29" deep SPS tank 250vs400W

[Ixthys]

<a href=showthread.php?s=&postid=7104965#post7104965 target=_blank>Originally posted</a> by Travis
I can already guarantee that the majority of people are going to tell you that you need 400 watters (but have any of those people tried 250 watters on a tank deeper than 24" or are they just repeating what they have read?). That is really one of the most common "myths" in this hobby. I used to assume the same thing until I decided to go against the grain and try for myself. Somewhere along the line, somebody posted that you need 400 watters in any tank over 24". And the community seemed to accept that as fact for some unknown reason. I can tell you that it truely is a myth.

Travis- Very nice tank. While I think you are right that many folks just accept the 24" notion, at least some folks gaged depth as a limiting factor based on light meter readings. Any idea what kind of PAR you are getting at the bottom of the tank?

Also, I'd like to know what and how often you feed your corals.

Thanks...and again, very nice tank.

 

[Travis]

I don't have a PAR meter. It is on my Christmas list but santa keeps forgetting to bring it to me. No idea what the PAR is down there but it is plenty for the corals. In fact, I've had a couple occasions where a coral was moved from an area of inderect light to the bottom of the tank in direct light and bleached.

All I feed the tank is fish food. The corals probably get some of the juices and fine pieces from that along with the byproducts of the fish waste. Occasionally I will experiment with throwing in some GP's but the only result I usually see from that is increased PO4 but no effect on coral health or growth.

 

[Mogrash]

As stated before, really 400Watt SE are only necessary if you are going to run the 20k bulbs.

If you run 10k or 14k I would stick with the 250's. Reason is, the 250DE 20k bulbs have about half the PAR of 10k or 14k (the 15k XM are kinda inbetween the 10k and 20k). A 250DE 10k bulb produces close to the 400 Watt 10k bulb...in other words around 100+ PAR. Check out Sanjay's data. I am in the process of ditching my 250DE 20ks that I was running in my 210 because the growth is just not there. I will be replacing with either 14k or 10k to get the par doubled.

Actinic light will do little in a deep tank except for corals placed high in the aquarium (beyond the looks) compared to the MH.

400Watters are nice if you are going to buy the lumenarc or lumenmax reflectors. However, I am toying with the idea to add 3 more 250DE to my tank and really stagger the turning on of the lights and then the turning off of the lights. This would give a much better spread going from dawn to dusk then just 3 lights over a 210.