15k or 20k sps yeilding growth

[ryansreef_26]

Hi I currently have 2, 15k MH XM 250w bulbs lighting my reef tank along with 4x54w h.o. t-5's I am keeping sps corals mostly acro's i noticed the growth rate is slow and colors are pale, could this be due to the 15k spectrum, i am due for new bulbs soon I am going to go with the 20k can this make all the difference in growth and color when all my water parameters are right on?

144-gallon, wet/dry, MRC skimmer, GFO, ROX carbon c-balance 2 part, and dosing of kalk, Ca-450-ALK-9dhk- pH- 8.3- Mg- 1450- pO4- 0.05 Nitrate-0 Ammonia-0 Nitrite-0,

lighting- 716w total, 2x250w MH 15k, 4x t-5 54w each.

 

[sirreal63]

The 15K XM is one of the lowest par 250 watt bulbs, you will gain a little par from the 20K XM's or you could switch to a 14K and get more par. I assumed mogul socket, what ballast are you running?

 

[JAustin]

I agree with sirreal63. The XM15K is a very low par bulb. Most 20K bulbs will out perform that 15K bulb. What t-5s do you have (brand and name) in what fixture and what pendants are you running for the halides?

going with a higher K doesn't mean you'll get slower growth all the time. A good 20K bulb with higher wattage will grow coral like a 10K of lesser wattage. In most of my SPS reefs i've ran 400W 20K halides to do just that. Now i'm running a 50g tank so the 2 250w 20K ushios are going to be fine.

What's your tank depth?

Cheers
Jason

 

[JP SPS]

I saw someone mention ballast brand. Does the brand of ballast make a difference?

 

[sirreal63]

Brand to a lesser degree, the type of ballast can make a lot of difference.

 

[ryansreef_26]

I have 2 Lumatek dimable ballasts, and they are double ended bulbs, on an obysea lighting fixture. For the t-5's i have 4 blue bulbs-ZooMed brand not the original bulbs. I usually run the bulbs on superlumens setting on the ballasts, recently I dimmed them down to 175w, the spectrum looks more blue and the polyps are comming back out on my acro's.

 

[cpllongjk]

I used to tun Phoenix 14k double ended bulbs when I had a 250w medal halide. Its a great bulb with decent par and good color. IMO the phoenix bulb looks like a lot of 20k bulbs.

 

[ryansreef_26]

Im considering going with the 14k now but i really like the deep blue the xm20k gives out, so what would be the best choice here? and i was also thinking of just scrapping this whole double ended fixture and just buying the single ended bulbs n the housing for it since they are only a few $ extra, i want to do it right to keep my sps thriving, my tank is 36" deep i have lps corals on the bottom of the sand all around it which seem to be doing fine, i keep all my acros in the middle and top of the tank, would it be better to just use a single ended bulb and housing instead of this double ended fixture?

 

[sirreal63]

If I understand you, it is an Odyssea fixture that you swapped out the ballasts for, and are running an XDE15k, one of the lowest par bulbs available, and you are under driving to 175 watts, just to get a more blue color? Is the tank 36" deep or 36" tall?

 

[Guygettnby]

i have the same fixture as you right now. i have changed things around, but i use pheonix 14k bulbs. the last 3 tanks i have owned had the same pheonix bulb. i love the look, wich is more of a 18-20k look with great par. my tanks have always loved them and i love the looks.

there is nothing wrong with a double ended setup.

 

[ryansreef_26]

Sirreal63- yeah thats all correct, tank is 36" tall/deep. its the 144g oceanic half circle tank.

 

[ryansreef_26]

So my question is now should what bulb do you recommend for the best par/ growth for my sps corals can i get for this current fixture, or should i just go single ended 250w?

 

[sirreal63]

Go with the Phoenix and I would stay with the DE and run the ballast on the superlumens setting, it is as close as you can get to running the bulb correctly. If you want more blue then add ATI Blue+ bulbs until it is the color you want. To help you a little...depth is front to back, height is bottom to top. For a 36" tall tank, you want par to penetrate down, but also you want some spread, that is asking more of the Odyssea reflector than it can do. Use the Blue+ blbs to help add to the par and spread, which they will do, but again, it is asking a lot of the crappy Odyssea reflectors.

You will get significantly more par with the Phoenix 14k's so you may have to acclimate the sps to the higher par, this is normal, either add some fiberglass screen to the top of the tank, or run a shorter photo period, or both. Watch the corals, they will tell you if they are getting too strong of light.

 

[ryansreef_26]

ok, thank you, I will go with the pheonix 14k then, and i plan on adding all blue bulbs bc i really like the blue spectrum, thats why i was going to go with the xm 20k but if the pheonix is better par and almost as blue ill go with that. I didnt know about the depth and tall, lol thanks again yeah so the tank is 36" tall then. what do you mean by running the bulb correctly? what would be running the bulb correctly if its close on superlumens?

 

[sirreal63]

DE bulbs are meant to be run on HQI ballasts, which supply more than 250 watts to the bulb, and you want to run the bulb as close to spec as you can, the regular 250 watt setting will slightly under drive the bulb, causing a loss of par, which is what you do not want with a tall tank. Using the super lumen setting will drive the bulb closer to spec, you then use the T5's to supplement the color to your liking. The ATI Blue+ bulb will add the blue and still keep the par levels up, which is exactly what you want with the 36" tall tank.

 

[ryansreef_26]

thank you for clearing that up, im going to order all the bulbs today, ill post back when everything is in and running to let you know how the corals are doing.