125g tank mh question

gimmiecpt · 01/27/2009, 09:37 PM

Hey all,
I just upgraded to a 125g tank and am building it slowly. I just bought 2 mh 250w lights and reflectors off of RC. The seller said they were new 20k bulbs, however one is blue, and one is not. Is there any way to tell the k rating of the non blue bulb?

Second question,
I have a canopy on the tank, and have secured the the mh & reflectors to the top of it. After reading forums here, it is stated that mh lights should be 16" off of the water. Is it going to be a problem if mine are only 8" off of the water? If so, what can I do to keep them at that height? change the bulbs to 175w?

Third question,
There is a glass top to this fish tank. Will the glass hinder the light in any way?

Thank you guys for taking the time to help me with my new tank.

gimmiecpt · 01/27/2009, 09:38 PM

Sorry,
The demensions of the tank are 72"L x 18"W x 21"H

BLANKENSHIP76 · 01/27/2009, 09:47 PM

Take the glass off the tank its useless.

I keep my halides 8inches off the water, it all depends on whether you are having a heat issue. Removing the glass top will help avoid heating issues and the light will penetrate the water better without the glass. If you are having heat issues and can't raise the light then add a clip on fan to the tank put it on the same timer as the haildes, and that will usually help with the heat.

As far as the bulbs go, they may be the different or they may just be cheap bulbs that don't look the same. It is important to buy good bulbs, they are crucial the appearance and health of the tank.

Also it may be tough to get good light coverage only having 2 lights 8 inches off the water, on a 6 foot tank you almost need 3 lights.

Anyway, good luck, hope that answered your questions.

grigsy · 01/27/2009, 09:49 PM

There is a burn in period for metal halide bulbs generally of 100 hours. During that time, the Kelvin may be a bit off. If the 20K bulb you bought doesnt blue up in 100 hours of use, you should contact the person you purchased it from and ask for a replacement. It would also be a good idea to switch the bulbs around into their different sockets - just to make sure there isnt an issue with the ballast instead.

It will be ok for you to keep your halides 8 inches above the water since you have a glass top on the tank. Water splash wont be a problem obviously and at 8 inches above you likely wont have a major issue with heat transfer.

devgru · 01/27/2009, 11:40 PM

i originally had my glass on my 125g because i was affraid of splashing,but took them out some time ago,only thing i noticed was slightly faster evaporation.i had 3x175w(no sps/lps at time) mounted 6"from water and had 6 12vDC PC fans(3 in/3out to help with heat

tbar · 01/28/2009, 04:09 PM

My bulbs are about 8.5" off the water with no glass for almost two years with no problem. I am also pleased with the coverage I have with only two bulbs.

gimmiecpt · 01/28/2009, 05:04 PM

Thank you all for your responses. The reason I asked about the glass was because I was worried about heating the water in the tank, and the splashing. Is there a big difference on the temp of the water if the glass is on vs. off?

On the topic of 2 vs 3 light. Originally I wanted 3 lights for full intense coverage, however after looking through forums I have found that it may be better to just have 2. That allows some softies and other plants to enjoy the tank, without have to adapt them to intense light. Am I correct on what I read?

Thanks again all,

Adam

customcolor · 01/28/2009, 06:36 PM

another point about the glass would be that if you put it on you will loose some good water to air mixing for O.

gimmiecpt · 01/28/2009, 10:06 PM

I hadn't thought of the oxygen ratio ... hmmm will have to take them off again.

01/27/2009, 09:37 PM	#1
gimmiecpt Registered Member Join Date: Dec 2008 Posts: 4	125g tank mh question Hey all, I just upgraded to a 125g tank and am building it slowly. I just bought 2 mh 250w lights and reflectors off of RC. The seller said they were new 20k bulbs, however one is blue, and one is not. Is there any way to tell the k rating of the non blue bulb? Second question, I have a canopy on the tank, and have secured the the mh & reflectors to the top of it. After reading forums here, it is stated that mh lights should be 16" off of the water. Is it going to be a problem if mine are only 8" off of the water? If so, what can I do to keep them at that height? change the bulbs to 175w? Third question, There is a glass top to this fish tank. Will the glass hinder the light in any way? Thank you guys for taking the time to help me with my new tank.

