Question on metal halide and numbers.

bobme · 08/04/2017, 01:06 AM

I am still trying to do the math on running metal halide or leds. I know the cost to run leds would be less, but my house runs negative most the time for a ton of solar panels. I am most likely going to be getting a 8' x 4' x 18" tank or 24" tall tank. If I did run MH would I need 4 hoods or 8 do you guys think? I plan on housing mostly SPS. 18" 150 watts and 24" 250 watts?
Thanks for all your help guys.
- bobme

Ron Reefman · 08/04/2017, 04:18 AM

IMHO, if your tank is going to be 4' from front to back, you are going to need 2 rows of lights whether it's MH or leds. And if you are really going for mostly sps you might as well just go for the 250w MH over the 150w, but I think either will work.

The cost of electricity that the MH use vs the leds is only part of the cost. You are probably looking at a 1hp chiller ($1000+), quite a bit more use of the house A/C and then there are MH bulbs (8 every 2 years will be $400 to $600+). But then if you are doing a 500g sps tank, I have to assume cost isn't really a big concern?

bobme · 08/04/2017, 04:55 AM

Cost is a concern when it comes to lighting because - I want to make sure I do whats best for the tank and my home at the same time. When I do the raw math on MH vs LED it seems to be around 50% or so savings. However adding the extra power usage from a chiller and the bulbs lights themselves maybe I should just **** and go LED. I have a lot of costs with this tank, first of all is a remodel for the tank, running more power, backup generator for winter power outage, and lastly a fish room with its own AC.
If anyone else has something else to add about lighting feel free to chime in.
If not thank you for your help.

LobsterOfJustice · 08/04/2017, 05:23 AM

People always talk about the extra cost of a chiller, but for a lot of people, the extra heat is welcome for about half the year. People think chillers use a lot of electricity because they're measured in HP but most tanks actually will use more wattage in heating then cooling. So if you need to increase your heater wattage and use to make up for the lost MH heat in the winter, it's kind of a wash.

Sent from my iPhone using Tapatalk

alton · 08/04/2017, 05:43 AM

Depending on your layout if you keep everything in the center, 4 x 250w MH pendants would be fine. When I ran MH's (3 on a 300DD) during the summer I ran them only for 3 to 4 hours and my corals did great. Now I run leds and my savings are nill becasue I run Leds 10 hours versus the 3 to 4 hours in the summer. Also I run a heater in the winter which I never did before and I live in South Texas. Most large pendants give you the option of 250w or 400 just like electronic ballast. For me I like my Leds because of the clean look versus large pendants and not having to buy lamps. The first is my old 300 with MH, the second is my 180 with BML leds that replaced the 300. I kept my house at 76, the tank ran at 77 and never required a chiller

karimwassef · 08/04/2017, 06:05 AM

If it were me, I'd run 3 x 400W MH (1 x 3 matrix) if you're at 18". I would go with double ended HQI pendants and get as much UV with those as possible. Assuming you want coloration and growth

. I would use decent pendants to get decent coverage - I like the cayman sun - and raise them by about 18" until you get light at the tank bottom edges in a darkened room.

It's what I run today and needs a 1/2" hp chiller to keep the temp at 84F in summer in TX. But my sps like it hot. Of course, I do run an 18 hr photocycle and shut down above 84 so ~ 15hrs in the summer.

45commando · 08/04/2017, 08:18 AM

I also think that 4 x 250wt MH will be plenty for your tank. The style of reflectors & height of bulbs above the water can make a big difference.

There used to be a lot of debate years ago about MH bulb orientation in relation to tank length. It was supposedly better (from everything I read back then) to have the MH bulbs mounted perpendicular to the length of the tank, for maximum coverage. I have always mounted my bulbs that way & still do.

My 92 corner tank is 4' long at the widest & almost 3' front to back at the widest & a single 250wt SE bulb covers the entire tank. It is mounted 8" above the water & has a single 4" Icecap variable speed fan for cooling. HTH

bobme · 08/04/2017, 09:45 AM

I have been so concerned over "heat" that I never stopped to think about heating.

