View Full Version : kelvin temp ? t5

12/11/2011, 03:17 PM
I run a 6 bulb t5 retro fixture. I currently have 3 actinic+ which are 22000 kelvin and 3 aquablue + which are 15000 to the best of my knowledge.

My question is that puts me at an average kelvin temperature of 18500k

Im not seeing much growth from my mostly everything. I know that stems from a list of possible issues, but if the kelvin temp is too high should i be considering lowering it.

If u think i should lower it, how low and recommend a bulb. All my blues are on a timer and all the white lights are on a timer.

12/12/2011, 04:19 PM
no takers?

12/12/2011, 04:51 PM
I will start with this. The Aquablue bulbs aren't really 15k and using kelvin is a bad idea. Most Aquablue bulbs are closer to 10k than 15k. I would bet your setup is pretty white overall and probably closer to a 12-13k look with all lights on. 18k is pretty blue in this hobby.

Now, you should be getting pretty good growth with those lights. Colors may lack because of the aquablue bulbs but growth should be there. Tell us more about your system. What lighting system are you using? Is it a fixture or a retro fit setup? How old are the bulbs and are cooling them properly? How far off the water surface are the bulbs?

Next, tell us more about the tank. How big, how much flow, how much you feed and how much you dose? What are your parameters?

I think with that information we can start to check some items off the list. I highly doubt lighting is the culprit unless a sub-par T5 setup is being used and it isn't getting the light you need.

12/12/2011, 04:59 PM
You are basically running a 50/50 blue-white combination there, which is generally considered a good balance for growth & color. Growth rates can depend on a number of factors, especially the species you are keeping. Some grow like weeds, others very slowly. The main issue you want to be concerned with is the color and overall health of the specimens in the tank. If your corals are healthy (not losing tissue, dying, etc.) and maintaining their color it's generally safe to assume everything is fine.

12/12/2011, 06:51 PM
Thanks for the opinions, I know there are several factors that play into growth. I do pretty well with lps, but sps not growing. its still new to me as my oldest sps is about 6months old. I've seen growth from the simpler sps like birdsnest monti caps etc. but others dont seem to change at all. im getting good polyp extension on them and no tissue loss, just growing very slow.

I have great growth with some things others just dont seem to change.

as for the fixture itself its a 6x54w retro i built, phillips ballasts, slr reflectors all the bulbs are geissman. sits around 10 inches off the water, all cooled by a 4.5 inch fan which cranks fresh air into the canopy.

We could get into all the contributing factors, but i was just more interested on everyones thought with the bulb temps. I dont post alot but I read. Not looking to get into a great debate here.

thanks again

12/12/2011, 06:52 PM
can u check your phosphate levels,make sure there at 0 ppm,high p04 inhibits stony coral growth.soft corals usually grow at a fairly decent rate.remember rome wasnt built overnight,in this hobby patience is worth more than the investment itself.if your not doin so already get a good reef test kit and check all levels that apply,ie no3,p04,ca,mg,sg,yourlights sound pretty decent.id agree with the above around12-13k.

12/12/2011, 07:18 PM
oh yea i have a whole load full of tests, cal, alk, mag, nitrate, trite, amm, ph etc. Everything is in check and has been very stable this past year. The cal and alk have slipped down a little bit over the past 3 months, but still reasonable 8.5dkh and 380 cal. which im slowly bringing back up.

Havent invested in a hana meter yet for phos, but am thinking of doing so. I also am looking to buy a refractometer. I just dont trust the cheap plastic salt meter, when checked against a calibrated refractometer its always off a point or two.

12/12/2011, 07:21 PM
everything looks ok,it sounds like the dip in alk and ca may have been the issue,looks like things are on the upswing again,i use a glass hydrometer its about as acurate as the refractometers,but you cant go wrong getting yourself one of them toys to.goodluck.

12/12/2011, 08:02 PM
yeah i just hate to drop 100 dollars on testing tools when that money could go towards something else. Oh well once you have them you have them. Anyone able to recommend a good refractometer. I was looking at one on BRS, 40 dollars seems reasonable

12/12/2011, 08:14 PM
thats a good deal as ive seen them sell for upwards of $80.00 the glass hydrometers are only $20.00 and basically are as accurate.they come in a tall plastic tube and inside it has a glass float that self calibrates for temp.it just uses boyance and floats and has a greenzone 1.020-1.025 only downside is glass is fragile.

12/13/2011, 07:12 AM
can u check your phosphate levels,make sure there at 0 ppm,high p04 inhibits stony coral growth.

Actually this is a myth and not true.

Go check out Reef Builders. They put up an article about a recent study where it was found that some acros grow much faster in higher phosphate levels. That isn't to say that all SPS grow faster in the higher phosphate levels but to say the phosphate limits growth, isn't totally true.

Higher phosphate usually leads to dull brown corals.