Coral Growth Rate

[chatyak]

I am wondering why my corals are not growing faster. All of my parameters are great, and I dose two part daily. I have metal halide lighting, etc... I know corals do not grow THAT fast, but I haven't seen much growth at all... they are just baby frags. The only thing that grew was my green star polyps and that was only a tiny bit of a purple mat.

I have my halides (the bottom of the pendant) about 17 inches above the tank rim. Is this too high? Lights and info in my signature.

 

[svb57]

What kind of 15k DE lights do you have. I had 14K Phoenix over my 300g and changed them out to 14k Giesmann and had three times the growth. Mine are 6" above the water.

Jim Mc

 

[chatyak]

I have Hamilton 14K 175 watt bulbs in lumenbright retrofit reflectors... same ones here but not "finished".

http://reefkeeping.com/issues/2008-06/review/index.php


I went by the article and put them roughly 17 inches or so off the top of the tank. (bottom of pendant)

 

[heller792]

i thought the same, heres a link to my other forum with my growth comparisons
http://www.reef-face.co.uk/forum/index.php?showtopic=15795

Dave

 

[chatyak]

I am sorry I made a mistake. The bottom of the pendants is 14" off the black plastic brace from my tank. I just measured.

 

[chatyak]

<a href=showthread.php?s=&postid=15257254#post15257254 target=_blank>Originally posted</a> by heller792
i thought the same, heres a link to my other forum with my growth comparisons
http://www.reef-face.co.uk/forum/index.php?showtopic=15795

Dave

I wish my coral looked like that

 

[heller792]

if you want better growth then change to 10k lamps, they will provide the corals with more usable light.

Dave

 

[chatyak]

Could you provide a link to the reasoning for that Dave? I'm not negating your statement, just like to learn why.

 

[IndyReefMan]

Can you post your measured water parameters-- Alk, Ca, Mg, PO4, NO3?

 

[chatyak]

I can do that. I will take some tests this evening and post them.

 

[ludnix]

Have you been taking pictures to compare to? It might be hard to tell how much they have really grown if you have nothing to compare them to.

 

[luther1200]

Swithcing to a 10K lamp will give you more PAR and there fore more potential for growth. But many people report excellent growth with the bulbs you have. So I don't really think thats the main issue at hand.

But, how old are the bulbs? Were you getting good growth and it stopped, or it just never really took off?

 

[Mopar Reefer]

I suggest you lower your lights down to your tank around 6-9" from the water. This will help with growth

 

[chatyak]

Here are the test results:

Ca: 450
kDH: 9 (Elos) & 7.57 (Hagen)
Mg: 1550 (Elos)
N03: 0 or undectable
PO4: 0 or undectable


The bulbs are 4 months old? Around there somewhere.


I've taken a few pictures and I see a bit of growth (the white part of stony corals expanding) but it has never really taken off... just barely a few millimeters.

 

[saltjohnswharf]

Isn't 6500 Kelvin the best color for grow out tanks? 10,000 Kelvin with Actinics looks great and will give good growth. My fixture is 15" above the water and things grow quite nicely. FYI I am planning to lower the light this weekend to around 9" above. I am using 175 watt 10K lamps.

 

[chatyak]

I was reading that the reflector has a lot to do with the height the bulbs are placed at. How true is this? I suppose I could lower the lamps and see... time to build again... I have them fixtured to the ceiling

I see people's frogspawns and hammer coral colonies and they are big beach ball shapes... it would take mine 2000 years at this rate to get like that. What's the deal?

I've come a long way... now I just have to master the growth of coral.

 

[chatyak]

Also.... if actinics were used with 10K bulbs... would it detract from the 10K? Anotherwords... is 10K + T5's the same as using a 14K?

Or would the T5 mainly give a look to our eyes, while the 10K bulbs help with the growth "behind the scenes"?

 

[saltjohnswharf]

Those pendant reflectors have better flexibility than the others, which I call hotdog bun reflectors. My mistake was using a hotdog bun. Saved me a bit but the lighting is nowhere near as good. People with the same lights and ballasts with the round reflectors have far better light than I do. If I had to do it all over again I would buy: http://www.hellolights.com/index.asp?PageAction=VIEWPROD&ProdID=1515

 

[saltjohnswharf]

<a href=showthread.php?s=&postid=15259003#post15259003 target=_blank>Originally posted</a> by chatyak
Also.... if actinics were used with 10K bulbs... would it detract from the 10K? Anotherwords... is 10K + T5's the same as using a 14K?

Or would the T5 mainly give a look to our eyes, while the 10K bulbs help with the growth "behind the scenes"?

Detract no. What it does is just makes the light more "pleasing" to the eye. Using a 14K bulb you get the same effect. Using a 10K gives you more of that white light corals like. The actinics just makes it look softer. A PAR meter will show you that a 10K will give more light than a 14K.

 

[chatyak]

Hmm.. well I'm not going to go out and buy a PAR meter so I am going to take your word for it

I'll have to build a side+lid canopy to sit over the tank, with pegs on the sides to lower the light-board to different heights. How long should I wait on each height to see if it's doing better?