I have (2) 400w metal Halide lights in my 120g tank and i think i have to much light. I have a chiller so water temp it not the issue. The coralline algae turned from purple to white under the lights and any coral i put in the spot under the lights turn white (i move them before they die). I cannot lift the lights any higher over the water because i have a canopy. I run a fan on the lights in the canopy and have a chiller.
Everything is fine in the tank except directly under the light is a dead zone. I would like to move to a smaller light but $$$$.
if it were me i would try to take the top off the canopy or just remove it, those are hot running lights for under canopy use IMO.
also any coral under those should be light acclimated from the bottom up move them up to where you want them over a month or two, if you just put the lights over the tank replacing existing light you could try what someone suggested to me just yesterday i think, layer 5 screens over the tank to shade it then remove one every day or everyother day to acclimate the tank to the light.
HTH
is your tank a 48"x24x30? or is it a 6 foot at 24 inch depth, if its 24" surface to bottom then you might have a bit much as 2x250w would light the depth enough.
if you already have the 400’s and don’t want to spend for lesser lighting, up the color temp.
buy some 20k lamps. the tank will look pretty cool and it will have less PAR.
-it’s not necessarily too much light, especially if your tank is sps dominant, but as stated, the corals must be acclimated gradually.
btw- coralline thrives in lower light conditions. you aren’t going to get any in the direct light of 400 watt halides IME.
I have a 400 and trust me, these can be too much light even for SPS depending on the depth of the tank.
Rich - you could always put some eggcrate on the top of the tank to diffuse the light. Not only will it keep it jumpers but it seems to amplify the shimmer effect and looks very cool.
Another more expensive option is to replace your ballasts with dimmable ballast. Thats what i have on mine and it lets me run my lights anywhere between 70-100% which is convienent in so many ways. They arent that expensive and you could always upgrade one at a time and sell your current ones to help compensate for the costs.
i know a guy that keeps sps under 17" of water under 400 watt halides. he claims his growth didn’t take off until he upgraded to them. he has a 1000 gallon shallow reef.
17" tank or 17" of water? Its a big difference between the two!
Im still trying to dial in my 400MH as i type this. I have the bulb in my pendent suspended exactly 32" above
the eggcrate in an 8" propagation tank and im still nuking corals at only 70% power. There is only about 4" of water between the frag rack and the top of the water. I just cant seem to find the sweet spot and ive decided to wait for the club to buy a PAR meter so i can get the tank charted and dialed in just right.
[quote=“logans_daddy, post:6, topic:2544”]
ive decided to wait for the club to buy a PAR meter so i can get the tank charted and dialed in just right.[/quote]
when does that look like its happening, i’d love a reading on my tank!
Seriously, i would like to get the meter VERY soon but im not sure how soon it will be before it is available to club members. We are still trying to work out the details that would allow club equipment to be available to the most people while being able to make sure that the equipment is protected against damage and theft. We also need a way to “insure” equipment so that we can replace it in the case of accidental damage. Im pretty sure that asking for a $300 security deposit is out of the question ;D We have a low range PO4 photometer that will also be available as soon as we get the details worked out. We will post all the details as soon as we have them!!
something like that wouldn’t need to be borrowed, how many times do you need to have PAR read a year? maybe once when you figure your lights are going. with a PAR meter an officer could on request bring it over to members house for either gas money or a beer :BEER
in fact it would be better to have a club officer bring the equipment over for one time readings, this way there is no “someone stole it” or even, “yea you can borrow it when xxxx is done with it” and he’s done with it in 2 months…
south DE could be an issue but im sure something could be worked out
dvrc has one. actually, i have it in my posession right now. they make you put up a 25 dollar deposit, and a 5 dollar rental fee. i don’t see how 25 bucks would stop someone from keeping it, but that’s what they do.
now, you might want to contact the officers because i heard they got theirs for 150 bucks or something super cheap like that.
i for one would like to have access to a PAR meter various times throughout the year to see what time does to my lamps.
[quote=“logans_daddy, post:6, topic:2544”]
17" tank or 17" of water? Its a big difference between the two![/quote]
i am pretty sure the water is 17" deep to the bottom of the tank.
I know T5s real well and honestly don’t know much about MH. that being said today I read something in Calfo’s coral book about how most hobbyst over use and don’t need 400W MHs. Will try to get quote tomorrow. Sitting in theater now waiting for Avatar to start.
something like that wouldn't need to be borrowed, how many times do you need to have PAR read a year?
I dont think that will be the case. Specifically because of:
i for one would like to have access to a PAR meter various times throughout the year to see what time does to my lamps.
exactly.
they make you put up a 25 dollar deposit, and a 5 dollar rental fee.
thats very similar to the options we are discussing now along. your right about the $25 not covering the meter thats why we need to be selective about who can rent and who cant. obviously letting someone that just joined the board yesterday rent a $300 meter for $5 might not be a good idea ;D
got theirs for 150 bucks or something super cheap like that.
im betting it was from the reeftalk.com groupbuy. they got an insane price on them and a lot of people took advantage of it, especially clubs.
i use 150's over 17" of water, so i don't agree with the 400s
I agree. i use 250s over all my othe tanks includign my sps tank. i went with the 400 dimmable because i bough the big lumenbright reflector and it allows me to cover my entire frag tank with only one bulb because i can hang the reflector so high. the laternative would have been 2 150MH or 6 X 48" T5.
[quote=“Gordonious, post:12, topic:2544”]
Sitting in theater now waiting for Avatar to start. [/quote]
awesome flick IMO.
i saw it yesterday.[/quote]
i hate those kinds of movies, but really did like avatar. a great leap forward in technology.
FOCUS- remember MH not Avatar. JK- I saw the movie this weekend as well and it was good.
My tank is 48x24 and the lights are only 4" above the water. The glass gets really hot so i dont think i can put anything under the lights but will try egg crate. The depth is 24" but the rock is about 14" from the top. When i do introduce a coral i put it on the sand and have to wait a month b4 i move it to a spot.
I spent all the money and bought the 20k radium bulb but it is still too hot. I cannot remove or modify the canopy because it is furniture quality and in the living room. My wife tolerates a lot of fish tank stuff but will not budge on the “look” of the tank.
I can only run it 5 hours a day because the heat. I tried to run it 8 hours over xmas for viewing pleasure and the corals said NO. I am back to 5 hours a day.
a 400 watt bulb is a 400 watt bulb. one is not going to put off less heat than the other. i was speaking of color temperature, not actual temperature. you need to put fans in the canopy to push the heat away.
running the lights for less time is not going to work. imagine staring at the sun. staring the sun for an hour or 8 hours…either way, your still blind.
you bought a high PAR 20k lamp. if you wanted to have less PAR, you should have purchased a weak one.
try a crappy ebay bulb. they have low PAR ratings for the most part.