Hmmm.. Thinking 400w MH for my 80 is too much.. Thoughts?

[wintrmte]

After reading through some of the posts, I'm starting to think that the 2 400w MH's I ordered will be a bit much for my 80 gal tank..
I'd really like to keep clams and some hard / sps corals..
From the bottom to the top of my tank is 21", side to side is 48".
The canopy is 6 1/2" high, but from the top of it to water level is about 8 1/2"
Do you guys think the 400W will be too much for the fish and corals that are currently in the tank?

 

[dskidmore]

Bah! You can never have too much light! Start off slowly with a short photoperiod, maybe with only one MH, and then slowly increase the photoperiod.
Your enemy is algae, it will bloom if there are any nutrients to suck up. Might triple-check your water parameters before you start the lights, and if you don't have a refugium yet, it's a perfect use for your old lights that will keep the nutrients in check.
Any low-light corals/sponges you have will be particularly sensitive to the algae. If you see algae growning on them, consider re-arranging your rock to shelter and shade low-light inverts.
Heat may become an issue, you may need extra fans, and at worse a chiller.

 

[pwnag3!!]

dude for an 80 i would go with either 2x150 or one 250 MH

 

[starfishjackedme]

I started with my 400 watt Iwasakis over my 200, which is not a reef anymore. I put them over my 75, but 15" over the water. Since the 200 is only 4" taller, the offset hight makes it the same. I made my canopy with adjustable rails for the lights so I can raise or lower them. 10" is the closest I ever went to the water in the 200 though.

 

[wintrmte]

Interesting. Thank you for the replies. I'll have to see if I can get the canopy a bit higher off the water then.
It sounds like 8" might not be high enough.

 

[oyam1]

IMO twin 250w MH is the way to go.
i know a few people that feel 400w was an overkill for them.
also overkill on the elecric bill!:scared:

 

[golfish]

Originally posted by Wintrmte
The canopy is 6 1/2" high, but from the top of it to water level is about 8 1/2"

This will put the bulbs about 4-5" from the water after mounted, that might be a problem..I'd either make the canopy taller, cut the top off and use pendants or remove it all together and use pendants..

 

[dskidmore]

Originally posted by oyam1
also overkill on the elecric bill!:scared:
True. My father, the energy engineer, would never approve. (Although he does like Metal Halides for thier lumens/watt ratio.)

 

[gold strip]

Way too much light unless you are going to have an sps only tank. You will cook softies and lps. In my opinion you should stay with 250w max unless your tank is 28" deep or deeper.
But everyone has an opinion.

 

[wintrmte]

Hmm. Well, I got the 400W's in, and it does seem incredibly bright.
I've got plenty of airflow in there now so the tank temp isn't rising, but based on the last post, I'm concerned that I have just limited myself to one kind of coral by staying with the 400's... :S

 

[wintrmte]

Ok, we're gonna exchange the 400W's for two 250W MH's.. I think this will be a much better fit for our tank.
Thanks all for your suggestions!

 

[dskidmore]

Originally posted by Gold Strip
Way too much light unless you are going to have an sps only tank. You will cook softies and lps. In my opinion you should stay with 250w max unless your tank is 28" deep or deeper.
But everyone has an opinion.
I've heard differing opinions on that. Wild softies don't grow in the ocean with the less bright sun. Unless the coral is a deep water or cave coral, I don't see why it can't adjust to the brighter light. Acclimation is the key. Once again, no personal experience, I just read about the experience of others.

 

[wintrmte]

That's what I usually do as well. I think the two 250W's will be more appealing to the eye, rather than the two 400W nuclear blast effect that we had in there..

 

[msd2]

Originally posted by DSkidmore
I've heard differing opinions on that. Wild softies don't grow in the ocean with the less bright sun. Unless the coral is a deep water or cave coral, I don't see why it can't adjust to the brighter light. Acclimation is the key. Once again, no personal experience, I just read about the experience of others.
softies simply put wont tolerate very bright light in my experience, they do okay in caves/overhangs etc but if you were to put shrooms in direct light of dual 400 in a 80 gal tank ur just gonna either watch them wither away or try and migrate to a shadier spot. I run 2x250 & 175mh bulbs on a 100g and I even have to put the shrooms either at the bottom or under an cliff. My guess is this is where u would find them in the ocean as well, but im not sure, havent seen them in the wild yet:joy:
btw IMHO i think u made a good decision on going w/the 250's instead

 

[jmesmcm]

I run dual 400watts on my 90 but I am keeping primarily SPS. They do seem to cook lower light corals which need to be placed carefully into caves or such.

 

[wintrmte]

Well, I got the two 250W's in today and I have to say, the tank does look much, much better.
So, now with the two 250W's and 4 35W T5 Blues, will I be able to host some clams and softies?

 

[msd2]

Originally posted by Wintrmte
Well, I got the two 250W's in today and I have to say, the tank does look much, much better.
So, now with the two 250W's and 4 35W T5 Blues, will I be able to host some clams and softies?
yup, ur set for it pretty well. I have a sq. clam, and a few croc's and they are doing well