Alkalinity - How High Does it have to be to Kill or Negatively Affect Coral?

[that Reef Guy]

Alkalinity - How High Does it have to be to Kill or Negatively Affect Coral?

I ask because I have a Newly set up Frag Tank (19 Days Old) where the Alkalinity Keeps Rising.

I am not dosing or adding any type of food or doing any water changes at all.

Yet It keeps rising slowly.

Currently it is at 11.4 which is outside the range of 7-11

I only have Zoanthids in there and they look fine but how much Alkalinity can they take?

I am currently working on finding a salt with lower salinity so I can lower it.

I was talking to a guy the other day and he said he knew a guy that always kept his tank at 15 Alkalinty which I thought was insane (This was an SPS dominated Tank too by the way).

Is that even possible?

If so then I would assume I should not be concerned about my Zoanthid only Tank being just over 11.

But then why does everyone say that Alkalinity should be between 7 and 11?

I mean there must be a reason right?

I was also amazed to learn what my Alkalinity used to be!

I used to use Well Water for the first year of Reefing and had no problems at all.

Out of curiosity I made some Salt Water with my Well Water to see what my Alkalinity was 5 Years ago when I started this Hobby.

20.2 (Yes that is right 20.2 Alkalinity) and I never had any problems.

So do I need to be concerned about my Rising Alkalinity or am I overreating?

 

[vladandlilith]

I have multiple tanks. Some take care of themselves with me never dosing a thing except for one. The one I am talking about is a 52 Bowfront that has been up about two years. my Alk has never been below 12 and when I can get it down to 12 I have a party. It normally stays around 15 or 16 dkh. It is a mixed reef with about 70 plus corals in it. I have to chase my pH with Aquavitro Balance daily. My Params are sg.1.0026, cal. 460, mag. 1320. Alk. 14 as of an hour ago. I have spent a fortune trying to "Fix" this problem. My LPS are doing excellent, and most of my SPS are doing well, too.The only time I have a problem is when I order ACros and they come in RTN.

Alkalinity - How High Does it have to be to Kill or Negatively Affect Coral?

I ask because I have a Newly set up Frag Tank (19 Days Old) where the Alkalinity Keeps Rising.

I am not dosing or adding any type of food or doing any water changes at all.

Yet It keeps rising slowly.

Currently it is at 11.4 which is outside the range of 7-11

I only have Zoanthids in there and they look fine but how much Alkalinity can they take?

I am currently working on finding a salt with lower salinity so I can lower it.

I was talking to a guy the other day and he said he knew a guy that always kept his tank at 15 Alkalinty which I thought was insane (This was an SPS dominated Tank too by the way).

Is that even possible?

If so then I would assume I should not be concerned about my Zoanthid only Tank being just over 11.

But then why does everyone say that Alkalinity should be between 7 and 11?

I mean there must be a reason right?

I was also amazed to learn what my Alkalinity used to be!

I used to use Well Water for the first year of Reefing and had no problems at all.

Out of curiosity I made some Salt Water with my Well Water to see what my Alkalinity was 5 Years ago when I started this Hobby.

20.2 (Yes that is right 20.2 Alkalinity) and I never had any problems.

So do I need to be concerned about my Rising Alkalinity or am I overreating?

 

[Randy Holmes-Farley]

As best I can gather, elevated (stable) alkalinity doesn't usually harm most corals except in ULNS SPS systems, at least in the range up to about 12 dKH. Few tanks are stable long term at levels above that to really have much info.

Elevated alk does have other problems, such as increased precipitation of calcium carbonate on pumps, etc.

I generally would do something if it routinely stayed above 12 dKH.

 

[o2manyfish]

I recently did a test and came up with an alk of 17. I took it in for a double check and with a better Hanna meter they got 18.5 - Tank looks great. Corals have great colors. So I slowed down on the calc rx.

Dave B

 

[that Reef Guy]

As best I can gather, elevated (stable) alkalinity doesn't usually harm most corals except in ULNS SPS systems, at least in the range up to about 12 dKH. Few tanks are stable long term at levels above that to really have much info.

Elevated alk does have other problems, such as increased precipitation of calcium carbonate on pumps, etc.