01/27/2009, 11:40 PM	#5
devgru Premium Member Join Date: Nov 2006 Location: casselberry,fl Posts: 523	i originally had my glass on my 125g because i was affraid of splashing,but took them out some time ago,only thing i noticed was slightly faster evaporation.i had 3x175w(no sps/lps at time) mounted 6"from water and had 6 12vDC PC fans(3 in/3out to help with heat __________________ It's time's like these when I think of the immortal worlds of socrate's who said "I drank what?" Current Tank Info: 125g w/125g sump/fuge,ACIII,RIO26hf,MAG9.5,PS,sulfer denitrate

01/28/2009, 04:09 PM	#6
tbar Registered Member Join Date: Aug 2005 Location: SE Virginia Posts: 452	My bulbs are about 8.5" off the water with no glass for almost two years with no problem. I am also pleased with the coverage I have with only two bulbs. __________________ I have done a 5 gal water change (about 17%) every week since week one. Hopefully having this posted here will motivate me enough to keep doing so. Current Tank Info: 33L, Two 36" 24 watt Marineland LED's, Tunze 9002 Skimmer, 2 Koralia 1's, pico hob filter for carbon.

01/28/2009, 06:36 PM	#8
customcolor Registered Member Join Date: Dec 2006 Location: kaukauna, wi. Posts: 3,879	another point about the glass would be that if you put it on you will loose some good water to air mixing for O. __________________ PLEASE DONT USE GREAT STUFF (THE YELLOW STUFF) IN YOUR TANK........USE POND FOAM (THE BLACK STUFF).. I BEG YOU! Great stuff====$5 a can 24-48 hour cure Epoxy to cover it====little as $5 for small projects or up to $100+ for larger projects and another 24-48 hour cure I hope you covered it well cuz if you didnt it will start to break down in a few months sand is another added cost to cover up the yellow. Pond foams====$9-$15 a can 24-48 hour cure DONE! You can cover it with sand if you want to (YOU DONT HAVE TO) though but thats added cost again Current Tank Info: 75 gal under way

01/27/2009, 09:38 PM	#2
gimmiecpt Registered Member Join Date: Dec 2008 Posts: 4	Sorry, The demensions of the tank are 72"L x 18"W x 21"H

01/27/2009, 09:47 PM	#3
BLANKENSHIP76 Moved On Join Date: Jun 2004 Location: Indianapolis Posts: 827	Take the glass off the tank its useless. I keep my halides 8inches off the water, it all depends on whether you are having a heat issue. Removing the glass top will help avoid heating issues and the light will penetrate the water better without the glass. If you are having heat issues and can't raise the light then add a clip on fan to the tank put it on the same timer as the haildes, and that will usually help with the heat. As far as the bulbs go, they may be the different or they may just be cheap bulbs that don't look the same. It is important to buy good bulbs, they are crucial the appearance and health of the tank. Also it may be tough to get good light coverage only having 2 lights 8 inches off the water, on a 6 foot tank you almost need 3 lights. Anyway, good luck, hope that answered your questions.

01/27/2009, 09:49 PM	#4
grigsy Registered Member Join Date: Sep 2003 Location: Santa Cruz, CA Posts: 2,307	There is a burn in period for metal halide bulbs generally of 100 hours. During that time, the Kelvin may be a bit off. If the 20K bulb you bought doesnt blue up in 100 hours of use, you should contact the person you purchased it from and ask for a replacement. It would also be a good idea to switch the bulbs around into their different sockets - just to make sure there isnt an issue with the ballast instead. It will be ok for you to keep your halides 8 inches above the water since you have a glass top on the tank. Water splash wont be a problem obviously and at 8 inches above you likely wont have a major issue with heat transfer.

01/28/2009, 05:04 PM	#7
gimmiecpt Registered Member Join Date: Dec 2008 Posts: 4	Thank you all for your responses. The reason I asked about the glass was because I was worried about heating the water in the tank, and the splashing. Is there a big difference on the temp of the water if the glass is on vs. off? On the topic of 2 vs 3 light. Originally I wanted 3 lights for full intense coverage, however after looking through forums I have found that it may be better to just have 2. That allows some softies and other plants to enjoy the tank, without have to adapt them to intense light. Am I correct on what I read? Thanks again all, Adam

01/28/2009, 10:06 PM	#9
gimmiecpt Registered Member Join Date: Dec 2008 Posts: 4	I hadn't thought of the oxygen ratio ... hmmm will have to take them off again.