Acclimating to 400w mh question..

[glennr1978]

So marine depot has a sale going on and 250 and 400w radiums are the same price. I was thinking about moving up to a 400 on the sps side of my frag tank and since it didn't cost me anymore than a 250 I went ahead and did it.

My question is, how long should I run the 400 to start with? The tank is only 12" deep (I wanted the 400 for more spread) and is pretty much 3'x3'. I ran a 250w radium for 7 hours per day. I'm thinking 3 hours a day to start and working my way back up to 7 hours a day over the next month. Thoughts?

 

[Amphiprion]

It would be better for your corals to reduce the intensity rather than just the photoperiod. Reducing photoperiod would be akin to getting sunburned, but simply burning for a shorter time frame. There may be less damage that way, but the fact of the matter is that damage is still ocurring. It would be more ideal to reduce the intensity to minimize damage. Your better options include raising the fixture or using a screen-like material to block some incident light.

What kind of PAR increase are you looking at with your lamp/ballast combination?

 

[oscar.millan]

I would raise it and slowly bring it back down over time, assuming you're setup for that.

Also, as a side note I run my 400w MH for six hours and I don't feel I get any added growth beyond that point. I've played with 4 to 8 hours of light, 6 hours is the sweet spot for me.

 

[glennr1978]

Well, the "problem" is that I'm covering a large area 3'x3' (the tank is 6'x3') per light, and I feel like the SPS side of the tank could stand to have a little more light. Hence the reason why I went up to a 400w from a 250w.

The bottom of the reflector (LME) is 2' from the surface of the water so it's already up high. The lights are suspended so I could easily raise or lower them as needed. However, I kinda feel like they are already pretty high so I would rather not raise them anymore if I don't have to.

I've read from multiple sources over the years that reducing photoperiod and then ramping it back up over time is a good way to acclimate. Is this not a good idea anymore?

I would rather not use the screen method as I am constantly in the tank for something and I don't want to have to mess with moving screens all the time.

 

[glennr1978]

What kind of PAR increase are you looking at with your lamp/ballast combination?

I'm not chasing #'s specifically. I just feel like the SPS side of the tank could use more light. I'm running radiums in lumenmax elite's, fired by galaxy adjustable ballasts.

 

[glennr1978]

Also, as a side note I run my 400w MH for six hours and I don't feel I get any added growth beyond that point. I've played with 4 to 8 hours of light, 6 hours is the sweet spot for me.

Thanks for the info !

 

[Amphiprion]

You can successfully acclimate them by reducing the photoperiod, though it will still be more metabolically taxing compared to simply reducing intensity. Plenty of people have and still do it this way. It's your call either way.

 

[Peter Eichler]

Let me know your thoughts on the change. I've toyed with switching from 250w to 400w.

 

[BrentH]

I've used both 400 and 250radiums and the. 400 look way better IMO has a brighter blue tint then the 250s you'll like it.... Also I agree with moving light up u will deff fry your sps with just changing the bulb

 

[glennr1978]

Let me know your thoughts on the change. I've toyed with switching from 250w to 400w.

Will do.

 

[glennr1978]

I've used both 400 and 250radiums and the. 400 look way better IMO has a brighter blue tint then the 250s you'll like it.... Also I agree with moving light up u will deff fry your sps with just changing the bulb

Idk, the bottom of the reflector is already 24" from the water. I'm not trying to light the whole room, lol!

I've been running the 400w for a few days now at 3 hours per day and haven't seen any signs of any problems so far. None of the corals are bleaching at all. In fact, one little acro colony seems to be getting much brighter on the tips. However, I was already starting to notice it coloring up before I switched.

I think I'm only going to work my way up to 6 hours per day, and have the two lights staggered. That way heat will not be an issue with only one light being on at a time. It also allows me more time to work in the tank overall (there is enough light throughout the tank to see what I'm doing regardless of which light is on).

Btw, the 400w makes the 250w look dim by comparison. I'm running the 250w on HQI (which overdrives the bulb), and the 400w on the regular 400w setting. Even though there is less than a 100w difference between the 2, the 400w appears to be twice as bright .

 

[sirreal63]

Brightness isn't really related to PAR and the 250 on HQI doesn't overdrive it, it drives it correctly however the 400 watt is being overdriven as it is actually a 360 watt bulb. Use whichever one you like, there really isn't a massive difference in PAR, just enough that some acclimation is called for.