question for you plant guys on lights

[Hookup]

question for you plant guys...

in following along, i'm a bit confused... can you experts help?

it seems that for planted tanks you want high-output lights (i assume that refers to high PAR values?)

but LED's are debatable if they have high-enough output?

But T5HO's are the lights of choice?

But you don't have to change the bulbs till they burn out?  (which, doesn't that mean the PAR values fall off as well after the first 8-12months?)

I'm confused... (and sorry to the OP, this is likely way off topic...)

[charlie]

question for you plant guys...

in following along, i'm a bit confused... can you experts help?

it seems that for planted tanks you want high-output lights (i assume that refers to high PAR values?)

but LED's are debatable if they have high-enough output?

But T5HO's are the lights of choice?

But you don't have to change the bulbs till they burn out?  (which, doesn't that mean the PAR values fall off as well after the first 8-12months?)

I'm confused... (and sorry to the OP, this is likely way off topic...)

Maybe we should start a new thread.
Like the others sorry for the derailment.
The question is
how much does it fall off?
Does it fall off to significantly affect photosynthesis of the plants?
those answers will clear the confusion

[fischkopp]

Though no expert I will attempt an answer.  There is no need to go into technicalities. T5HO bulbs will loose in intensity, that is correct, but if memory serves me well it will still have around 75% intensity, maybe less, at their end of live. What does that mean for plant? Obviously they get less light energy, and will grow slower. And that is it already.

In "high light" tanks you have usually more than one of these bulbs running. Whereas the definition of high light is a quite personal thing. In the end it will depend on your tank (dimensions) and the plants you would like to have in there.

As for T5HO being the the light of choice, this is the case if you are thinking a bit about your budget as mentioned before. You can use any light source you like, but you need to be aware that some options are (a lot) more expensive than others. Another aspect to consider is also the light temperature/color. You will have more options and flexibility to adjust that to your liking if you use bulbs. In the end it depends what you want to do in your tank. I am just sharing my experiences.

[Hookup]

are there par values that you look for in planted tanks?

are T5HO's just cheaper than LED's so that's the main argument?

are MH/s used?



PS: Thx for the new thread/split... good idea.

[charlie]

are there par values that you look for in planted tanks?

are T5HO's just cheaper than LED's so that's the main argument?

are MH/s used?



PS: Thx for the new thread/split... good idea.

(1) par values for planted tanks will vary dependent on type of plants one desires to grow, that said it has being established that 30-40 micromoles @ the substrate will suffice to grow most of the low growing foreground light demanding plants.
(2) NO, the main argument is the statement that you need to change out T5 HO bulbs annually, which adds to the cost debate T5 HO vs LED - that teaching has being found to be not accurate by persons with tons of experience in the planted tank world, i only have a few yrs & a ton more to learn but have tested that theory & also found it to be inaccurate.
(3) MH has been & is still used.

[charlie]

(1) par values for planted tanks will vary dependent on type of plants one desires to grow, that said it has being established that 30-40 micromoles @ the substrate will suffice to grow most of the low growing foreground light demanding plants.
(2) NO, the main argument is the statement that you need to change out T5 HO bulbs annually, which adds to the cost debate T5 HO vs LED - that teaching has being found to be not accurate by persons with tons of experience in the planted tank world, i only have a few yrs & a ton more to learn but have tested that theory & also found it to be inaccurate.
(3) MH has been & is still used.

I should add , i`m no expert but a passionte planted tank hobbyist that does not mind sharing my views/expereince & is always subject to correction.

[Yams]

"but LED's are debatable if they have high-enough output?"

Depends on the LED's in question. Some are more powerful than others. Some are high enough intensity for Coral Aquariums, some are just for fish only, no plants. (also depends how deep the aquarium is, as I have read LED's dont penetrate the water that well.)

LED's that are used for high light planted tank though would be expensive. Pay for what you get. T5's are much cheaper in comparison.

Again, no expect but I use LED's and grow plants with no problems.

[wolfiewill]

Starting from the initial post (from Hookup): Any bulb will loose light output as it ages, and I agree (with fischkopp) that the drop off toward the end of a bulb's life is in the 75% range (I measure using a Lux metre). But I find that with light demanding freshwater plants that as the bulb ages the plants get 'leggy'. This is especially so with a single light sourced tank and stem plants, but also for the grass-like carpet plants which are supposed to stay short in the front and centre of the tank (Sagittaria and E. tenellus are my best examples of this). My experience is with MH and CF bulbs. I have jungle style designs in my tanks and a so everything explodes towards the surface competing for the dwindling light near the end of the bulbs life. So, I have to be vigilant and measure periodically and compare with previous readings to know when to replace my bulbs.

But it's complicated by the ballasts (with MH). Different ballasts provide different power regimes and a higher rated ballast will age an MH bulb more quickly than a lower rated ballast. I have two 65 gallon tanks (24" deep), each with exactly the same reflector and bulb combinations and initially the same age of bulb. Only the ballasts were different. Initially the light brightness from the two was very noticeable visually, and with experience, I realized that in each tank different plants grew well. In the end I got nearly 12 months with the bulb and the higher rated ballast before it needed changing, and 15 months with the bulb fed by the lower rated ballast. Lux readings were different (approximately 30%) throughout the time period.

I have only begun to experiment with LEDs and have been disappointed so far except for low tech, low light tanks. But I'm going to keep trying. I probably haven't got enough emitters. Switching to LEDs is a minefield. There is so many conflicting information regarding emitter quality and power ratios (watts/gallon). And online, everyone is an expert.

The conventional advise that the professional hydroponics growers give is that LEDs don't have the ability to 'punch' through to lower hanging leaves. They are advising T5 for short plants (shallow tanks?) and MH for tall plantings that require light penetration to lower leaves. I realize that they have different experience but it does support my own (and yes, very limited) experience. But some of the wisdom is probably extrapolatable to the aquarium experience. They don't advise LEDs (yet, anyway).

[Hookup]

Wow. 

Thanks for the info. 

I def learned a lot,