Define an alkalinity swing

HolisticBear · May 27, 2017

I'm curious what people generally refer to as an Alkalinity swing. How particular (fragile) can some corals be?

An Alk swing is a) actual change in dKH b) over what time period c) one time change or a repeated swing up/down

When people mention alk swing, I assume they are mostly referring to a rapid big change due to supplements or water change?

Is not a one-time natural drop from 9dHK to 7dHK drop due to Ca/Alk consumption due to equipment failure, is it? That's not ideal, but that shouldn't cause real harm to an already healthy coral. Or are some things really that fragile?

120reefkeeper · May 27, 2017

To me an Alk swing is defined more as a sudden spike upward of more than 1dkh over a 24 hours period and or a repeated swing back and forth of 1 dkh or more. This is just my opinion.... others may define it differently. Imho through observation I haven't seen an issue with allowing Alkalinity to decrease naturally within a reef system.

Dr. Reef · May 27, 2017

anything over 1-1.5 dkh in one shot is what i consider swing. few points over a day and dosing few points to bring it back is not a swing its daily consumption and dosing.

GoVols · May 27, 2017

Tagging.

Randy Holmes-Farley · May 28, 2017

Part of the presumption of this question must be, how much of a swing is undesirable. In that context, it depends very much on what organisms you are worrying about.

ReeferMaddness843 · May 28, 2017

Picture Reference A:

(couldn't resist)

HolisticBear · May 28, 2017

Randy Holmes-Farley said:
Part of the presumption of this question must be, how much of a swing is undesirable. In that context, it depends very much on what organisms you are worrying about.

Thanks Randy. In threads where people ask for help because their SPS XYZ is not doing well, people often ask if there was an alkalinity swing. So out of curiosity, for the most fragile coral in this hobby, what is an alkalinity swing that causes harm? (not slow growth, but actual harm). Like @120reefkeeper said, I think people are mostly referring to a rapid upward movement or repeated up/downs of what (1.5+ dHK). They are not referring to it naturally dropping 1dHK and then being brought back by a single dosing, or are they? It's something more dramatic, like a quick 7-10 jump or slowly varying between 7-10 during all week, yes?

Randy Holmes-Farley · May 28, 2017

It depends again on exactly what you want to observe, and may depend on nutrient levels.

Folks holding alk very steady (0.2 dKH changes or less at a time) claim that the corals look better, but corals are generally not apparently suffering with changes of 0.5 dKH at a time. If it happens regularly every day, even larger changes may be OK (like once a day dosing), but may not be optimal.

Cory · May 29, 2017

Im mot sure of other corals but my montipora can take swings like a champion.

Id say you should try and keep alk swings no more than 1dkh every 12 hours. But more sensitive species like birdsnest might be upset with that.

bobyboy · May 30, 2017

My Alk drops 1-2 DKH daily and I dose it back up of a night, haven't noticed and harm in corals or stunted growth.
Even my birds nest is big and happy

McGee · May 30, 2017

I am by no means an expert but I think it takes more than just an alkaline the swing I think combined with temperature swings Or poor water quality the corals become unstable. Just don't think it's one thing all by itself

AquamanE · May 30, 2017

bobyboy said:
My Alk drops 1-2 DKH daily and I dose it back up of a night, haven't noticed and harm in corals or stunted growth.
Even my birds nest is big and happy

Maybe I'm wrong but 2 DKH daily swing would be frowned apon by Acros, imho.

Dr. Reef · May 30, 2017

FWIW there are tanks that consume 3 dkh per day. There is no way to control the swing on such tanks except for minimizing it by means of constant small doses or by cal rx.

Tapio · May 31, 2017

I normally don't comment much here because Randy is doing a great job. For me I keep mostly SPS which are most sensitive to alkalinity swings. Typically I have no wild swings, but I have had low of 6 while I usually keep around 8 dKh. Nothing too bad has happened, but I know it can. It very much depends on health of the colonies too. I don't pay much attention to phosphate or nitrate but they are in the low range, especially nitrates. Done this for good 27 years with acropora.

Scott.h · May 31, 2017

Lowering in my experience hasn't been a problem. It's the raising. I'm also curious as if a coral is used to a rock steady number if it's more prone to a shock. I'm also fairly convinced that this is relative to the maturity of the tank and nutrient levels. With a dosing pump you can test mine day or night and it's within .1. Before I got it that stable I've seen the tips of certain sps (not all) not like swings of .5-1.0. That was running near undetectable nutrients and in a fairly new tank. So I may be a little OCD now, but I test at least every other day as I have lots of coin into corals.

Oberst Oswald · May 31, 2017

Cory said:
Im mot sure of other corals but my montipora can take swings like a champion.

Id say you should try and keep alk swings no more than 1dkh every 12 hours. But more sensitive species like birdsnest might be upset with that.

So is it safe to say if your birdnest coral (taught this is a real easy coral to have) is doing great/good there would be no worries about alk swings?

Cory · May 31, 2017

Oberst Oswald said:
So is it safe to say if your birdnest coral (taught this is a real easy coral to have) is doing great/good there would be no worries about alk swings?

I cant say with 100% truth, but yeah your probably doing good. If it aint broke dont fix it.