I think I still have a 3/4 hp chiller that's new in my shop from a old project that I really never even started. I hate selling things, so I just shoved it on a shelf and there it rests. I do keep my house around 74 degrees and maybe cooler in the winter. I tend to make more money with solar in the winter than summer so I try to take advantage of it. I am sure all that will change with the tank installed and running. I forget how many watts of heaters I ran with my old 300 gallon but it was a lot. So many the LED vs MH heat thing really wont be an issue.

grigsy · 08/06/2017, 06:15 PM

4 metal halides will be enough for that size tank with the right reflectors.

I don't run a chiller myself and most people I know that use MH don't run a chiller. When I used LEDs, my heater was on a lot and negated any energy savings that I expected when running LEDs. I didn't see savings.

biecacka · 08/07/2017, 09:44 AM

Depends on rock work. I run 1 400wt radium on my 48/48/24 cube. Almost all rock is in center.

Corey

jda · 08/07/2017, 03:41 PM

Larger tanks are made for reflectors.

I don't use chillers, even though I have them on hand, and I welcome every bit of heat from the IR - if you live in Arizona or Flordia, this might be different. Fans can do the job for the vast majority of people.

That is a large tank - large tanks are hard to light. I would recommend that you get a lot of advice from people who actually light large tanks instead of folks who mean well when thinking that their 180G (which is still small compared to yours) will scale, but really do not have a ton of useful experience. Of course, everybody know that a bio cube is the same.

Dr Joshi has a large tank. Google search his LED review - but basically, 3 Radions to replace every MH, no saving in electrical costs, more heater in the colder months and less chiller in the hot months (net zero). IME, his findings are pretty typical.

I would definately use 250w and spread them more if you do the 18" deep tank.

08/04/2017, 01:06 AM	#1
bobme Registered Member Join Date: Jun 2015 Posts: 9	Question on metal halide and numbers. I am still trying to do the math on running metal halide or leds. I know the cost to run leds would be less, but my house runs negative most the time for a ton of solar panels. I am most likely going to be getting a 8' x 4' x 18" tank or 24" tall tank. If I did run MH would I need 4 hoods or 8 do you guys think? I plan on housing mostly SPS. 18" 150 watts and 24" 250 watts? Thanks for all your help guys. - bobme

08/04/2017, 04:18 AM	#2
Ron Reefman Registered Member Join Date: Jul 2009 Location: Cape Coral, FL Posts: 10,431	IMHO, if your tank is going to be 4' from front to back, you are going to need 2 rows of lights whether it's MH or leds. And if you are really going for mostly sps you might as well just go for the 250w MH over the 150w, but I think either will work. The cost of electricity that the MH use vs the leds is only part of the cost. You are probably looking at a 1hp chiller ($1000+), quite a bit more use of the house A/C and then there are MH bulbs (8 every 2 years will be $400 to $600+). But then if you are doing a 500g sps tank, I have to assume cost isn't really a big concern? __________________ The good thing about science is that it's true whether or not you believe in it. (Neil deGrasse Tyson) Visit my build thread http://www.reefcentral.com/forums/showthread.php?t=2593017

08/04/2017, 05:23 AM	#4
LobsterOfJustice Recovering Detritophobe Join Date: Jan 2004 Location: Cary, NC Posts: 7,443	People always talk about the extra cost of a chiller, but for a lot of people, the extra heat is welcome for about half the year. People think chillers use a lot of electricity because they're measured in HP but most tanks actually will use more wattage in heating then cooling. So if you need to increase your heater wattage and use to make up for the lost MH heat in the winter, it's kind of a wash. Sent from my iPhone using Tapatalk __________________ If it's worth doing, it's worth doing right. I remember when zoanthids were called things like "green" and "orange" and not "reverse gorilla nipple." Current Tank Info: 180g reef with all the bells and whistles

08/04/2017, 06:05 AM	#6
karimwassef Registered Member Join Date: May 2004 Location: Dallas, TX Posts: 11,033	If it were me, I'd run 3 x 400W MH (1 x 3 matrix) if you're at 18". I would go with double ended HQI pendants and get as much UV with those as possible. Assuming you want coloration and growth . I would use decent pendants to get decent coverage - I like the cayman sun - and raise them by about 18" until you get light at the tank bottom edges in a darkened room. It's what I run today and needs a 1/2" hp chiller to keep the temp at 84F in summer in TX. But my sps like it hot. Of course, I do run an 18 hr photocycle and shut down above 84 so ~ 15hrs in the summer. __________________ Failure isn't an option It's a requirement. 660g 380inwall+280smp/surge S/L/Soft/Maxima/RBTA/Clown/Chromis/Anthias/Tang/Mandarin/Jawfish/Goby/Wrasse/D'back. DIY 12' Skimmer ActuatedSurge ConcreteScape

