Lighting Gurus (or is that Guri) Help me pick a new bulb, please?

[dakota9]

I need a new bulb for my single ended 250 wat MH.

I think the one on it is 10000K, and it gives my tank an ever so slightly green glow (all the natural sunlight I'm getting isn't helping either.

I'd like a 20000K bulb, but my clam chose to attach to the bottom of the tank when I first put him in to acclimate and so I need to consider par value as well. I'm looking for something in the 14000K to 15000K range as hopefully a compromise.

I also need to be cost concious as well, so the perfect bulb that costs $100.00 wouldn't be so perfect.

Does anyone have any suggestions on which bulb and where to purchase it?

Thanks in advance.

Does anyone have any suggestions

 

[jetchris]

why not go with a 14 or 15k bulb. I am using xm250 15k.

 

[dannybradley]

14k and 15k bulbs have really do have awful PAR ratings compared to 10k and 20k. 20k will have less than 10k, but higher than 14k. I've tested PAR inches below the water on a 400w 14k and read 20 PAR. A good 20K will give you a crisp white/blue. 15k and 14k are way too blue for me.

Aquamedic makes my favorite 20k bulb, but I've only run them as HQI, not mogul.

 

[dakota9]

Danny, you've confused me.......

20,000K's actually have more PAR than the 14k and 15k bulbs, but less than the 10,000k?

I like the crisp light of a 20K, so if its going to give me more par, then I should go with a 20K, as 10K's are out of the question at this point...

 

[mufret]

Dakota, which ballast are you going to run the bulbs on? The type of ballast you have will make a difference as to the bulb that's best suited for you setup/taste.

 

[dakota9]

Good question! Its an Ice Cap Ballast, not sure of the number though, I'll have to ask Tony, he sold it to me. Thanks Mike

 

[mufret]

Dakota, how old is the bulb that you are currently running? A 10k bulb should have a whitish light but an older bulb whose colors have "shifted" will usually shift to a green/yellow tint. I just wanted to mention that so you don't totally discount getting another 10k bulb.

Here is a listing of some bulbs tested on an IceCap 250w ballast:

 

[dakota9]

Thanks Mike!

I bought the fixture used, the bulb does have a yellow tint.

I'm still not certain which K rating to go with......

I'll check that link.

 

[mufret]

Dakota, unfortunately, it's a very personal decision! Do you like a whiter tank or would you rather have a more blue look? The K rating will influence a couple of things. PAR (PPFD) and personal preference. To throw another wrinkle into your decision, don't just look at the kelvin rating assigned by the manufacturer. Do a little research on the bulbs you are considering to see what others are saying.

 

[dakota9]

I like the blue white appearance, but would rather not see my clam wether and die on the sand bed for lack of PAR at the bottom of my 25 inch deep tank (thats where he attached during the first step of acclimation)

Because of that, I'm just tryiong to find a comprimise. I'm hoping Danny enlightens me more on his suggestions above.....

Thanks Mike and others.....

 

[blind1993]

dakota you can remove a clam from being attached, by putting an ice cube on the foot, but i would not reccomend it.(i read this in an article).

 

[james s_]

Go with 10k's and some T5 or VHO Actinics.Cant beat that combination for Par.I like the Ushio 10k bulbs.Nice clean white light.

 

[FutureInterest]

I don't think I generally agree with the assertion that 20k would have better par ratings than a 14k. It just doesn't compute! Anyways here's a lil link that will give you a better idea at the coloration of some different bulbs in a side by side comparison.

http://www.chrismorris.ca/250wcolour/">http://www.chrismorris.ca/250wcolour/</a>


g'luck

 

[jmaneyapanda]

Danny is right. There is no hard and fast rule about lower K = more PAR. Certain 20K bulbs do have higher Par than comparative lower K. Definitely not the rule, but there are exceptions (ie- Radium 400 watt 20K have enormous PAR) But, here's the rub- bulbs are going to only be as good/predicatble as the ballast and reflector they are used with. Any weakness in any of the three, and the PAR will suffer. Like legs of a tripod, it wont work unless all three are stable. That link Mike gave you is probably one of the best in terms of comparisons. At any rate, as Mike said, it will ultimately be your preference. If you like the look of a 20K, buy a goy byulb and reflector (your ballast is already top notch), and you'll be fine.

BTW- PLEASE DONT move the clam in the method blind suggested. There is a relatively easy way of moving a clam, but if you happy where it is, just leave it. He's obviously happy there also.

 

[blind1993]

jmaney i did not suggest using that method, i just told him that it exists also i stated i do not recommend doing that.

 

[jmaneyapanda]

blind1993;101446 wrote: jmaney i did not suggest using that method, i just told him that it exists also i stated i do not recommend doing that.

Im not trying to pick on you or anything. Its just that it was a bad thing to suggest, in my opinion.

 

[FutureInterest]

Danny did not say there are no hard and fast rules that a lower k has more par he said:

DannyBradley;101343 wrote: 14k and 15k bulbs have really do have awful PAR ratings compared to 10k and 20k. 20k will have less than 10k, but higher than 14k.

The words you put in his mouth though are fine with me and the data Mike posted backs that up.

 

[jmaneyapanda]

FutureInterest;101449 wrote: Danny did not say there are no hard and fast rules that a lower k has more par he said:



The words you put in his mouth though are fine with me and the data Mike posted backs that up.

Jin< is this towrads what I wrote? I wasnt trying to put words in anyones mouth. Maybe I didnt really read throroughly or understand Dannys post. If he was saying that ALL 20Ks have higher PAR, then I disagree.

Am I on the same page?

 

[dannybradley]

If we argue every specific bulb here we won't get anything decided on. This is especially true for someone who knows less about lighting.

GENERALLY speaking, 20k bulbs will yield a higher PAR rating than 14k and 15k bulbs. I've seen in many cases coral not do well under 14k bulbs that had been doing great under 20k bulbs. Switching back after several months made the coral turn back around when no other husbandry techniques changed.

The 10k with actinic flourescent supplementation is still my favorite look.

 

[linda lee]

Dakota9;101404 wrote: ....would rather not see my clam wether and die on the sand bed for lack of PAR at the bottom of my 25 inch deep tank (thats where he attached during the first step of acclimation)

I don't know anything about clams, but would like to eventually get one. I'm just curious: if you change the lighting and the clam is not happy where he is, can't he just move on his own like an anemone does to find a better *happy place*?