Switching from 150 HQI Radium to 250 Radium on 16" deep aq.

[MisterP]

Ok guys I am thinking about switching from my 150 HQI Radium on M81 with a Cayman Sun reflector to the exact same reflector with 250 SE Radium on M80. Tank is 18"x18"16" with no other lighting.

To much light for a 16" deep tank hung 9.5" off water?

I want to switch because the growth is almost nil and I want to keep some more light loving sticks. The ones that REALLY like getting blasted with light. I just worry about my red dragon and a few montis. The few acans I have are already on the bottom.

Thoughts/advice.

[James77]

That is a lot of light for that shallow a tank(the 250 radium). More light does not always equal more growth?
What kind of flow do you have? What are your parameters like, and how stable are they? Are there fish in the tank and/or do you feed the coral?

[MisterP]

That is a lot of light for that shallow a tank(the 250 radium). More light does not always equal more growth?
What kind of flow do you have? What are your parameters like, and how stable are they? Are there fish in the tank and/or do you feed the coral?

I have an Mp10 and may add another just to randomize it a bit more.

Parameters are stable within a small range

Alk: 8-9 dkh
Cal: 440-480
Mg: 1320-1400
NO3: 0-2ppm
PO4: when I measure which isn't very often---20-30ppb on Hanna
4 gallon WC every week with ESV salt.
I dose KZ Zeostart, spongepower and Zeobak.
5mL of ESV Alk per day and 3 mL of Cal per day keeps me in my range.

Colors are fine, everything is healthy, very little algae as I only clean a light film off the glass 2 times a week and my 2 turbos and a dozen small stomatellos work hard to find food. Coralline is booming.


Livestock:

2 Clowns, 1 Freidmani orchid dottyback,1 peppermint shrimp all get feed often. I feed them once a day with a few small chunks of Larrys Reef Frenzy. I also feed them 7-8 pellets every day so they eat pretty well.


Everything is pretty good just growth isn't real fast. I've got a stylo frag thats only grown about an inch in 5 months. I've got a zoanthid colony on the bottom that has only produced 4 additional polyps in the same time frame. Some pieces seem to grow ok just not great. I've thought about more random flow but I don't really see how that will help as the flow now is enough to shake the polyps around pretty good.

I think I just need a little more light and it may be something along the lines of a 20% gain that get me where I want to be without blowing everything out.

Maybe this.....?
077febe5759a88c2dd64470c336eb0cf.png

Maybe I do a 250 W Hami 14K or an XM 20K with an e ballast like the Lumatek. More light just not Radium M80 light.

[MisterP]

Here is the graph of the 250 XM & Hami with the Radium 150.

2b96b5ac4a0749c454f138de3784b0f20000000.png

[stancfii]

That is a ton of PAR for that size tank. I switched from 150w hqi to 250w because of the color options, and I'm trying to sufficiently light a 40br with only one bulb. In a LA mini reflector, with a brand new Radium 250w (bulb about 9" off of the water) I was getting roughly 900 PAR under the surface of the water, and about 250-300 on the sand. That is also running the Radium on a 250w e-ballast, and not the spec M80. Your current setup should be getting you 150-200 PAR on the sand under the bulb, which is plenty. I'd increase the halide photoperiod before moving up to more wattage. If you still feel you need more after doing that for a few weeks, then I'd look into adding a strip of LEDs. FWIW, I was growing montipora on the sandbed with a 150w phoenix (less par than the radium) in a reflector that was 10-15% less efficient than yours (getting 100-150 par on the sand).