lighting question

[gomd]

Okay, I asked this in the Roanoke forum, but we seem to have problems talking to each other down here. My question is this. I have 3 xm 175watt 20000k metal halides running on my 125 reef tank. I've been looking at other peoples' tanks and seeing this incredible growth that I'm not getting. My water parameters are all ideal, I run kalk, I supplement, and the only thing that I can think of is that I need more light. I know that the 20000k doesn't put out as much energy as say a 10000k bulb would, so should I consider going with a different color temperature or should I supplement with some T5's or VHO's or both?
Any suggestions would be greatly appreciated. Also, I have a pink colt coral, a two headed torch coral, and a two headed metallic frogspawn that I'm trying to trade for some sps if anyone is interested. The torch is the only one that I'm going to want something of some good value for, I'll take frags for the others. Thanks!

 

[surfnvb7]

what kind of corals are you keeping in the tank mostly? if you are having a problem with sps, yeah 3x175's arent gonna cut it. better off with 250's any way you look at it with a tank that big.

 

[gomd]

Hmm, I went with 175's because Jeremy at Something Fishy told me that that was all I needed. I've moved to sps and I'm just not getting the kind of growth I'm seeing in other people's tanks.

 

[HOC]

There's really a lot more to coral growth than the color temp and wattage of your halide bulbs. You may get a little better growth out of a lower kelvin,higher wattage bulb, but if all your water parameters aren't right you still won't have much growth. Water temp, water flow, lighting cycles,nutrient load, proper elements in the water,food, and lots of other things will affect growth. IMO 175 halides can be enough light for some types of sps. It really depends on the species. The distance of the light from the water and the depth of the coral in the tank will also make a difference. I would check some of these other things before you spend the money on lighting. 175 is a little on the low side, but as I said it's enough for some (maybe even most in the right conditions) species.

Those xm 20k's are REALLY blue in 175 watt. The higher you go in wattage, the less blue they look. After some thinking, you might want to go to at least a 15k. If you got all the way to 10k you will definately need some actinic suppl.

 

[JC VT]

If you are concerned about lighting, you may want to look in to the XM 10k or the Iwasaki 15k. They will give you a pretty good boost in PAR.

 

[gomd]

Thanks for the replies. I've got growth, just not like I could have. I'm pretty anal retentive about my water conditions so that really isn't a problem. I also supplement. I'm just thinking that traditionally I haven't had stellar growth. I'm sure a lot of that is due was due to the age of my tank, but it's been running for almost three years now. I did start running kalk again recently and that seems to have made a huge difference in the happiness of everything in the tank. I'm also basing my lack of lighting theory on how slow my clams grow.

 

[CeaHorseMaShell]

I forgot to add that the corals near the top of the tank are growing pretty fast as compared to ones near the bottom which also points at a lighting problem.

 

[DJM28064212]

Well I dont know the par ratings, but the reeflux 12K bulbs are very pretty. They have a really nice tint of blue and I think it has more par then the 20k XM. My place lights up like a christmas tree when they are on. Just my 2 cents.
Doug

 

[manderx]

I'm pretty anal retentive about my water conditions so that really isn't a problem

'water quality' is a big, vague term though. there's more going on than just salinity/ph/nitrate/phosphate/calcium/alkalinity that most people test for. there are plenty of other elements/micronutrient that we don't have test kits for or even understand, plus the whole microbiological aspect that we are just beginning to try to understand and manipluate (vodka/zeo/....). at this point i think luck is still a pretty significant part of getting a tank *truly* in the zone.

i'm also using the reeflux12 bulbs and like them alot, but haven't had my 175s long enough to know if they'll do anything for growth (the 250 i had over a 30cube did ok). plus they are pretty cranky on magnetic ballasts. we had to run doug's on my icecaps for a few days to burn them in so that they would then fire reliably on his mag ballasts.

 

[gomd]

You make an excellent point. I was refering to high ammonia, nitrites, nitrates. I don't pretend to have anything but very general knowlege about what other elements need to be in the water. I do know that using kalk has made things happy, and I've tried supplementation with iodine, microvert, the two reef vitamin product from Kent that I can't for the life of me remember the names of, and strontium. I really haven't been able to tell a difference, although honestly it may just be that my tank wasn't mature enought for things to progress. I'm going to add some vho lighting soon, then when its time to replace bulbs again I'm going to switch to the XM 10Ks and see how that does.

 

[JC VT]

FWIW I have had the XM 10k and like them alot with VHO actinic.

 

[mbort]

How long of a time frame are you considering for this "slow growth"? And as Matt/Chris alluded to, "ideal water parameters" are not readily measureable (even with all the things we can measure). And even then, factors such as water flow, "ideal" amount of light, and numerous other things are going to be highly species dependent.

And yes, I do agree that 175 watt XM20ks are on the low side of light requirements for acros in general. Going to the XM 10ks will add a lot of light to the tank. I have also noticed significantly increased growth rates when using actinics vs. not using them, not sure why but that has been my general experience.