I generally would do something if it routinely stayed above 12 dKH.

I see some people have a hard time lowering some tanks with High Alkalinity which I understand

But I have heard of people keeping it 15 or higher on purpose by Dosing that High.

What is the reasoning for this?

Why would you want something outside the recommended range?

 

[vladandlilith]

Help Dr. Holmes-Farley

As best I can gather, elevated (stable) alkalinity doesn't usually harm most corals except in ULNS SPS systems, at least in the range up to about 12 dKH. Few tanks are stable long term at levels above that to really have much info.

Elevated alk does have other problems, such as increased precipitation of calcium carbonate on pumps, etc.

I generally would do something if it routinely stayed above 12 dKH.

Dr. Holmes-Farley,
Even with my alk so high, I can't keep my pH up. I have spent many hours with a friend of mine from Seachem trying to figure out what is going on. Do you have any suggestions and also how would I lower my Alk then raise my pH. I've done everything from different buffers to kalk drip to changing my salt to the Regular Red Sea salt mix which after researching appears to have th lowest Alk. My airline from my skimmer is even ran outside. I welcome any advice that you are willing to give.
Thank you,
Sean

 

[brandon429]

What has been the impact to your tank regarding the pH issue you are mentioning

 

[brandon429]

Add some more corals and have fun
Use good source water ro/di
If not accessible then high alk is your mode, many with instant ocean are similar... thankfully tanks are ok with some variance and as Randy said ULNS tanks have more of a concern

Your pics showed no bad algae they looked good. Was this the tank that had bryopsis

 

[Randy Holmes-Farley]

I see some people have a hard time lowering some tanks with High Alkalinity which I understand

But I have heard of people keeping it 15 or higher on purpose by Dosing that High.

What is the reasoning for this?

Why would you want something outside the recommended range?

Many hard corals grow faster at higher alkalinity. It also keeps pH higher, which in turn also boost growth of some corals. Perhaps that is why they do it, but i don't really know.

 

[Randy Holmes-Farley]

Dr. Holmes-Farley,
Even with my alk so high, I can't keep my pH up. I have spent many hours with a friend of mine from Seachem trying to figure out what is going on. Do you have any suggestions and also how would I lower my Alk then raise my pH. I've done everything from different buffers to kalk drip to changing my salt to the Regular Red Sea salt mix which after researching appears to have th lowest Alk. My airline from my skimmer is even ran outside. I welcome any advice that you are willing to give.
Thank you,
Sean

There's no uncertainty that if alkalinity is normal or higher and pH is low, the tank has excess CO2 in it, and usually that comes from elevated home CO2.

Outside air, limewater, and CO2 scrubbers are the best bet, but too much aeration through the tank top can overpower these improvements

This has more, including some tests to evaluate the home CO2 contribution:

Low pH: Causes and Cures by Randy Holmes-Farley - Reefkeeping.com

 

[vladandlilith]

What has been the impact to your tank regarding the pH issue you are mentioning

Suprisingly, I have not really had many negative results except for with Fromia Starfish. The red with black tips do not do that well, however the marbled or tiled variety does just fine.

 

[Scott.h]

As best I can gather, elevated (stable) alkalinity doesn't usually harm most corals except in ULNS SPS systems, at least in the range up to about 12 dKH. Few tanks are stable long term at levels above that to really have much info.

Elevated alk does have other problems, such as increased precipitation of calcium carbonate on pumps, etc.

I generally would do something if it routinely stayed above 12 dKH.

Other then salt and minerals in the water source what are the variables that keep it elevated? My parimeters are in check with a KH of 11. I use RO with a TDS reading of 2, switched salts which test 8 after mixed, dose acid to lower even more before my water change.. Water in the tank 11. PH is consistently 8.2. Could it be something in "fuel"? I don't understand the chemistry beyond that. although everything is in check I'd like to have a better understanding on the "why" and how to lower it further

 

[Randy Holmes-Farley]

Other then salt and minerals in the water source what are the variables that keep it elevated? My parimeters are in check with a KH of 11. I use RO with a TDS reading of 2, switched salts which test 8 after mixed, dose acid to lower even more before my water change.. Water in the tank 11. PH is consistently 8.2. Could it be something in "fuel"? I don't understand the chemistry beyond that. although everything is in check I'd like to have a better understanding on the "why" and how to lower it further

Artificial rock containing cement will steadily boost pH and alkalinity if not fully cured and very well washed prior to use.

