Alk Swings - How Much is Too Much?

[rlpardue]

Hi all,

It's been hammered home over and again to keep one's alkalinity as stable as possible. It sounds like keeping tabs on alk is probably the most important aspect of an SPS tank once nutrients are under control. However, as I've searched through older threads I've found a surprising lack of hard numbers re: what exactly is too big of a swing.

Personally, I'm wondering if I am being a bit paranoid with my alkalinity. I burn through a 30-test vial of the Hanna checker alk reagent in about 2 months. I use a LiterMeter3 to dose BRS 2-part and my most dramatic recent swing between testings has been from 7.84 dkh to 8.29 dkh in a week. (Although I saw a swing in one week from 8.17dkh to 7.22dkh when I was getting the LiterMeter dialed in).

My main question: At what point do corals show signs of burning, slower growth, or general irritability?

 

[trueblackpercula]

Plus or minus 2 either way will cause stress

 

[Mr_N1ce]

Hi
The obvious answer is: as little as possible.
But seriously: most people won't even notice such a little swing that you're measuring here as it is not measurable with normal drop tests. So the bigger question is probably if 8 dkh is the right value for your tank.

 

[Touring]

I went as much as 2.5 with no negative results. 7.5 to 10

 

[Spslvr]

i dose mine manually every day [p.i.t.a] mine swings between 8-10 in any given week i have good growth and color and havnt noticed any negative effects.

however i used some tech m to control some bryopsis and noticed with high mag 1600 and kh at 10 my pink birdsnest got tip burn seems with the high mag some sps became more sensitive to higher kh.

just an observation.

 

[rogerwilco357]

My tank went from 10dkh to 15 to 17dkh thanks to straying from Reef crystals to Red Sea Pro man was that hard to bounce back from and yeah I mixed it prior dry to take care of any settlement during shipping but just my luck I guess.

 

[reefmutt]

I couldn't give you a hard number..
As has been mentioned, the more stable the better..
I wouldn't worry too much about you're 1 or so dkh swing..

 

[rovster]

I've noticed the corals tolerate a drop better than an increase. I run an SPS nano, so my parameters probably fluctuate more than most. I aim to keep my Alk between 7-9 However, I really try to keep it around 8. It rarely goes up to 9 or even drop to 7. So my Alk probably hovers within a 1dKH range (7.5-8.5). Colors are just OK in my tank, as well as growth. Easier SPS grow very fast while acros grow slow and steady. Not trying to sound like an expert, far from it. These are my observations of my own tank over the past 18 months or so. FWIW, the only thing automated on my tank is the lights, LOL! Top off and dosing done manually!

 

[theyangman]

I hope my doser makes these scenarios a thing of the past.

I'm still trying to dial it in though and make the transitions smoother. Trying to balance all three is a pita

 

[reefmutt]

This is why I'm still a believer in the good ol' calcium reactor..
I will put a doser on it, however..