

08/08/2017, 09:24 AM
I have not been testing my alk and Ca weekly like I should!
It's been really stable at about 11 dkh and about 450 ppm Ca.
But I took a reading last night and it was 14. I am pretty sure that it can be too high. Is this considered dangerous?

Is it possible this could be the reason for a partly dead monti digitata that has been growing like a weed for months? An acro frag I have has stopped showing polyp extenion.. and a goni has not been looking so good (a red short tentacle one). My other acros look really really good, though.

Can these spotty declined corals be because of the high DkH. I actually hope that's the case, as I'd like an 'easy answer' to their issues. If 14 is not too high, then what is?

I'm using an amazing Ca Reactor since late last year. I guess I didnt get accustomed to a possibility of too high Ca or ALK, as before the reactor I could never keep the alk above 7.5 more than a day.

I'm going to target now for 10 dkh and test weekly.


08/08/2017, 09:35 AM
alk should ride at 7.9 to 9.0. 11 is not going to kill anything, I would think, but 14 is not good. Do some water changes with a low-magnesium salt water. (Mg locks the alk and cal until it falls below 1200.)

08/08/2017, 10:32 AM
Recommended range is 7-11dKH

"stability" is more important than a specific value for the most part..

Many tanks can/do run higher than 11 due to high ALK salt mixes,etc... and corals can adapt "fairly" well to that..

It certainly can be the cause of coral issues though.. Specifically the swing/change and even the higher number can cause alk burn on occasion..

08/08/2017, 10:57 AM
I dont know of low mg salt water. I have my Ca reactor on almost no CO2 bubbling. So I'm going to test daily until i get to 9 or so. I'm thinking it will be gradual enough a decline. If the corals are using the Ca and Alk (and therefore the burning) then it makes sense the Mg is allowing the levels to get higher, but not preventing them from going lower (?) .
Testing will show the answer :-D ...

08/08/2017, 11:04 AM
I am in a similar situation actually. I messed up and was adding some buffer to get to 8.3 pH as mine runs very low naturally (stupid me) and for what ever reason, forgot that it increases alk. Mine is now also at 14. I haven't seen any issues yet, but will be stopping alk dosing and let it drop back down. I've been worried that something bad is imminent because I've never let it get above 11 before, and usually maintain around 9.

08/08/2017, 11:34 AM
devastator, are you seeing any negative difference in your corals like I have? I'm pretty sure if we just stop dosing (me stop the CA reactor) it would have to slowly decrease. When I used to dose by liquid, your issue woudl be solved in a few hours :). So you might want to check daily until you're back where you need to be, and not let it get too low.

08/08/2017, 10:29 PM
actually i was at 13 dkh. Which is still too high.
Tonight (less than 24 hrs later) I'm at 11.3. So I'll leave the CO2 feed off for another day.
As suspected, with fair levels (1350 ppm) of Mg, Alk will still be able to decrease.

08/09/2017, 08:20 AM
I haven't seen any negative effects that I can tell. Still have great PE, and coloration is the same. I do have a pink monti that looks like a couple of it's tips may be a tad miscolored, but not enough that's it's caused any concern. Could just be me being paranoid. I've stopped dosing for a day, but haven't checked my alk again yet. I'll check today.

08/09/2017, 08:44 AM
I've had my monti digitata that has grown by about 10x from when I got it 8 months ago, half die off since my alk was too high. Again, I don't know if that was the cause. The other cause is that I didn't know one of my DI carts was likely exhausted. But interesting we both have/had high alk and monti is reacting negative.

08/09/2017, 10:57 AM
I agree 14dkh is high. Stability in alk is key ;variations often result in coral stress even within the rcommended range particualry sps IME. The recommended range is 7 to 11 dkh; nsw is around 7. 8.5 works best for me.