Considering dumping halides and switching to halides??

[stancfii]

I'm currently running 3x250w Radiums over my 180g tank, with a supplemental DIY strip of Cree RB LEDs. Heat isn't too much of an issue (3 degree swing from 78-81 each day) with NO chiller. I'm getting pretty good SPS growth, but wonder if I could get better by stabilizing temps more. I've been giving thought to dropping the 3x250 and going to 2x400 Radiums. I have LumenArc 3 minis right now, and if the 400w Radium would fit in it, I could raise them up a few inches to keep the heat a little further from the water. My main concern is shading and distribution by going from 3 to 2. The 400w Radiums would more than likely be run on some sort of select-a-watt ballast. Any of the other old-timers here know if a 400w bulb will fit in an LA3mini or if I'd get good coverage? If I can raise them high enough, I could slip in a pair of classic VHO actinics (my real motivation?? Haha). Bulbs are currently 8" off the water, by could get them up as high as 12-18" with my open-top canopy.

 

[sirreal63]

If your temps are fluctuating between 78 and 81 every day, the same fluctuation, that is stability. A couple of questions.

Why do you expect 800 watts to cause less fluctuation than 750 watts?

What led you to believe that by reducing the temp fluctuation you would get better growth? (I have little doubt that something may be written out there, there is all kinds of rubbish written on reef tanks. I would like to read it.)

 

[stancfii]

Hey Jack, I was hoping you'd chime in! The wattage would be a wash, but being able to have the lights higher above the tank would prevent some of the heat transfer. I've never really read anything to prove that the temp swing would cause corals not to grow as well. I have talked to a few guys that farm SPS frags that say they keep their temp at a stable 78 degrees (plus or minus .5 deg). Both grow SPS like weeds with amazing colors.

 

[sirreal63]

There is nothing wrong with your current setup, it is actually ideal. Those swings are closer to natural than trying to keep a constant steady temp. There is no part of any reef where the temp is exactly the same, all of the time.

I wouldn't change a thing, you won't be gaining anything and may lose the ability of the coral to adapt. Right now they are acclimated to your daily swing, this is good, it allows them to better handle any issues like electricity being off and a drop or rise in temps. It is a huge risk to try and keep a steady, unchanging temp, the corals will become acclimated to no change and have a harder time when something happens to cause a change.

You won't be gaining light for the corals by going to two 400's and raising them, the Par drop off will be greater than 3-250's. You may actually lose Par. If you want to see your corals grow faster, slowly increase their food.

 

[Ron Reefman]

I'm with Jack. I don't see a 3 degree temp swing as a big deal. Getting coral to grow "like weeds" has a lot more to do with flow, water quality and feeding (food and supplements) than with lights (given the lighting you are already using).

It seems people always go to lights as the first thing that needs to change if they aren't happy with their coral growth or health. If you have terrible lights, then yes, that can make a big difference. But you have what should be a very good lighting system.

I had 2 250w and 2 150w MH and 4 3't5's over a 180g and corals did very well. I changed to all leds because in SW Florida, heat in the house was an issue. I have a 1hp chiller so water temps were not an issue. The leds grew coral just as well for me. IMHO, lights and small temp fluctuations are not the cause of your potential coral growth issues.

 

[d2mini]

I agree with Jack. Stick with what you have.

If I was to add anything or change anything, it would be to supplement with T5, either in place of the LED or additional.
Reason being... more light spread.
Right now you are using two contrasty light sources.

 

[stancfii]

Thanks, guys! It is a great lighting system and my corals are doing really well--just always looking to make some sort of improvement. Can't help but tinker! I think I may look into a pair of supplemental T5s for better light spread.

 

[Nanook]

You've got the best combination at present!

 

[sirreal63]

Don't overlook coral nutrition. The days of believing that corals only need light and fish poop needs to go away. Like all living creatures, proper nutrition is vital for growth and overall health. We will never be able to replicate the amount of food available in the reef but we can do more than light and fish poop. One thing to remember, as light increases so does the need for nutrition.

 

[stancfii]

I agree completely. The past few months I've been running higher ALK (from 7.5 to 10.0dkh now) and higher nutrients (took GFO offline). Growth took off immediately.

 

[jda]

Do you have any fans over the tank or sump? Just a few simple fans on when the lights come on can stave off the vast majority temp swings - not all, but most. A box fan over the top of my open-top tank in Missouri with 98 degress and 100% humidity would keep my swing less than one. You will evap more water, though.

 

[gcarroll]

Another thing to think about is the 250w Radium when used on an HQI ballast, is not far off the performance of the 400w Radium. In fact I like the 250w better. 3 - 250w > 2 - 400w when it comes to output.

 

[gcarroll]

Also like to add that the 250w Radium has a longer life span than the 400w Radium.
Radium 250 is rated at 270w and is recommended for a HQI/M80 ballast
Radium 400 is rated at 360w and is recommended for a pulse start ballast (which I have never met anyone running them on that ballast) This is why when you run them on a 430w HQI ballast, they are being way overdriven and need replacement every 9 months.

 

[stancfii]

Thanks for all the advice! I have an inkbird controller that kicks on the fans when the water hits 80 degrees and turns the heater on at 78, but will see if I can plug them in to come on with the halides. I'll stick with led supplements for now, because of the lesser wattage and heat. A long strip of leds with no optics seems to get me about as good of spread as the t5s I was using on my 40br.

 

[tkeracer619]

Are you using an m80 ballast?

A few years back the 400w radium bulbs construction changed a bit and the newer bulbs don't seem to handle the 430w ballast that well anymore. Not many people are running that setup anymore though.

The temp swing is not an issue. I prefer a temp swing in my sps tanks, IME the tank is less sensitive to changes when it has a daily swing. My fully stocked 360 with 16" diameter sps colonies had a 7deg daily swing. Corals grew like weeds.

 

[Tubeworms]

How active is the life in your sump? The more bugs the better. Their eggs and offspring will feed your coral growth far better than any off the shelf suppliments.