08/04/2017, 08:18 AM	#7
45commando Registered Member Join Date: Aug 2004 Location: Florida Posts: 1,321	I also think that 4 x 250wt MH will be plenty for your tank. The style of reflectors & height of bulbs above the water can make a big difference. There used to be a lot of debate years ago about MH bulb orientation in relation to tank length. It was supposedly better (from everything I read back then) to have the MH bulbs mounted perpendicular to the length of the tank, for maximum coverage. I have always mounted my bulbs that way & still do. My 92 corner tank is 4' long at the widest & almost 3' front to back at the widest & a single 250wt SE bulb covers the entire tank. It is mounted 8" above the water & has a single 4" Icecap variable speed fan for cooling. HTH __________________ "It's not the size of the dog in the fight;It's the size of the fight in the dog!" -Sir Winston Churchill. Current Tank Info: 92G Corner tank, 250 wt 14K MH, 20G sump, 5G fuge, mixed reef

08/04/2017, 04:55 AM	#3
bobme Registered Member Join Date: Jun 2015 Posts: 9	Cost is a concern when it comes to lighting because - I want to make sure I do whats best for the tank and my home at the same time. When I do the raw math on MH vs LED it seems to be around 50% or so savings. However adding the extra power usage from a chiller and the bulbs lights themselves maybe I should just **** and go LED. I have a lot of costs with this tank, first of all is a remodel for the tank, running more power, backup generator for winter power outage, and lastly a fish room with its own AC. If anyone else has something else to add about lighting feel free to chime in. If not thank you for your help.

08/04/2017, 09:45 AM	#8
bobme Registered Member Join Date: Jun 2015 Posts: 9	I have been so concerned over "heat" that I never stopped to think about heating. I think I still have a 3/4 hp chiller that's new in my shop from a old project that I really never even started. I hate selling things, so I just shoved it on a shelf and there it rests. I do keep my house around 74 degrees and maybe cooler in the winter. I tend to make more money with solar in the winter than summer so I try to take advantage of it. I am sure all that will change with the tank installed and running. I forget how many watts of heaters I ran with my old 300 gallon but it was a lot. So many the LED vs MH heat thing really wont be an issue.

08/06/2017, 06:15 PM	#9
grigsy Registered Member Join Date: Sep 2003 Location: Santa Cruz, CA Posts: 2,307	4 metal halides will be enough for that size tank with the right reflectors. I don't run a chiller myself and most people I know that use MH don't run a chiller. When I used LEDs, my heater was on a lot and negated any energy savings that I expected when running LEDs. I didn't see savings.

08/07/2017, 09:44 AM	#10
biecacka Registered Member Join Date: May 2008 Location: Columbus Ohio Posts: 6,361	Depends on rock work. I run 1 400wt radium on my 48/48/24 cube. Almost all rock is in center. Corey

08/07/2017, 03:41 PM	#11
jda Dogmatic Dinosaur Join Date: Feb 2004 Location: Boulder, CO Posts: 6,256	Larger tanks are made for reflectors. I don't use chillers, even though I have them on hand, and I welcome every bit of heat from the IR - if you live in Arizona or Flordia, this might be different. Fans can do the job for the vast majority of people. That is a large tank - large tanks are hard to light. I would recommend that you get a lot of advice from people who actually light large tanks instead of folks who mean well when thinking that their 180G (which is still small compared to yours) will scale, but really do not have a ton of useful experience. Of course, everybody know that a bio cube is the same. Dr Joshi has a large tank. Google search his LED review - but basically, 3 Radions to replace every MH, no saving in electrical costs, more heater in the colder months and less chiller in the hot months (net zero). IME, his findings are pretty typical. I would definately use 250w and spread them more if you do the 18" deep tank.