coral questions

[cmoreash]

I have been doing more coral research, and have come across some new questions.  What is the difference between pH and alkalinity?  What should these be at for corals, and how to adjust them?

 

Oh yea, and how you you guys propagate new corals, and put them on rocks?

 

Um......I think that's it for now...  

 

Oh wait, what is the real different between soft and hard coral, and do they need special supplements/foods?

 

(Edited by cmoreash at 2:34 pm on May 24, 2002)

[Paul G]

Hi

 

I'm no expert so any body feel free to correct me, but as I understand it pH is the amount of hydrogen ions in the water and alkalinity is the waters capacity to buffer against pH dropping - if it's too low then pH could be adversely affected.

 

Natural seawater has an alkalinity I believe of around 7-8dKH or 2.5-2.9 meq/L

 

These figures are assuming a specific gravity of 1.025.

 

pH I think generally should be around 8.3

 

Also I understand it's important that Calcium and alkalinity should be balanced if using additives or testing your existing water.

 

Buffers are available for increasing pH and alkalinity but as always care should be taken. Sodium bicarbonate increases alkalinity also.

 

As for propagating corals it depends on the type but sps corals can be cut of with clean wire cutters etc (some can just be snapped off) and glued with reef safe epoxy e.g Milliput, devcon etc

 

Softies - elastic bands, superglue gel, cocktail sticks

 

As for soft and hard corals, you would get a better answer from a good book, and supplements and foods can vary between species and hobbiests preferences. It's probably better to decide what you want to keep  and then research whether you can cater for its needs.

 

As I've said this is my simplified interpretation, so the more research -  as you are doing - the better.

 

HTH

[Leonard]

pH is the measure of H+ ions in solution, and is rated in a scale range of 0-14, 7 being neutral.  The lower the pH, the more acidic the solution is (pH is a negative logarithm)  pOH is the measure of OH- ions.

 

Alkalinity is the measure of acid neutralizing compounds in equalibrium.  The single most pervasive acid neutralizer is carbonates, and therefore alkanity is often used interchangably with carbonate hardness.  Alkalinity, as Paul stated, will buffer pH from going more acidic.

 

There are far too many methods to control pH and alkalinity to describe, but it's noteworthy to mention that in a properally set-up reef tank, their values are usually pretty stable and similiar to NSW.  Various buffers (ie carbonate buffers) and calcium solutions are commonly used to achieve the desirable levels if need be (pH of 7.9-8.4, alk 8-12 dKH).

 

The "real" (ie, techinical difference) between soft and hard corals is the former are octocorallians, and the latter are hexacorallians.  Octocorals, simplified, possess multiples of 8 tentacles, whereas hexcorals possess multiples of 6.  Of course, in laymen's terms, soft corals are those that generally have soft bodies with no solid skeletal backbone, whereas hard corals lay down a calcium carbonate skeleton for support.

 

Its my longstanding opinion that corals need not be fed anything intentionally.  Phytoplankton is a nice nutritional supplement.  In terms of elements necessary for coral health, most are provided by the foods you feed your fish.  Other shortcomings (especially calcium) can be made up with 2 part solutions (B-ionic, C-balance, etc.) and calcium additives (kalkwasswer is my Ca additive of choice).

 

Regarding propgation, I'm sure you'll get plenty of answers from this community, so I'll skip it for now.

[cmoreash]

i should have the gravity, or salinity, whatever it's called at 1.025?  huh, i thought It was supposed to be 1.023.........So what would I increase the pH and alkalinity to if needed?

[Leonard]

The salinity of NSW is 35ppt.  At 79-83 degrees, that equates to a specific gravity of about 1.024/1.025.  That would be my target range.

 

As I stated, pH will shift throughout the day.  Ideal range is between 7.9-8.4, but small deviations from these numbers are just fine.  Alk between 8-12 dkH is ideal, although most reef tanks have figures below this.  If it's above 5, I tend to not worry too much.  I cringe when I hear hobbyist trying to hit target numbers even though everything is doing great.  My advice to let your animals tell you if things are fine.