400 v 250 Metal Halide for 300 gallon tank

Biosphere

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Need some advice. I have a 300 gallon tank (8 feet long x 2 feet wide x 30 inches deep) I had 2 400 watt metal halides and a 250 metal halide halide between the 400’s . One 400 metal halide ballast died and I replaced it with LED. Now I’m experiencing die off in my coralline algae under the Led and my corals don’t seem as happy. So I want to upgrade and change my lights. I was thinking of getting 2 Hamilton Cebu 48 inch lights which has 2 250 w metal halide and T5 bulbs. So then I would have 4 250 w metal halides. But I’m wondering if I should go for 400 w instead of 250. Currently in my metal halides I use 14,000k. I have mostly fish but I want to move into more corals and sps corals. What’s my best long term bet? 250 or 400 of something totally different that I’m not considering! Thanks!
 
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jda

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I use 250w HQI, which is a compromise, but not much of one. They run at 330w on m80 ballasts and some bulbs like the 14k Phoenix and 20k Radium have as much output on real m80 as on a 400w ballast.

The Giesemann line of bulbs are HQI too.

All of that said, regular 250w bulbs are fine if the reflectors are made to penetrate a bit. If choosing 250w, get electronic ballasts and the new 20k Hamilton bulbs which were made to look like 20k Radiums but don't need HQI ballasts and also do not get nearly as hot.
 

Ancient Mariner

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I have 2 400w MH over a 40” wide 24” deep tank. The top of my rock work is about 15” from the bulbs. I can only put corals with the highest light tolerance there. On the other hand I have lower light requiring Acropora growing at the bottom of the tank. I like it like this. However I have difficulty with Cyphastrea, favia, and other low light corals.

So, I’d map out a general stocking plan and choose the wattage that would allow for you to fulfill your wish list. If you mount the bulbs pretty high a 400w bulb still might allow a good variety of light intensities. If you mount low and want some low intensity corals, a 250w might be better.
 

njreefkeeper

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I think it all depends on what you’re comfortable with. I’ve been running halides for 20 years (both 400 and 250 watt Radiums). On the right ballast, the 250 watt Radium in the right reflector puts out just as much par as the 400. That aside, a 250 watt bulb will put our less heat, allow for easier light acclimation. At 24” wide tank, 250 with t5’s is more than enough to grow anything you wish.
 

jda

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Below is a chart of 250w 20k Radium on m80 next to 400w 20k Radium on 400w - 85 to 93 PPFD, so within 10% with an energy savings. I don't know if all bulbs do this, but I imagine that it close... Phoenix 14k on HQI is also 85.

If you choose well and don't overpower your tank, the electrical costs will not be any different than running similar LEDs or T5s to cover the same area well. For me, that is 250w HQI.

Screen Shot 2022-01-19 at 8.29.10 AM.png
 
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njreefkeeper

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Below is a chart of 250w 20k Radium on m80 next to 400w 20k Radium on 400w - 85 to 93 PPFD, so within 10% with an energy savings. I don't know if all bulbs do this, but I imagine that it close... Phoenix 14k on HQI is also 85.

If you choose well and don't overpower your tank, the electrical costs will not be any different than running similar LEDs or T5s to cover the same area well. For me, that is 250w HQI.

Screen Shot 2022-01-19 at 8.29.10 AM.png
I don’t even know if they make the Phoenix anymore. And the Phoenix is a double ended HQI whereas the radium is (to my knowledge) the only mogul based HQI. I’ve run the 250 watt Radium on both the Bluewave 7 M80 ballast and on the “HQI setting” of a switchable ballast like the old Galaxy and currently available Lumatek. The M80 drives the bulb to spec and it easily gets over a year of life when run properly. If you can find an M80 ballast the look simply can’t be beat...crisp white with a hint of blue.
 

YOYOYOReefer

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the radium bulbs 400 watt are not "hqi" thats the ballast that would be HQI ballast like a m80 on a 250 radium or pfo/son of agro overdiving 400 watt radiums is what they are referring to. i was just informed on a different thread that somewhere in time they changed the manufacturing of the radium 400s and the new ones are not safe to overdrive. Im not really too concerned i still have 44 bulb changes worth of bulbs in my reserves. but i did just change one tank over to radion 5 leds so i will only be going thru 6-7 bulbs a year now. Why whould they change it, do that many people really run leds vs halides these days?
 

jda

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There has been quite a few MH bulb changes in the past few years... dual arc, Hamilton and Giesemann with new lines. I don't know for sure about why Radium did - this is a popular general purpose bulb in the EU that just happens to work well for our hobby. Outside of the Radium, the new bulbs have more output and less heat, which is good.
 
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YOYOYOReefer

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Ya , funny how i got g5 radions xr30blues a couple weeks ago, first time ive had to do homework on heating my display tank lol, its mainly been about fans and chillers. lol... i have been getting by with a 200 watt heater on a 600 gallon system with just the tank lights and a 250 fuge runnign reverse hours. i ended up going with the IM Helio heater setup for the tank with the leds.
 

njreefkeeper

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the radium bulbs 400 watt are not "hqi" thats the ballast that would be HQI ballast like a m80 on a 250 radium or pfo/son of agro overdiving 400 watt radiums is what they are referring to. i was just informed on a different thread that somewhere in time they changed the manufacturing of the radium 400s and the new ones are not safe to overdrive. Im not really too concerned i still have 44 bulb changes worth of bulbs in my reserves. but i did just change one tank over to radion 5 leds so i will only be going thru 6-7 bulbs a year now. Why whould they change it, do that many people really run leds vs halides these days?
Very true. And overdriving the Radium 400 on and HQI 400 watt setting or super lumen setting kills the bulb life span...reducing it to about 6 months.
 

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