Alkalinity range and too low

ekean

New member
I've been trying to research Alkalinity and it looks like there are some pretty big differences of opinion.

In mid September, I began using the Red Sea line of products - Reef Foundation, Reef Energy, and Coral Colors. Corals have become much more vibrant except I had a Candy Cane die and a Duncan that is not doing too well. I had added them into the tank about a month after starting the Red Sea products.

Other corals like monti's, hammer, frog spawn, leather, stunner chalice, mushrooms, war coral, and zoa's are doing great.

Since I started using Red Sea, my tank metrics have stabilized with the exception of Alk - started at about 8 and is now down to about 6.

What is considered a good range for Alk in a reef tank? If 6 is too low, how can I raise Alk without causing the other metrics to go out of whack.

Here's the current set-up and metrics:

6
5 gallon DT
10 gallon refugium
Make my own RO/DI water
10% water changes weekly
Lighting (I know not the greatest but it is what it is)
Current Orbit Pro Marine (48")
ATI T5 Blue Plus
ATI T5 Purple Plus

I've been using a doser so additives are dosed daily. Only exception is the Red Sea Magnesium (Foundation C). For that, I am adding on a weekly basis.

Salinity - 1.026
Temp range - 79-82
PH - 8.3
Calcium - 450
Magnesium - 1400
Phosphate, Ammonia, Nitrite - 0
Nitrate - 2

Alkalinity is currently at 6 - Since I switched to Red Sea, I have been testing weekly so here is the downward progression. I had thought maybe the Alk test kit was bad (also Red Sea) so last week, I ordered a new one - also Red Sea.
9
9
9
10
8
8
8
8
7
7
7
8
7
8
6

Any advice?
Could the downward trend have contributed to the Duncan/Candy Cane issues?

Thanks!
 

jason2459

Premium Member
This is a good reference for acceptable ranges

http://www.reefkeeping.com/issues/2004-05/rhf/index.php

Alk between 7-11.

If you keep nitrates and phosphates to extreme lows (ie. Undetectable by your test kits) its generally advisable to keep alk under 8.

If your pH is generally high then I'd also keep the alk lower to mid range. If pH is generally very low I'd target mid to high in that range.
 

Astroreefer

New member
You can raise your alk using Sodium Carbonate/Soda Ash (Baked Baking Soda), it'll initially raise your pH a bit but will return to normal. As others have mentioned you might want to raise your alk to at least 7dkh.
 

Tanthaitrung

New member
If you keep nitrates and phosphates to extreme lows (ie. Undetectable by your test kits) its generally advisable to keep alk under 8.

If your pH is generally high then I'd also keep the alk lower to mid range. If pH is generally very low I'd target mid to high in that range.
Could please explain keeping low alk with extreme low NO3, PO4?

My NO3, PO4 are undetectable but alk is 11. My LPS and soft look happy.

I'm here in Vietnam, there is no choice, must use Red Sea Pro salt, that has high alk. I can keep alk around 8, but I want to keep the alk stable, so I set my alk is same range as the salt

Thanks in advance
 

jason2459

Premium Member
Could please explain keeping low alk with extreme low NO3, PO4?

My NO3, PO4 are undetectable but alk is 11. My LPS and soft look happy.

I'm here in Vietnam, there is no choice, must use Red Sea Pro salt, that has high alk. I can keep alk around 8, but I want to keep the alk stable, so I set my alk is same range as the salt

Thanks in advance

Those were just some general guidelines.


It is generally those that keep sps that they notice burnt tips or bleaching if the nutrients are extremely low and alk is in the higher end of the range.

My nitrates are generally under 5 and PO4 ranges .02-.08. My alk is usually around 10. I like a mixed reef myself.
 

Tanthaitrung

New member
Those were just some general guidelines.


It is generally those that keep sps that they notice burnt tips or bleaching if the nutrients are extremely low and alk is in the higher end of the range.

My nitrates are generally under 5 and PO4 ranges .02-.08. My alk is usually around 10. I like a mixed reef myself.
Thanks for your reply
 

Ron Reefman

New member
You can raise your alk using Sodium Carbonate/Soda Ash (Baked Baking Soda), it'll initially raise your pH a bit but will return to normal. As others have mentioned you might want to raise your alk to at least 7dkh.

The OP's pH is already at 8.3, so why bake the baking soda? You are just making work for no reason.

To the OP, just get some pure baking soda and mix a cup of it with RO/DI water and use it with some of your top off water (assuming manual top off). There is a good reef calculator that can tell you exact amount of most alk increasing mixes.
 

Astroreefer

New member
The OP's pH is already at 8.3, so why bake the baking soda? You are just making work for no reason.

To the OP, just get some pure baking soda and mix a cup of it with RO/DI water and use it with some of your top off water (assuming manual top off). There is a good reef calculator that can tell you exact amount of most alk increasing mixes.
You're right, it would be easier using straight Baking Soda, but it has a temporary lowering effect in the pH. that most find undesirable, but since OP pH. is already at 8.3 It might not be a concern. Another benefit of using Sodium Carbonate over Sodium Bicarbonate is that it is much more potent at raising alkalinity.

Sent from my LG-H955 using Tapatalk
 

Ron Reefman

New member
You're right, it would be easier using straight Baking Soda, but it has a temporary lowering effect in the pH. that most find undesirable, but since OP pH. is already at 8.3 It might not be a concern. Another benefit of using Sodium Carbonate over Sodium Bicarbonate is that it is much more potent at raising alkalinity.

Sent from my LG-H955 using Tapatalk

Baking soda does not lower pH, at least not in my experience. Soda ash (sodium carbonate) does raise pH, but it's very much a short term, temporary thing unless you are dosing it regularly. I did it for a long time with a dosing pump that spread out the daily dose evenly over 24 hours, so it added a single drip about every 45 seconds. Besides, pH is not a parameter you should be chasing. Unless something is very wrong in your tank, pH will always be in an acceptable (to me) range from 7.8 to 8.2.

BTW, love your avatar. I'm scheduling a trip to the Dry Tortugas (70 miles west of Key West, Florida). It's a state park with limited overnight camping, no beach fires and VERY little light pollution at all. I just hope the sky is clear so I can see the Milky Way.
 

pisanoal

Premium Member
Your alk dropped and the salt is no longer able to keep up on weekly water changes because your corals are starting to grow. I would switch out on of your other additives off the dosing pump and add an alk supplement to a dosing pump and dose several times per day. Adjust dose to maintain somewhere around an 8 alk.

Alkalinity is the most important thing to dose with a dosing pump if you can, or some other method that doses throughout the day. Especially if you have a lot of stony corals that are growing well, alk can drop significantly over a day's time, and a lot things are most sensitive to alkalinity swings. Since alk is most likely to have the greatest swings over the course of a day, and the most likely to cause issues on a swing, it is highly advisable to dose it constantly.
 

Timfish

Timfish
Premium Member
Everybody's got their numbers. But don't expect your corals to listen! :lmao: In this system alkalinity has always tended to run low but recently it's dropped down to 3.5 dKH (I've triple checked with two different API and a Hanna, to get better accuracy with the API I used 10 ml then divided by 2). Besides seeing other systems apparently do fine at low numbers Nikko Reef in Palau surprised everybody with 5.5 dKH.

 
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