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MH ? 250 or 400

reefsandrotts

reefsandrotts

NJRC Member
A friend of mine is looking to do a tank that is 28" deep and was wondering if he should go 250 or 400 watt halides he wants to keep LPS,SPS.
Any help would be great.
 
panmanmatt

panmanmatt

Officer Emeritus
Officer Emeritus
250 if he is using HQI (double ended) bulbs and 400 if going single ended. Personally I would go with the 250 HQI.
 
B

billyr98

i have had two 30" deep tank, and I used 400w Single ended on both.. electrically i would love to run 250s, but i already own the ballast and lamps :) You can get the same results with 250s, just depends on what lamps you are going to run..
 
Phyl

Phyl

Officer Emeritus
Officer Emeritus
I'm running 400SE on a 24" deep tank. I could grow SPS inside the stand under the tank, if I wanted to. LOL.
 
H

harryk

I have the same Dilemma. My tank is 30" tall, but i'm leaning towards 250's 400's would work too. It's all preference i think.

Harry
 
reefsandrotts

reefsandrotts

NJRC Member
reefsandrotts said:
A friend of mine is looking to do a tank that is 28" deep and was wondering if he should go 250 or 400 watt halides he wants to keep LPS,SPS.
Any help would be great.
Click to expand...
Ok just found out he did a canopy like mine that is 16" high so the light would be I guess at minimum 12" off the water for airflow.So is 250 still an option?
He also said HQI.
Thanks again
 
D

DaveK

400w MHs would give great light, but you are going to be consuming a lot of power and producing a lot of heat. On an extremely deep tank, there might not be any other good choice. However, on a 28" deep tank, I'd go with 250w MH. Remember you can always add another bulb or two over the tank.
 
Phyl

Phyl

Officer Emeritus
Officer Emeritus
DaveK said:
Remember you can always add another bulb or two over the tank.
Click to expand...

FWIW, this would not be equivilent to running 400s (and may well end up wasting more money than it is saving if you're adding extra bulbs). 1 400w bulb will penetrate deeper than 3 250s even if you placed them all in one spot.

With the right reflector, you might be able to use 1 400w bulb per 3' rather than 2'. I think BillyR is running 3 bulbs on a 8' tank.
 
D

DaveK

Phyl said:
DaveK said:
Remember you can always add another bulb or two over the tank.
Click to expand...

FWIW, this would not be equivilent to running 400s (and may well end up wasting more money than it is saving if you're adding extra bulbs). 1 400w bulb will penetrate deeper than 3 250s even if you placed them all in one spot.

...
Click to expand...

I fail to see how this could be true. Two 250 watt bulbs are going to produce somewhat more light that an single 400 watt bulb, all other things being equal. While you might get a brighter spot directly under a 400 bulb, the overall amount of light in the tank is going to be greater with two 250w bulbs. Again, all other things being equal.
 
C

Carlo

Yea, I'd have to agree with DaveK. All things being equal you're going to get more PAR spread out over a greater distance with multiple 250s then a single 400. You're also going to get more light directly under the lamps especially if they are right next to each other.

Keep something in mind. There isn't much light difference between a 250 and a 400. Remember it takes a 4 fold increase in wattage to get twice the amount of light. With that said it would take going from a 250 to a 1000 watt lamp (all else being equal) to get 2 times the output. Going from a 250 to a 400 could be a step down in light depending on the type of unit used. For example an electronic HQI 250 will typically out perform or equal a 400 watt single ended lamp.

Just for the record on my 30" 265g I'm running double ended HQIs on electronic ballasts and run 4 lamps spread out over the entire length of the tank. 2 are 10K 175 watt and 2 are 20K 250 watt. I've never had any problem growing anything on the bottom of the tank. The light is also much more evenly distributed then I'd get with 2 or 3 400 watts lamps.

I was just talking to Chris (IceCap) on Wednesday about a similar type setup and he recommended going with 2 HQI 250s over 2 400w Single Ended Moguls for a tank and mentioned the light output would be about the same as HQIs put out more penetrating light then Moguls do.

Just a personal opinion but I'd never go Mogul again unless I needed a lamp that didn't have an HQI equivalent or I needed to reuse equipment I already had on hand or could pick up cheap.

