Does anyone purposely run low alk reef tanks?

[Gill the 3rd]

Im just curious if anyone runs a lower alk reef tank on purpose? Say around 6-7 dkh. The only reason I ask is because I normally keep my alk consistent between 8-9 dkh. My corals have all been doing well and growing. Ive been renovating my home recently and have let my kalk reservoir empty a few times (due to lack of time) and my alk has dipped down into the 6's on occasion. Just recently it dipped down to 5.5 dkh. Ive always brought it back up slowly with no issues.

The thing is, Ive noticed my corals seem to look better at the lower dkh. I'm thinking of keeping my alk between 6-7 dkh and wondering if anyone else does that? I keep all my other parameters pretty consistent and PH is always between 8.0-8.3.

 

[ReefHunter006]

Mine is between 6.9-7.5.

Every time I attempt to raise it, the sticks throw a fit and die.

 

[Potatohead]

I used to run mine in the high 6's. When I tried to raise it with alk dosing, acros would't be as happy. It wasn't until I tried kalk that I can run it now around 8.5 and the acros are still happy and grow faster. I have no idea why that is. Maybe once my tank is full up and I don't want as much growth I will go back to the old method.

 

[Gill the 3rd]

Interesting. My acros, digis and montis are doing good at both, but definitely have a better color pop at the lower dkh.

 

[VintageReefer]

I typically am 8-8.5. Sometimes I have run 9 and have had zero issues. A few times over the last 2 years its dropped to high 6’s or low 7’s and Maybe it’s coincidence but I always end up with an issue.

Most recently a favia and a lobo frag of mine that weee both doing well took negative turns and are in a declining state. I reviewed photos to see when it began, and it was during an alk drop.

 

[ReefHunter006]

I tried pushing high 8s for a year and for whatever reason my acros hated it. It improved when I dropped it and it’s notable when it raises cause things get *****.

I also have a long history of suffering acros due to other stuff so I wouldn’t base any decision making off my example.

 

[Troylee]

Interesting. My acros, digis and montis are doing good at both, but definitely have a better color pop at the lower dkh.

I’d contribute that to slower growth.. when I ran a lower alk my sticks colored better cause they didn’t have growth tips and stretched flesh over the skeleton.. with a higher dkh my sticks lose color with the white tips and growing faster. I could be totally wrong but that’s what I believe I observe at least in my tank.

 

[BriansBrain]

I run 7-7.5. For me, when I go above 8.5, I always get burnt tips on acros. My lps tank(below), I tested yesterday and was at 6.1. Tanks doing great! In my experience - with my tanks, the higher the alkalinity, the higher chance of issues

 

[KandAReefs]

A lot of it is keeping things stable no matter the number ( within reason) is much more important. Corals will adapt to the tank given time and that's why you see tanks that look great with numbers out of the ordinary.

 

[Miami Reef]

The thing is, Ive noticed my corals seem to look better at the lower dkh.

@Randy Holmes-Farley

How can some people observe better colors at lower alk? Do you think it’s a direct, indirect, or a coincidental relationship?

 

[Formulator]

It is a known phenomenon that low alk tanks tend to have more vibrant colors, but these tanks need to be maintained with ultra low nutrients or you risk burnt tips. Sorry I can’t remember the specific mechanism of action, but I do remember reading about this phenomenon.

 

[PharmrJohn]

My last reef tank I ran 11 or 12. I plan on running the same (as well as Ca and Mg in the higher range). It's gonna be a game but I did it once. I'll do it again.

 

[jackson6745]

I've seen too many tanks and ran tanks with peak color with alk ranges 8-9 dkh to believe that lower alk leads to better color. For some reason guys running stripped nutrients need to run lower alk or things get all wacky with their SPS. Guys with higher nutrients seem to need a higher alk or they will get slow growth with that wrinkly looking skin on many pieces. Of course there is a balance, and some corals are exceptions, my head hurts thinking about it lol