PDA

View Full Version : Halide question



Kioti
01-01-2008, 10:09 PM
Hey guys. I have someone who offered me a 250w halide but I'm not sure if it's a good deal. It's my first tank and the light had been used for 6 months but they said they would give me another 6 month warranty with it.

Also I'm not sure what other numbers mean with lights...such as the 10000k and such. Oh, and my tank is a 28g bowfront with anemones. Thanks!

ReefJerk
01-01-2008, 10:32 PM
Is this for a bulb or fixture?

SpaceOps
01-02-2008, 12:11 AM
Since you only have 3 posts now, I went back and looked at your previous posts. If you really don't know much about salt (and it looks like you're new to the hobby), I would recommend first that you read everything you can about it. Start with Anthony Calfo's Conscientious Aquarist book, as well as every book you can find on marine aquariums. There are a ton in the library too. You can also find a mountain of information on the Internet. Wetwebmedia.com is the best I've seen. Thescmas.com, Reefcentral.com, and others are also great.

It's definitely a great hobby and usually worth the headache, but the biggest mistake most newcomers make is to jump into the hobby with an open wallet and not enough knowledge to guide your choices. This is nothing like freshwater. You can't just buy a bunch of fish or other livestock and expect them all to get along together, much less survive in the conditions you may end up with in your tank--salinity, temp fluctuations, ammonias, nitrite, nitrate, pH, protein levels, etc. Pretty much everything about the hobby requires knowledge, patience, some specialized equipment, frequent monitoring, and sometimes deep pockets. You'll minimize your risk by learning all you can before buying anything new, whether it be equipment or livestock.

There are a lot of very experienced people in SCMAS who can help you out. On some subjects you'll get 10 opinions from 10 people, but on the subject of advising newbies they'll all tell you to learn all you can before going any farther. You'll save yourself a lot of headache and money.

As far as the halide, my advice would be to pass on it. It may/may not be a good deal, but you don't give details regarding what's included, the color temperature of the bulb (e.g., 10,000K), or the cost. A 250W halide over a 29G is considered by most as overkill, not only because of the excess amount of light, but also because it may lead to temperature control issues.

THEJRC
01-02-2008, 01:27 AM
250 over a 28 bow should be excellent!!! especially with the anenomes....

As far as the K or kelvin value it's easiest to think in yellow to blue, the lower the kelvin the more yellow the light the higher the more blue... shoot for 10,000 to 20,000 depending on how blue you want your tank to look. With lower kelvin bulbs your going to want to run actinics to increase the blues... I run dual 250 ushio 15,000's with two 54 watt actinics. For some reason the ushio's seem to burn more yellow than other bulbs so the actinics help a lot. If it's just a pendant your going to want a bluer bulb for sure, if the fixture has actinics you might look at whats in there (I assume 10k) along with the actinics for a while and then adjust when you change bulbs.

The average useful life (in reef world) of halide bulbs is 9-12 months so your going to want to change that bulb soon.... T5's are about 6 months with power compacts running around 9 months. if the fixture works and has ballast and you cant beat the price... figure in 80 bucks for a bulb and go with it!

DKone
01-02-2008, 02:24 AM
250W should be great over your 28g bow. Is this a 250W pendant or fixture ? make/model ? type/make of bulb it comes with, ballast etc ?

Rose Bubble Tip anemone's sure do love light; some web resources would go so far as to recommend at least 6-8 watts of light per-gallon for them. This figure alas never considers how "deep" an aquarium, water clarity and how high above the water the lights are positioned. With a 250w MH fixture/pendant you can certainly provide enough light for your desired anemone and position the light higher above the water to reduce any heating effect it may provide.

As has already been mentioned, you may want to consider a higher kelvin rated bulb, 15K/20K, depending on the look you want to achieve and if the MH fixture contains actinic bulbs or not. Temperature control could become an issue. Monitor the temperature (before you put the RBTA in there!) and if it swings too high, when the MH bulbs have been running for a few hours, then you will need to consider cooling options - from blowing air across the top of the tank with a fan, to small chillers. The Rose Bubble Tip Anenome prefers temperatures in the range of 72-80F, though when I kept mine I was towards the 78-80F end of this range. The important thing is consistency and trying to avoid large swings in temperature +/-.

I was focussing on the anemone part of what you has previous posted you wanted to keep in the tank, rather than the fish. The clownfish, being from the damsel family, are pretty hardy and tolerant of conditions not omptimal. The RBTA is somewhat hardy as anemones go. However, if the conditions in the tank are not to the RBTA's liking, from lighting, flow, temperature, substrate, etc.. it will constantly be crawling around the tank looking for a better location. If the anemone is on the move, you need to carefully watch out for it climbing into any powerhead intakes, overflows etc, and turning the anemone into sushi! (i've seen it happen!).

!!!Welcome to the SCMAS Forums!!!

Warm Regards,
John

THEJRC
01-02-2008, 02:34 AM
wow with my avatar the same I thought I doule posted.... hah

SpaceOps
01-02-2008, 09:51 AM
Agree with DKone that while it's not the most accurate method because it doesn't address tank depth or surface area dimensions vs. the number, wattage, and PAR of the bulbs used, the watts-per-gallon rule also depends on the type of anemone. Each has minimum/optimum/maximum lighting preferences.

Still, many of the experts on wetwebmedia.com (Fenner, Calfo, Pro, ...) recommend MH and between 4-6 watts/G; you have about 9. You'll see the occassional recommendation for higher even levels depending on the situation. A 175W MH comes in at 6.25W/G.

As far as higher Kelvin rated bulbs, they do have the big advantage of improving the overall look of the tank and even improving pigmentation.

You'll definitely never have a shortage of light with a 250W MH, and I suppose if you needed to you could put the 250W high enough so the anemone wouldn't be shocked by the sudden change (what do you use for lighting now?), and then slowly lower it over time until the anemone adjusts. You'll know if it's too much if the anemone moves to a sheltered location (or dances around and screams like it's "foot" is on fire). I think the cost of a 175 and 250 setup are close enough in cost that you can choose either of them, so the only other significant factors would be light intensity and heating.

Here's a great place to see what the pros recommend: http://www.wetwebmedia.com/marine/inverts/cnidaria/anthozoa/anemonelightngfaqs.htm
and follow the links near the top labeled Anemone Lighting 1, 2, 3 ...