I would not expect fuel to boost alk significantly, but I cannot be certain that they are listing the exact form of additives like ascorbic acid. Ascorbic acid, for example, does not boost alk, but if they used sodium ascorbate, it would to a small extent.

RO water with a TDS of 2 ppm might boost alk a little bit over time, depending on what it actually was that was in the water,.

 

[Scott.h]

Thanks, That makes sense. What does the ph and kh run in your tank?

 

[Randy Holmes-Farley]

I rarely measure alkalinity (or anything else except temp and salinity), and it may vary with season since my limewater delivery is dependent on evaporation, but usually it is in the 7-9 dKH range. The ph ran 8.35 to 8.55 for years, but when I got new storm windows, it began to run lower. The pH is kept up in my tank because I use limewater.

 

[Scott.h]

Wow that makes me feel crazy for chasing numbers like I do. Do you supplement magnesium as well or just the lime water? You just rely on regular water changes to keep the levels with the exception of calcium? From what I've seen in pictures you have a fair amount of stuff in there and your water volume isn't incredibly high.

 

[Randy Holmes-Farley]

Wow that makes me feel crazy for chasing numbers like I do. Do you supplement magnesium as well or just the lime water? You just rely on regular water changes to keep the levels with the exception of calcium? From what I've seen in pictures you have a fair amount of stuff in there and your water volume isn't incredibly high.

I had been adding a fixed amount of magnesium to my salt water used for water changes (regular Instant Ocean). IMO, loads of people would be successful that way without testing for it.

I recently had a Triton test and magnesium came out on the high side (1499 ppm) so I decided to back off on the extra added to the salt mix. Here's an article on my results:

http://www.reefedition.com/my-triton-testing-results-by-randy-holmes-farley/

 

[Scott.h]

I had been adding a fixed amount of magnesium to my salt water used for water changes (regular Instant Ocean). IMO, loads of people would be successful that way without testing for it.

I recently had a Triton test and magnesium came out on the high side (1499 ppm) so I decided to back off on the extra added to the salt mix. Here's an article on my results:

http://www.reefedition.com/my-triton-testing-results-by-randy-holmes-farley/

Wow thanks for that. You've confirmed my suspicions on several different accounts. I am shocked you went with instant ocean though. I recently switched from reef crystals because it was so inconsistent from batch to batch, as well as higher kh. I also found magnesium being a bit low.. 1200 ish, so I'm surprised you found elevated levels in the IO. But I'd suspect it was a build up over time. I'll admit I'm a little ocd as I enjoy fiddling with the chemistry and trying to understand it as much as keeping the inhabitants itself, but as you've concluded keeping a few things consistent really does seem to sort itself out.

 

[Scott.h]

I know IO has lower kh freshly mixed (7-8?) then reef crystals, but if you are only using kalkwasser to supplement Ca I'd assume you'd have to be using a fair amount of it regularly. I guess my only question would be how are you keeping your kh below 9 without also dosing acid? Is it just the way you system happens to be, or is it that it may be higher now and you just aren't testing for it because it's not a concern?

 

[FLSharkvictim]

I keep my Alk @ 11.5dKH and my Cal at around 450ppm range but for some odd reason, I can't keep my MAG stable @1350ppm! I have mainly LPS and some soft coralS in my display. I currently dose 5mls of Alk and 5 mls of Cal and 25mls of MAG in the morning and 25mls in the evening but still can't keep MAG stable. I have been using Elos Expert line buffer to raise very slowing my MAG to 1350 over a matter of 4-5 days to get it @ 1350 but just after about a week up 10 days it drops down to 1150ppm! Could it be the salt that my LFS uses maybe since I do a 10-gallon water change every week? Any suggest or thoughts would be greatly appreciated?

Tank info: 120 reef mainly LPS & SOFT CORALS