MH Tank upgrade question

[MT79]

I'm planning for an "upgrade" to a 55 gal. I'm going with MH lighting, supplemented by 2x 48" VHOs. Regarding heat-how much more would a 250 mh put out compared to a 175? I'm basically trying to avoid adding a chiller. Should I go 2x175 or 2x250 mh? Will it make much difference? FWIW, I'm going to install a fan (or two?) in the canopy. Any advice, personal experiences much appreciated.

 

[Sam]

Well I think the first question that needs to be asked is:

What are you planning to keep in the tank?

Based on your stocking list, this will determine how much lighting you need. Basically for a typical reef system, rule of thumb is around 3-4 watts/gallon. Based on even using 2-VHO and 2-175W MH, you are talking about 10 Watts / gallon. That is a serious tan my friend

 

[MT79]

I want to keep everything LOL!! I'm not worried about too much light, just heat.

 

[Sam]

Well for the heat you will probably need a two fan set up in the canopy, one pushing and one pulling. Those MH drive a wicked amount of heat. my set up is with 2-VHO and 2-175W MH and I have a 135G.

Seriously, if you dump that much light in the tank, you will probably compromise some of your corals and anemone due to 'light shock.' research the lighting needs of your inhabitants before you decide.

 

[MT79]

Well I paln on adding a few SPS. I know it's going to take awhile to light acclimate everything I already have. I know of people who have 175-250 mh's on 20-30 gal. tanks so I don't think 2x250 is ridiculous for a 55 gal, they are 48" long(and I'll never have to upgrade if I go bigger). Plus I can get a good deal on 250's, the 175's may end up costing me more(not sure). Thanks Sam.

 

[Sam]

Good luck with it. 8)

 

[klam]

You are also going to want a fan blowing across the top of your water to help cool the tank down. This will also increase your evaporation rate so you will have to top-off the tank more.

Acclimate you corals to light by either 1)mounting the MH up high and slowly lowering them to you desired level over a few weeks or so. 2) place multiple layers of screens(screens on a screen door) to cover the tank top, remove one screen every couple of days or so.

 

[MT79]

Acclimate you corals to light by either 1)mounting the MH up high and slowly lowering them to you desired level over a few weeks or so. 2) place multiple layers of screens(screens on a screen door) to cover the tank top, remove one screen every couple of days or so.

Thanks Klam, that was my next question!...wow there are alot of things to plan out!! I'm still working on the stand/canopy(DIY) and equipment and trying to work around adding a chiller lol.
PS- A 150watt MH on a 14 gal...I bet that's a colorful tank!

 

[ellisz]

I think a 2x250 would be ok but heat will definately be an issue. I have a 2x250 on my 75 and I have 2 3" fans blowing out and the back of the canopy is made of peg board. My temps are hitting 75F and 73 if I have a fan blowing full blast on my sump. Evaporation is wicked with the fan though.

I am planning on putting bigger fans in. Hopefully that will work

Good luck

 

[MT79]

How much of an increase in temp. would you say you had after adding the MH's?(Or did you start w/ that setup?) FWIW I run mt tank at 81F. I would like to add a sump in the future but it's not in the budget now. So the only surface area I'll have is in the 55gal display.

 

[ellisz]

I used to keep my temp between 81-82. I get a good 3 degree bump. I think bigger fans would help. A well ventelated canopy should be fine but I can't speak from experience yet. I hate have in the fan on the sump but it does not hurt. Would not work for you though.

 

[MT79]

Thanks ellisz, and good luck w/ the bigger fans.