More lighting help required.

[Anonymous]

I have spent a coupla hours searching here and am now more confused than when I started. Its time for replacing at least my T5 tubes (1 year old) and possibly my MHs (Around 8 months old) and I need some advice!
(385GA mixed reef tank, with very few SPS but 2 clams and fair amount of LPS)

I think that the gradual deterioration of my lights is possibly partially responsible for the progressive appearance of derbesia of late in my tank. Anyway, the T5s are due for replacing and I dont really like the colour of the MHs- too yellow and want to change it. My tank, and its inhabitants look better and healthier under just the T5s, 2 white and 2 blue (No idea what K rating, the tubes dont say) than with the MHs included. I am viewing the MHs as a necessary evil as I have the clams.

Correct me if I am being simplistic here (Like usual) but 10000K MHs should provide a more white look than the 6500K (I believe) Aquamedic bulbs I hate so much at present. (colour- not manufacturer).

Also, If someone could chime in with something intelligent about what K white and blue T5s to run in conjunction with this I would really appreciate it. Bear in mind that I live in the 3rd world so most 'specific manufacturer' advice is useless to me. (We take what we can get usually although AM and Deltec are well represented here) I am more interested in K rating of the lights wrt to health and aesthetics of my system. (I know from the outset that this is a subjective topic and apologise in advance!)

 

[Anonymous]

Hi Andy-
I can't answer all your questions, but I'll take a stab at a few:

I think that the gradual deterioration of my lights is possibly partially responsible for the progressive appearance of derbesia of late in my tank.

That's very possible. As (most/all?) bulbs degrade over time, their spectrum shifts towards the lower end (towards lower K values). This is the kind of light that algaes prefer.

Correct me if I am being simplistic here (Like usual) but 10000K MHs should provide a more white look than the 6500K (I believe) Aquamedic bulbs I hate so much at present. (colour- not manufacturer).

10000K will be much whiter than 6500K. Actually, 6500K is very yellow (too yellow for most). It is good for coral growth, but not great for brining out their colors. I'm using two 14000K on my tank, which are a whitish-blue.

Also, If someone could chime in with something intelligent about what K white and blue T5s to run in conjunction with this I would really appreciate it.

I think you'd be happy with 10000K or 14000K MHs, and then maybe all actinic T5s. But it depends on what proportion of your total light is coming from the T5s.

How many and what wattage MHs and T5s do you have now?

 

[Anonymous]

JohnHenry, thanks for the prompt answer. I have 2 deltec T5 units, 5 ft long , one with white T5s and the other with blue T5s, two tubes each. I use a fairly short photoperiod on my 2 Aquamedic 250w MHs as heat is an issue, even with recently installed aircon. I really like the look of the tank with both sets of T5s on, and me and the corals hate the halides- only the algae seems to like it! I would like to stay with 2 white and 2 blue T5s as they are on timer for staggered lights up/down. In your opinion, what K rating should I be using?

 

[Anonymous]

I was considering 2 250w 14000K MHs (Or 10000K if its likely to make the tank too blue) along with 2 10000K (as white?) T5s and 2 20000K (as Blue?) T5s....your thoughts?

 

[Anonymous]

Happy to be of service. I've noticed we're two of the only RDO members generally up at this hour. 8)

It sounds to me like you'd do well to replace your MHs with either 10000K or 14000K. Then continue with the blue/white T5 mix. I'd say look for 10000K T5s for the white, and "actinic" for the blue. It's the actinics that really make corals flouresce.

Having said that, I don't use T5s myself, so am not sure if they're generally labled with K ratings.

I'd continue to run your MHs for a few hours, though, as your clams propably need the extra intense light. Also, when you replace the MHs with new bulbs, they should contribute less to the the algae problem.

Lastly, there is quite a bit of variation in how different K MH bulbs by different manufacturers appear to the eyes. That is, one company's 10000K may look much whiter than another's. If possible, see them in use at an LFS before buying. I love the color of my Phoneix 14000Ks.

 

[Anonymous]

Noticed that too JH, its 12H45 here in sunny SA atm

I will try and preview the 14K Mhs at the LFS, sounds like thats the answer for me.

A quick online seach of my LFS implies they only have 10 and 20000K 250w De bulbs (Aqualine). (http://www.northlandspets.co.za/product.asp?ID=556) I will see what they can get me. Also it looks like the T5s available are the aquamedics and they dont have a k rating, they are just catagorised as 'oceanwhite' and 'oceanblue'... aha, the joys of living with lack of choice!

 

[Anonymous]

Andy, IMO you should go for the 10K MH bulbs. Going from 6.5 to 20 would be a very big jump (down in terms of light intensity) and might not make the coral too happy initially, though might be a less of shock than going the other way (I believe - others may have views). Also, visually, from your pov, it would look very blue.

 

[Anonymous]

Thanks Tom, I was not considering the 20000K globes- because they would be too blue, I would like to see the effect of 14000K globes before I decide, IF I can get them here, otherwise its the 10000K.