150watt metal halide on a 30 gallon planted tank.

[nightster]

This tank has been running dual t8's and is about to get a major upgrade IMO. I was wondering how far away from the substrate should i start with the 150mh? I know i need to cut my light cycle back alot too, probably go from 8hrs to 4 or 5 to start.

[sunkenmetal]

damn dude lol

[nightster]

Its gonna be the light for the 40 once its set up. Just putting it to use for the time being...

[sunkenmetal]

Nice some serious light...

[Complexity]

Depends. Which algae are you wanting to grow? )

[nightster]

Depends. Which algae are you wanting to grow? )

The good kind...

[Complexity]

Are you fond of hair algae? It's the algae I associate most with excessive lighting, and CO2 won't stop it. Fortunately, H2O2 is cheap and does kill it.

Honestly, I think it's too much light for that size of tank, but if you go ahead with using it, then I'd put pretty high above the tank in order to weaken the light before it hits the tank. Maybe you can hang it from the ceiling so that it's somewhere around 12-18" above the tank?

[myjohnson]

No such thing as too much light....

More ferts and CO2.

Balance it out, that's all.

[fishman1]

yup with all that lighting keep up with your co2 and ferts I also agree that you should raise it up about 1-2 feet from the tanks top

[Complexity]

No such thing as too much light....

More ferts and CO2.

Balance it out, that's all.

I disagree. Because there are finite limits for other components in the equation, it is possible for the lighting to have too much light to maintain the balance.

CO2 most definitely has an upper limit if the tank has living animals in it since it is well known that too much CO2 is very deadly to fish and inverts. Further, the growth rate of the plants is an active factor in that balance, and you cannot push the plants beyond their growth rate capacity. For example, an anubias will never grow as fast as hornwort even if you give it excessive light, ferts, and CO2. The plant itself becomes a limiting factor in the balance.

In order to have "no such thing as too much light," it would require that it be possible to add an infinite amount of light to the equation and be able to maintain everything in balance in all levels of that infinity. But that's clearly not possible since there are limiting factors. As long as any part of the equation has a limit, then all parts are equally limited. Therefore, lighting is indeed limited which means there is, in fact, such a thing as too much light.

[ssrprelude]

I have a 150w MH over a 60p which is less than 20 gallons with no algae problems. Light sits only 8" above the water with a 6 hour cycle.

[eklikewhoa]

My old MiniM I retrofitted a 70w MH into the Mini-Solar... that thing is like 4g.

Blance is the key. It grew lush plants and the tiger shrimp were fine.

[myjohnson]

I disagree. Because there are finite limits for other components in the equation, it is possible for the lighting to have too much light to maintain the balance.

CO2 most definitely has an upper limit if the tank has living animals in it since it is well known that too much CO2 is very deadly to fish and inverts. Further, the growth rate of the plants is an active factor in that balance, and you cannot push the plants beyond their growth rate capacity. For example, an anubias will never grow as fast as hornwort even if you give it excessive light, ferts, and CO2. The plant itself becomes a limiting factor in the balance.

In order to have "no such thing as too much light," it would require that it be possible to add an infinite amount of light to the equation and be able to maintain everything in balance in all levels of that infinity. But that's clearly not possible since there are limiting factors. As long as any part of the equation has a limit, then all parts are equally limited. Therefore, lighting is indeed limited which means there is, in fact, such a thing as too much light.

Do you think EK and ssrprelude both have "too much" light also?

I agree with you in theory, but clearly I over stated the "no limit" on lighting to make a point.

Traditional notions, such as the wpg rule, is out dated and lives on by people not willing to go above it. Or worst yet....by people making statements based on limited knowledge on the assumption that anything not supported by their personal experience is not true.

Last time I checked....the sun punks a 150w MH so yeah, I don't think it's "too much".

And as such, that statement seems to be supported by EK and ssrprelude's personal experience.

[eklikewhoa]

Living within the rules and boundries. Only living in someone elses shadow.

[fwazeter]

150 MH is fine for a 30 gallon. We run a 150w MH bulb over a 17.7 gallon tank.

If anything, I might say you'd need to consider adding a little more oomph to the light. 250w MH is too much, but a few 36w compact flourescents would get you there.