Why do a lot of reefers keep a lower alk in their tank (8-9)?

[Magellan]

Corals get majority of their food from photosynthesis, in the form of Carbon. However, they still need to consume Nitrogen and Phosphorus as like Carbon, they are the building blocks of life (this applies to ALL organisms). One way of getting N and P is from zooplankton (that is pretty much what reef roids is).

However, corals don't consume enormous amounts of zooplankton as we think they do. It's the reason why they look bleached (but shiny colored) when a wholesaler brings them in from a transshipment. Just low alk. of 7 dkH, very low nutrients, getting cooked by the sun in the wild. After a while under artificial lights and water, they get more richer colors due to higher nutrients and less light compare to the sun.

The main reason corals are used to consuming zooplankton during the night is because that is when zooplankton arises into the water column. I don't think it would make a difference whether you feed during the day or night. You can always teach coral when it is feeding time. However, since corals mainly feed throughout the night in nature and I'm usually out of home during the day, I just broadcast reef roids during night. However, there is nothing wrong with feeding during the day.

answers like this are what has allowed me to have success in this hobby, thank you sir!! I feed Reef Nutrition’s Phyto Feast (smallest particles so I feed it first) then like an hour later I’ll feed Oyster Feast, and some days I’ll broadcast reef roids as well towards the end of the photo period. It has made a tremendous difference in my tank (colors+growth) since I started feeding. Some of my corals seem to absolutely thrive on the food in the water, like this red mini acan. It has its little feeders out pretty much all day, and has been growing like a weed!

 

[Earl Karl]

What do you consider the happy medium?

9-9.5 dkH

 

[Earl Karl]

answers like this are what has allowed me to have success in this hobby, thank you sir!! I feed Reef Nutrion’s Phyto Feast (smallest particles so I feed it first) then like an hour later I’ll feed Oyster Feast, and some days I’ll broadcast reef roids as well towards the end of the photo period. It has made a tremendous difference in my tank (colors+growth) since I started feeding. Some of my corals seem to absolutely thrive on the food in the water, like this red mini acan. It has its little feeders out pretty much all day, and has been growing like a weed!

Good to know that my answers helps! I always recommended feeding corals, why else would they have mouths? Not feeding would make poor use of their biological function.

 

[madweazl]

7-7.5dKh for me; I try to keep as many parameters as I can closer to natural sea water levels.

 

[Earl Karl]

Just posted an article about my experience in reefkeeping and the experiments I have done in the past. This may very well help people get an idea how to run their reefs.

Correlation of Alkalinity and Nutrients (N and P) From My Experience

 

[Randy Holmes-Farley]

I too subscribe to a lot of the “ratios” hypothesis on cal/alk and nitrate/phosphate

with respect to alk and calcium, ratios do not make sense to me. Just because one is high or low , either accidentally or on purpose, is not a reason the other one should be.

 

[Blue Topia]

When the alkalinity of the ocean is 7ish,I respectfully suggest the question should be rephrased: why does anyone run anything but 7ish?

I get the theoretical arguments about increasing calcification. But in my experience, high alk kills corals, while I have my best survival and growth at NSW levels. Usually SPS. But even zoas can suffer. Not in my tanks, in my tanks zoas appear to be immortal. But I hear about this "zoa melting" thing. And I've noticed that when I sell people zoas, the only time they dont survive is when people put them in tanks with unnaturally high alk (>8)

The only beneficial deviation I've seen from NSW levels is magnesium, which montis seem to love at unnaturally high levels (>1300). Every other time my water chemistry has deviated from NSW my corals have suffered.

My 2c

Higher alk higher buffer. 8.7

 

[rmurken]

My tank is still a FOWLR with some zoas (FZWLR?). Coralline, spirobids and other flora/fauna account for my modest .2 dKh/day or so Alk consumption.

I’d like to keep my Alk in the mid 7s, but my purple IO makes that impossible without muriatic acid and I’m just saying no to that.

My Alk recently went on a two-week ascent and topped out at 9.5, which was really annoying. I have no explanation. Random facts are (1) I’ve been messing with my lighting but nothing radical; (2) my pH was dropping while Alk rising (?!) so I got smart and opened some windows—pH went back up again; (3) my skimmer overflowed and dumped its fetid, stinking contents into my tank; (4) my phosphates used to consistently be zero (running PhosGuard) but now sit at .006 no matter how much I change the phosguard...but hey, that’s actually ok.

Anyhow, none of these things explains my rising alk drama. It’s falling again at the usual rate of about .2 dKh/day and I’ll let it go until a WC or it hits mid-7, when I’ll drip just enough kalk to replace further consumption.

Thanks for listening

 

[EMeyer]

Higher alk higher buffer. 8.7

A higher alk isnt a higher "buffer" when the danger zone is high alkalinity. That has been my experience. When alk dips to 6.5, my corals are fine. When alk hits 8.5, they start to die. So from my perspective, 7 is safer than 8, because its farther from the dangerous region. (I am sure your 8.7 is fine, its not like we can measure such a small difference by eye anyway)

Unless you meant formally in terms of chemistry definitions and buffering capacity. In that case absolutely, the higher the alk the higher the buffer

I say all this knowing other run their tanks at high alk somehow. I've repeated this enough times to know that if my alk goes above 8 in any of my tanks, corals will die. I remain puzzled and intrigued it doesnt act that way for everyone.

 

[Blue Topia]

A higher alk isnt a higher "buffer" when the danger zone is high alkalinity. That has been my experience. When alk dips to 6.5, my corals are fine. When alk hits 8.5, they start to die. So from my perspective, 7 is safer than 8, because its farther from the dangerous region. (I am sure your 8.7 is fine, its not like we can measure such a small difference by eye anyway)

Unless you meant formally in terms of chemistry definitions and buffering capacity. In that case absolutely, the higher the alk the higher the buffer

I say all this knowing other run their tanks at high alk somehow. I've repeated this enough times to know that if my alk goes above 8 in any of my tanks, corals will die. I remain puzzled and intrigued it doesnt act that way for everyone.

From my experience it's the swings that kill and 8 to 9 just gives me a comfort zone.

 

[User1]

Trident says my alk is nominally 9.5; Hanna says it’s 10.5 ..... whom to believe ....

That is interesting. Hanna reads for me 8.1 and my Trident says 8.09. More or less close.