Carlo
 
mikem

mikem

Officer Emeritus
Officer Emeritus
The whole question here now is the PAR (penetration). You can have 5 250watt bulbs and 1 400watt bulb in the same tank and your not gonna get the PAR out of the 250watters.
I had 2 250 watts and 1 400watt lights on a 24inch high tank, same frags on the bottom , and the frags under the 400watter had more viberent colors. Same K bulbs.
For having 2 250 watts, yes it might be a little brighter then 1 400watter, but now your paying for an extra 100watts of electric.
Just my experience with experimenting with lighting and bulbs for many years.
 
M

mr_X

i'm switching from sunlight supply 400 watt ballasts to 250 watt ballasts. too strong for anything but sps IMO.
 
M

mr_X

oops- my tank is 25" deep. i can keep sps on the sand bed with no problem at all. LPS bleaches out. i actually have maze brains UNDER the rockwork getting indirect light, and they are doing alot better than out in the direct light. i couldn't decide on what bulbs...so i have 1 ushio 14k, 1 hamilton 14k, and 1 reeflux 12k. the PAR of the ushio is best, and the look of the reeflux is best IMO.
 
B

Brian

Officer Emeritus
Officer Emeritus
FWIW I have a 30" deep tank and I run 3 x 250 watt XM 10k's and they are about 10-12" off the water. I have no problem with SPS just about anywhere in the tank...unless they are on the bottom out of direct light.
 
H

hayabusa2003

Carlo said:
Keep something in mind. There isn't much light difference between a 250 and a 400. Remember it takes a 4 fold increase in wattage to get twice the amount of light.
Click to expand...

Is this from emperical data? If it is, I'd be interested it what the actual measured light different was between the 250 and 400. The 150watt difference has to go somewhere :) If there isn't much difference in PAR, then I would imagine the power converted to heat, implying the 400watt ballast is way inefficient.

Carlo said:
For example an electronic HQI 250 will typically out perform or equal a 400 watt single ended lamp.
Click to expand...

With our without shielding? I thought once you put the mandatory shielding on the HQI, the PAR output wasn't much different than a SE bulb. I'm no bulb manufacturer, but if I crack the glass around my 175watt SE, what's left looks just like an HQI bulb :)
 
M

mr_X

i don't think that there is a huge difference between hqi and SE, but that's another thread. again, i'd save the electric, and go with the 250's.
btw...look what Santa brought!..it's Christmas in feb. ;D
newballasts.jpg
 
C

Carlo

hayabusa2003 said:
Carlo said:
Keep something in mind. There isn't much light difference between a 250 and a 400. Remember it takes a 4 fold increase in wattage to get twice the amount of light.
Click to expand...

Is this from emperical data? If it is, I'd be interested it what the actual measured light different was between the 250 and 400. The 150watt difference has to go somewhere :) If there isn't much difference in PAR, then I would imagine the power converted to heat, implying the 400watt ballast is way inefficient.

Carlo said:
For example an electronic HQI 250 will typically out perform or equal a 400 watt single ended lamp.
Click to expand...

With our without shielding? I thought once you put the mandatory shielding on the HQI, the PAR output wasn't much different than a SE bulb. I'm no bulb manufacturer, but if I crack the glass around my 175watt SE, what's left looks just like an HQI bulb :)
Click to expand...
It goes back to Einstein and his calculations. Without getting technical, it actually applies to many different things in the light and electrical world. Light will be 4 times "dimmer" at twice the distance from the light source. It takes 4 times the light increase in "power" to double the intensity. It takes 4 times the transmitter power to "talk" twice as far (ie. CBs/Amature Radio/FM radio), etc...

Carlo
 
H

hayabusa2003

carlo, that I get :) The company I work for builds long-haul DWDM systems (fiber optic transport) I was just wondering if you had quantitive values for the light output between a 200 and 400 watt setup, everything else being equal. You mentioned that there was little difference between the two, and that suprises me. I understand it's not a linear increase, but I'm curious if you had values to quantify the term "little" :) That is relative ;)

Hope you don't take this as me challenging your statement in any way. Just gathering as much info as I can :)

thx!
 
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