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Mr.First

Junior Member
Location
Nassau
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Looking to purchase a MH/VHO 36" light. Can I get away with a 400 Watt M/H directly on top of the tank, without a chiller ?

It is a 70 Gallon Oceanic tech tank 36 x 18 x24
 

masterswimmer

Old School Reefer
Vendor
Location
NY
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A 400w light will give you great penetration for depth. It won't give you any more spread though. Most pendants will get approximately 2' of spread on the light. The intensity of the light diminishes as it reaches the farthest points on the spread.

In your case, on a 36" tank, the farthest 6" on each end of the tank bottom will be relatively dark. Ideally you should use two bulbs. 250w should work fine.

Russ
 

herman

Moderator
Location
Weehawken, NJ
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All lights will heat up the tank substantially. For a tank like yours 2 x 250w is sufficient for keeping SPS and clams.

You have several options:

1. Build a canopy (not as hard as most think) Stick 2 x lumenarc minis in there with 250watters. For ballast you can use the Icecap MH250 - an awesome ballast worth every penny. If you use 14k or higher light you will not need to supplement with actinics. Because the lumenarcs are big you cant fit anything else anyway. Use fans to exhause and ventilate the hood.

2. Build a canopy and put two reflectors in there like the reefoptix III. Its a great pendant but smaller than the lumenarcs. In front and behind the fixture add T5s with an SLS reflector on the Icecap 430 ballast. With this setup you can use 10k for the MH and use actinics to supplement. Also you can extend the photoperiod using the actinics without the hefty bill the MH creates.

3. Go all T5 with various bulbs and multiple ballasts.


As far as heat goes, youd be surprised how effective fans can be if pointed towards the water.

4. Get a ready made fixture
 

meschaefer

One to Ignore
Location
Astoria
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Amzingly enough, that is the same dimensions of my 65 gallon AGA tank. I agree that you need two bulbs in order to get a good spread. I am using 2 175watt MHs with parabolic reflectors, and 2 x 65 watt PC actinics.

Remember that if a MH bulb is generally thought to give a good spread of 2 foot, with two blubs over a 36 inch tank that there is going to be alot of overlap in the middle. When I moved my stock into the 65 from a 4 foot 75, I though about upgrading to 250 watt bulbs as I was going strictly SPS, but decided that it was not necessary due to the overlap. I have had good results so far with alot of growth, even down low. I have had somoe color issues on some peices, but after trouble shooting the issue those on this board with people that I trust, we came to the conclusion that it was a phosphate problem as opposed to lighting.

ALthough I have no first hand experience with them, I have been told/led to beleive that Luminerc Reflectors can give you good spread over three foot. Although they are pricey, if they save you the cost of a second ballast and on replacing a second bulb every year, you will quickly recoup the cost. It is worth investigating into, perhaps those with experience or more knowledge on them will chime in.
 

meschaefer

One to Ignore
Location
Astoria
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Oh yea - If was purchasing new lights I probably would have gone with 250watts, if for no other reason that I was told they are a necessity for SPS.

Now that I have used the 175s, I don't think I will upgrade them on this tank, but I am considering changing to luminerc reflectors sometime in the future (They are on the two do list, but fall somewhere beind a battery back up and a chiller)
 

Mr.First

Junior Member
Location
Nassau
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29   0   0
Thank you so much for the excellent input. I think I will go the same as Mesc. (2)175 MH but with T5's Any thoughts on the T5s. Also, what unit do you have and where did you get it ? I am in Astoria as well, I understand the desire for battery backup.
 

meschaefer

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Location
Astoria
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What are you planning on keeping?

I use a dual Blueline electronic ballast, although I would look into either Ice Cap or ARO. You also want to make sure that you are using a good bulb. You can compare ballasts and bulbs here.

The only reason that I used PCs is that either nobody was using T5 or that they where just unavailable when I bought the ballast (I don't remeber exactly but I have had the ballast for about 4-5 years if not more). If I was going to buy them today, I would use T5s for my actinic supplementation.
 

Henrye

Junior Member
Location
NYC
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Battery backup for lighting, especially ~400W with T5's would be financially unattractive. It's also unnecessary. What kills your tank during a power loss is the loss of circulation. No circulation, no oxygen exchange, no life. Powering a heater is also reasonable during an outage to maintain water temperatures. The size and type of backup power supply will depend on the plumbing of your system and circulation plan (power heads or closed loop? If using a sump, what's size return pump). Keep in mind that computer backup batteries are designed for short term use to allow for a graceful shut down, not to keep running all day. They're also not built with an inductive load in mind, as pumps demand.

For a 70g tank that is at risk for a short to moderate power loss, get a marine battery with a current inverter. If power loss is common or will last more than several hours, you should really consider a generator.

Henry
 

meschaefer

One to Ignore
Location
Astoria
Rating - 100%
30   0   0
Battery backup for lighting, especially ~400W with T5's would be financially unattractive. It's also unnecessary. What kills your tank during a power loss is the loss of circulation. No circulation, no oxygen exchange, no life. Powering a heater is also reasonable during an outage to maintain water temperatures. The size and type of backup power supply will depend on the plumbing of your system and circulation plan (power heads or closed loop? If using a sump, what's size return pump). Keep in mind that computer backup batteries are designed for short term use to allow for a graceful shut down, not to keep running all day. They're also not built with an inductive load in mind, as pumps demand.

For a 70g tank that is at risk for a short to moderate power loss, get a marine battery with a current inverter. If power loss is common or will last more than several hours, you should really consider a generator.

Henry

Never said the battery back up was for the lights.:splitspin
 

Mr.First

Junior Member
Location
Nassau
Rating - 100%
29   0   0
Thank you though for the battery backup info, it was really an inside (Astoria) joke.
P/A told me the best supplemation for M/H is VHO. I'm planning on getting a PFO unit from them. Now I just don't know if I go w/T5 or VHO
 

meschaefer

One to Ignore
Location
Astoria
Rating - 100%
30   0   0
Thank you though for the battery backup info, it was really an inside (Astoria) joke.
P/A told me the best supplemation for M/H is VHO. I'm planning on getting a PFO unit from them. Now I just don't know if I go w/T5 or VHO


With all the work that he been going on since the summer, I hope we end up with a rock solid electrical system in this part of the woods.
 

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