Coral Photoacclimation

[lossman]

Reading your article in the January Reefkeeping magazine. I would assume acclimation would also apply to changing your lighting setup. We are considering converting from our current PC/VHO combination to a T5 setup.

What would you recommend for this type of acclimation for corals we already have?

Thanks

[ATJ]

lossman,

I'm sorry for not replying earlier - the auto notification must be playing up again. :confused:

I would recommend doing acclimation if you think the light reaching the corals is going to double or more.

If you have multiple rows of T5 tubes that can be switched independently, it will be quite easy to acclimate. Start with as many tubes to provide the equivalent light to the PC/VHO and then gradually add the other tubes over a few weeks.

How many tubes/lamps do you have now and what size are they? What are you planning on replacing them with?

[lossman]

We currently have 400 watts of PC lighting and 640 watts of VHO on our 150 gallon tank. Let me know if you need more details.

We wanted to up the lighting to increase our coral keeping potential, such as for Acroporas. We were thinking 10-15 watts per gallon. That sound right? Frankly I need to read my books again for the numbers. :)

By the way metal halides are a possibility now. We are still seeking advice and haven't pinned down anything yet. We have an oak canopy, so are also concerned with any heat and fire hazard issues.

Thanks :)

[ATJ]

Please let me know the dimensions of the tank. This has more of a bearing on how effective the lighting is than the volume.

I do not use watts per gallon nor see any value in it. What is more important is the amount of light reaching the corals and as tanks come in all shapes and sizes, the volume of the tank does not really give a good idea how much light the corals are receiving.

I also don't subscribe to the idea that Acropora need massive amounts of light. There are over a hundred species and while some are common in shallow water, there are found over a great range of depths in nature. I have dived to over 40m (around 130') and not only are their Acropora colonies at that depth, I could see colonies in even deeper water. Of course, some species do better with more light and you will generally get faster growth with more light (with all other factors being ideal).

With the amount of light you already have you may already have enough for many Acropora species, depending on the dimensions of the tank.

[lossman]

Duh, my bad. LOL
72"Wide 28"High 18"Front to Back

<a href=showthread.php?s=&postid=9511167#post9511167 target=_blank>Originally posted</a> by ATJ
Please let me know the dimensions of the tank. This has more of a bearing on how effective the lighting is than the volume.

I do not use watts per gallon nor see any value in it. What is more important is the amount of light reaching the corals and as tanks come in all shapes and sizes, the volume of the tank does not really give a good idea how much light the corals are receiving.

I also don't subscribe to the idea that Acropora need massive amounts of light. There are over a hundred species and while some are common in shallow water, there are found over a great range of depths in nature. I have dived to over 40m (around 130') and not only are their Acropora colonies at that depth, I could see colonies in even deeper water. Of course, some species do better with more light and you will generally get faster growth with more light (with all other factors being ideal).

With the amount of light you already have you may already have enough for many Acropora species, depending on the dimensions of the tank.

[ATJ]

Ah, a high narrow tank - the perfect tank to show that watts per gallon is meaningless. :strooper:

These tanks are difficult to light (I know as I have two of them) and you get a lot of variation in light from the top to the bottom. This can be used to your advantage, though, as you can put the corals that prefer more light near the top and those that need less near the bottom. It is just a matter of aquascaping.

The narrow width will limit the number of fluorescent tubes (NO, PC, VHO or T5) and so you will be able to provide more light with metal halide.

If you were to go T5, you could just fit 8 rows of tubes with reflectors (624W if you went with 2 x 39W for each row). That will be less light than you have now, although with good reflectors you get around 50% more light reaching the tank. It may give you the equivalent of around 900W of what you have now.

In my opinion you probably have enough light already to keep most species of Acropora in your tank. Some you may need to keep in the upper half of the tank.

How much circulation do you have in the tank? What are your water parameters? If both of these are good, maybe you should try a frag of Acropora and see how it goes.