If everyone wants Alkalinity around 8.5 then why do so many salts have higher Alk levels?

[mike550]

The title pretty much says it all. For as long as I’ve been on this board a couple of recurring themes around salt. First, the consensus is that folks want to keep their Alkalinity around 8.5 dKH. Second, the general recommendation is to find a salt close to your target parameters.

So that said, why do so many salts have higher Alk levels? For example Instant Ocean (both types), Reef Crystals, and Tropic Marin Classic.

 

[MNFish]

Some people like higher alk and belive higher alk will increase sps growth.

 

[Lavey29]

A lot of salt brand have 2 types. One with higher alk content and one with lower to give you the option

 

[mike550]

A lot of salt brand have 2 types. One with higher alk content and one with lower to give you the option

That's what I thought as well. But even here's a chart from another thread within R2R. Most of the salts (including both IO salts) are higher than 8.5 or so. Not saying that these numbers are correct, but illustrative for sure -- there are similar tables throughout R2R. And I understand @MNFish comment, but if the "general" view is for hobbyists to maintain All around 8.5 then I would think we'd see more salts with lower Alk levels.

 

[gbroadbridge]

The title pretty much says it all. For as long as I’ve been on this board a couple of recurring themes around salt. First, the consensus is that folks want to keep their Alkalinity around 8.5 dKH. Second, the general recommendation is to find a salt close to your target parameters.

So that said, why do so many salts have higher Alk levels? For example Instant Ocean (both types), Reef Crystals, and Tropic Marin Classic.

Historical reasons.

A few years back, everyone was pushing high Alk, High pH, and Low Nutrient as the way to maximize growth and coloration.

It worked out that a lot of that was counterproductive unless you were really diligent with tank maintenance/chemistry.

So we're slowly wandering back to around 7.7dkh which is NSW level, and a lot of tanks are happier and we're seeing a lot more success stories.

I think high Alk mixes will become more and more niche over the coming years.

 

[taricha]

In a brand new tank, if the salt mixes higher than target alk - it gives you a good long time to get stuff figured out before you need to start adding alkalinity.

 

[Randy Holmes-Farley]

It’s also not necessary for the tank to match the salt unless you do fairly large water changes.

 

[Randy Holmes-Farley]

And I understand @MNFish comment, but if the "general" view is for hobbyists to maintain All around 8.5 then I would think we'd see more salts with lower Alk levels.

FWIW, I do not think there is a consensus alk level that folks like.

 

[Lavey29]

That's what I thought as well. But even here's a chart from another thread within R2R. Most of the salts (including both IO salts) are higher than 8.5 or so. Not saying that these numbers are correct, but illustrative for sure -- there are similar tables throughout R2R. And I understand @MNFish comment, but if the "general" view is for hobbyists to maintain All around 8.5 then I would think we'd see more salts with lower Alk levels.

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Ok so 7 on your list are high alk and 5 are lower alk mixes. Pretty much an even selection that you posted. I use coral pro salt which is high alk mix yet my alk is maintained at 8.3DKH I do 18% water change every 3 weeks. My water change bumps my alk to 8.6 but the next day it's 8.3 again. There's plenty of options to run any level you choose

 

[90's reefer]

Well after 30+ years of doing this I prefer an alk of 7. I have to lower alk once a month when doing small 10% water changes with the salt I use.

If its good enough for the ocean its good enough for me, lol.

One issue I do have is certain coral vendors, I wont name them, insist that alk be 8.5-9. They say this is what ocean levels are.

Average ocean alk is 6.5 so?

Anyway no issue running higher alk as long as its controlled.

 

[JimWelsh]

I see people throw around all sorts of numbers for what typical NSW alkalinity levels are. The Scripps Institution has been providing Certified Reference Material for decades. The values for the most recent batch can be found here: https://www.ncei.noaa.gov/access/oc...system/oceans/Dickson_CRM/rmdata/Batch204.pdf.

This batch has 2202.12 umol per kg of total alkalinity at 20C, with a salinity of 33.494. Converting this to dKH/L at a salinity of 35 at 20C = 2202.12 * 35 / 33.494 * 1.024768 / 1000 * 2.8 = 6.603 dKH. Doing the same calculation on prior batches going back decades, you'll find the values typically range from 6.60 to 6.63 dKH. So, it's fair and accurate to say ocean alkalinity is typically 6.6 dKH.