Alkalinity......a mysteries ???

machodik

New member
Dear All,

I wonder what should be the right Alkalinity for a better SPS + LPS tank?

1) 7.7 ~ 8 dkh as the natural sea water
2) 10 ~ 12 dkh

But I have seen some good tank plays around 6~6.4 dkh (the Tank of the month ,this January 2015)

cheers,


MD
 

tehachappi32

New member
It is hard to get alk low at 6.4 right? I don't know about huge tanks but for small tanks like under 100 gallons, every time we change water, the alk spike is not very good for corals....
 

machodik

New member
JANUARY TANK OF THE MONTH (http://reefkeeping.com/joomla/index.php/current-issue/article/153-tank-of-the-month)....Alex costa's tanks parameter:

Water Parameters: •Specific Gravity: 1.026 Soma optical refractometer
•pH: not measured
•Calcium: 430-450 ppm by Salifert test kit
•Alkalinity: 6-6.4 dKH via Hanna Digital calorimeter
•Magnesium: 1200-1300 ppm via Elos test kit
•Phosphate: Not measured for the past two years. Prior to that it was undetectable
•Nitrate: Not measured for the past two years. Prior to that undectable
•Temperature: 26-27˚C (79-81˚F) via RKL & American Pinpoint


he got a nice good color corals on it. how he do it?
 

rgulrich

greybeard
This article may be of some help:
http://www.advancedaquarist.com/2014/7/corals

A quote: "Aquarist most often maintain elevated levels of pH, alkalinity, and calcium to promote coral health. In this study however, elevated conditions of these parameters resulted in a decline of photosynthetic efficiency (Fv/Fm), indicating an overall decrease in coral health. There was also a slight decrease in health as parameter values increased within the recommended ranges. This effect should be considered when dosing in a closed system as corals experienced optimal health within the lower values of the recommended ranges."

Hope this helps.

Cheers,
Ray
 

bertoni

Premium Member
There are a lot of factors involved in coral growth and calcium carbonate solubility, both of which play into how well corals grow. Given the limits of hobbyist testing equipment and our ability to control all the parameters involved, trying to find an optimal level is going to be very difficult. There are some studies (as already noted) that increasing the calcium and alkalinity levels can encourage growth. That said, growth isn't our only goal. Personally, I suspect that 7-11 dKH, the usual recommended range, is going to be close enough to optimal for most tanks, although carbon dosing sometimes seems to make higher levels in that range problematic.

Coral coloration probably is of more interest, relatively, than absolute growth, and it's less well understood.
 

machodik

New member
Thanks for your kind advise, my experience is that KH higher than 8 dkh tends to cause STN and browning. I have been struggle this lately and until now still unable to fine tune my calcium reactor to maintain between 7.70 to 8 dkh since I have a very low nutrient (no3 : 0 , Po4 : 0.03 to 0.08) due to my Biopellet reactor .

I have change my salt from Red Sea coral pro to just normal Red Sea salt. But still sometimes my calcium reactor will increase the KH to even 10 dkh as the consumption is not much because I only got some frag in my tank.

I attached a photos of my corals that I don't know if the browning and STN (already control) was due to Kh or lightning ;

2a9b9b91858abb62e007c9a02e3a1b72.jpg


553f811331aae5a2150703c2f8ca70af.jpg


Both coral where place on the highest point of my tank.

df1ce6283aba60224a7ac12354f95b19.jpg



Cheers,

MD
 

Bilk

New member
Perhaps taking the CA reactor off-line and simply dosing either kalkwasser or 2 part is the better option for now. You have very little demand for calcium and alkalinity at this point. Maybe just water changes will work as well until you have more corals that could utilize the output of the reactor.
 

machodik

New member
I have maintain for 2 days at 9 dkh and I stop the calcium reactor until the KH drop to 7.70 dkh then I will turn on the reactor to see if I can maintain at this level. If still not then I will off line the reactor and instead dosing with 2 parts .
 

Bilk

New member
I have maintain for 2 days at 9 dkh and I stop the calcium reactor until the KH drop to 7.70 dkh then I will turn on the reactor to see if I can maintain at this level. If still not then I will off line the reactor and instead dosing with 2 parts .
That sounds like a good idea and you may actually be able to just do water changes for now instead of dosing. Good luck!
 

machodik

New member
Thanks for your very supportive words. Crossing my finger and hoping I will succeed with this fine tuning !
 

tmz

ReefKeeping Mag staff
Premium Member
This article may be of some help:
http://www.advancedaquarist.com/2014/7/corals

A quote: "Aquarist most often maintain elevated levels of pH, alkalinity, and calcium to promote coral health. In this study however, elevated conditions of these parameters resulted in a decline of photosynthetic efficiency (Fv/Fm), indicating an overall decrease in coral health. There was also a slight decrease in health as parameter values increased within the recommended ranges. This effect should be considered when dosing in a closed system as corals experienced optimal health within the lower values of the recommended ranges."

Hope this helps.

Thanks for the link.



Cheers,
Ray

The article cites variable zooxanthelae growth as a meareable indicator related to alk, calcium and pH. Assuming the measures are correct I'm still not sure lzooxanthelae density is as relavant as skeletal growth. Don't think it is.
It also deals in some extreme conditions( I consider 7meq/l/ 19.6 alk and 1.5meq/l / 4.2 dkh extreme . I wonder if 20dkh it could even be maintained without precipitation). Looking at graphs it's interesting that there is very little difernce between 2.5 alk and 11dkh. Seems to confirm the 7 to 11 dkh range generally cited and noted by Jonathan. Calcium and pH also fall in recommended ranges .

For me 9 dkh with calcium 450ppm and pH 8.15 to 8.35 daily swing works very well.
 

tmz

ReefKeeping Mag staff
Premium Member
I feed heavily. NO3 is 0.2 ppm up to 0.5ppm. PO4 stays between 0.02 ppm and 0.04ppm per hanah 713 colorimeter with very rare 0.05/.06ppm PO4 readings. I tested daily for years ;now it's once a week since they don't change very much.
 

machodik

New member
I feed heavily. NO3 is 0.2 ppm up to 0.5ppm. PO4 stays between 0.02 ppm and 0.04ppm per hanah 713 colorimeter with very rare 0.05/.06ppm PO4 readings. I tested daily for years ;now it's once a week since they don't change very much.

I also have a very low nutrient but I observed that my Alk goes beyong 9 dkh , STN certainly observed.

I am trying to maintain my calcium reacotre to provide me at 7.7 to 8.5 dkh, I think that will be good for my tank . my calcium remained at 420 to 450 ppm and mg at 1400 to 1440 ppm. only KH is really difficult to maintain.
 

machodik

New member
Dear All,

I have observed that my PH level will be much higher when my KH is much lower specially at night . Is this can be a conclusion that by looking at the PH level of my apex fusion will somehow give us a hint about the range of our KH? I am looking at some possibility to at least determine my KH level in a day thru the apex fusion dashboard specially when I am not at home .

Any opinion ?
 

Randy Holmes-Farley

Reef Chemist
Premium Member
As I mentioned in the other thread, the change in pH day to night is not reflecting the consumption of alkalinity, but rather the consumption and production of CO2 by photosynthesis and respiration.

If you did track alkalinity consumption day to night, you might find it a bit higher during the day, but there have been mixed reports on this.
 

tmz

ReefKeeping Mag staff
Premium Member
^ I agree. PH variations don't give a view of alkalinity consumption;they do indicate CO2 levels,IME.
 
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