Glass lid and light

[candymancan]

Par is just so confusing.. and kinda stupid if you ask me... I say put a bright light over the tank that's got at least 1 6700k light and the rest pink and your plants will grow so fast you don't know what to do with them... and yes I have red plants in my tanks that require high lighting... Which I was able to grow and keep red/pink using regular T5's normal outputs and a couple plant grow T8'S..

As for glass and acrylic tops taking away light... You don't need a par meter to tell you that they do... Take your glass top move it back and forth from under your light in your fish tank (assuming you have a light that rests above the water like mine) and youll see the slight shading over the plants or wood or what not the glass does.. I have tried this with my 10g bowfront and its LEDS that came with the tank.. I moved the acrylic top back and forth and Its pretty noticeable that the top does reflect lighting.. You can even see the ceiling light up a little, same goes for my 44g Pentagon which is using Power Compacts.. I can see the slight shading over my plants and driftwood by removing my glass top and putting it back over.. I would say its about a 10-15% reduction in lighting but it isn't enough to justify keeping your lid off your tank and risk your fish jumping out..

As someone who is an amature astronomer and deals with telescope mirrors which refract and reflect lighting which is a lot more complicated then any of you/us fish tank people will get involved with... I will tell you this... dust and water stain films on the glass... or what not wont have much effect AT all when it comes to growing your plants.. We in astronomy come across dusty reflecting mirrors all the time or mirror covered in dried up morning dew and so forth and it doesn't affect the amount of light your mirror can see and reflect into your eyes from space which is why you you never clean them... Cleaning the mirror's is actually worse because of the micro scratches that get put into the mirror's that actually affects the light capturing more then dust will.

 

[clonitza]

how do you get that all white background for the photo no see through tank back or sides

The tank is 40cm away from the wall, no background was applied to the back glass.

Regarding the lid, I couldn't live without it, all my fish are jumpy, I've lost a lot of them before adding it and I won't go back, I can always increase the light intensity with reflectors or by adding another bulb.
The evaporation is also high without it cause there's a difference of 5 degrees between the aquarium and the room temperature.

Simply placing a light over an aquarium will not guarantee that your plants will thrive – it needs to be of the right type ...

For sure those 1000 led lamps nobody can live without ...

Cheers,
Mike

 

[dw1305]

Hi all,

Par is just so confusing.. and kinda stupid if you ask me... ... and yes I have red plants in my tanks that require high lighting... Which I was able to grow and keep red/pink using regular T5's normal outputs and a couple plant grow T8'S...... I would say its about a 10-15% reduction in lighting but it isn't enough to justify keeping your lid off your tank and risk your fish jumping out.

I definitely agree about the lid, I can find quite enough ways of killing the fish without adding another one, and I will always use a cover.

I don't think that any-one is arguing that all light sources are equal in terms of their out-put of photosynthetically active (usable) radiation (PAR/PUR), but it isn't as simple as saying that chlorophyll absorbs light in the red and blue spectra and reflects it in the green wavelengths.

The argument would be that most colour temperatures of white light (from even fairly modest wattage fixtures) produce enough PAR to exceed the <"light compensation point"> (LCP) of most plants. This is largely to do with the <"accessory pigments"> in the chlorophyll molecule, which will harvest different wavelengths of light from <"chlorophyll a">.

There is a more complete description in Clive's post here: <"Do T8 lights really degrade..."> or in Kirk's <"Light and photosynthesis in aquatic ecosystems">.

Once we are above LCP the major limiting nutrient for most aquatic plants is inorganic carbon (CO2), so rather than adding more light you need to add more CO2, and as you add CO2 the plants LCP will actually decrease. Light drives photosynthesis, and if we have non-limiting nutrients (including carbon) we can acheive very high growth rates. This was the reasoning behind the development of <"Estimative Index (EI)">. This then leads to the statement that there aren't any high light plants, there are just plants that have a higher CO2 demand.

Problems arise when we have a bright light source in a situation with low nutrient (including carbon) levels, this is partially to do with the <"damage caused by the excess energy from the incident radiation">. I'll leave the rest of this argument to some-one else, as I'm not a CO2 or EI user, although many use it successfully.

Personally a lot of PAR just means I have a larger plant mass, which I keep in slow active growth via the <"Duckweed Index">. It is a KISS solution and doesn't have the "bells and whistles" of EI, but I'm not an aquascaper, so it suits me.

cheers Darrel