Can you have too much light?

[Rémi]

Hey,

I recently purchased a lovely 30 gallon tank at the auction that I plan to turn into a somewhat high-tech planted tank. I will be building a custom canopy for it with multiple fluorescent tubes and I'm wondering if I can have too much wattage on a planted aquarium?

I will probably install multiple t8 tubes or t5 tubes depending on cost/wattage. Should I put as much light as possible?

Rémi

[fischkopp]

I would use 4x T5HO 24W, that will allow to grow you anything, but anything between 2-4 bulbs is possible. If you go custom with 4 bulbs, make sure that you can switch two off separately as you may not want full intensity all the time.

[Rémi]

I would use 4x T5HO 24W, that will allow to grow you anything, but anything between 2-4 bulbs is possible. If you go custom with 4 bulbs, make sure that you can switch two off separately as you may not want full intensity all the time.

Is there a big price difference between t5s and t8s? That's the only reason I would hesitate to get t5s. I will be wiring it all up myself so I can have them all on seperate switches and will set them all on timers but why I not want full intensity all the time?

Also, where's the best place to get everything (ballasts, bulbs and reflectors)? I was thinking of home depot but was also recommended a more specific store for the t5s.

[BigDaddy]

T5 bulbs are more energy efficient, take up less space and typically produce more usable PAR than a similar T8 bulb.

The only time you can have "too much light" is if you aren't providing everything else the tank needs for healthy plant growth.  In high light, it doesn't take a significant deficiency in CO2 or ferts for algae to capitalize and take root.

Is this a 30 long or a 30 tall?

[fischkopp]

T5 bulbs are more energy efficient, take up less space and typically produce more usable PAR than a similar T8 bulb.

That's why you want to use T5.

I have never used any ballast (so far) so I can't give you any suggestion about those. But what works well for me are those Sunblaster light strips from the hydroponic store. Each strip comes with its on little ballast, bulb included. The advantage is that you can control and combine any number of bulbs in the way you wish.

[Rémi]

It's a 30 gallon long. 36x12x16.

I went to home depot today and they had tons of t8 fixtures for cheap (20$ for a 2bulb fixture) however they all come in 4ft lenghts which is too long for my use. I did however find a double t5 fixture for about 40$. Only 21 watts though?

(http://www.homedepot.ca/webapp/wcs/stores/servlet/CatalogSearchResultView?D=980441&Ntt=980441&catalogId=10051&langId=-15&storeId=10051&Dx=mode+matchallpartial&Ntx=mode+matchall&N=0&Ntk=P_PartNumber)

Is it right that a t5 will have more watts then a t8 of the same lenght?

This is the other option from the hydroponics store: http://www.sunlightsupply.com/p-12140-sun-blaster-t5-ho-fluorescent-strip-lights.aspx

It doesn't list the wattage but I have been told it's at 39watts. In which case I could get two (or more) of those instead of the 21watt t5s from home depot and have more light? Unless I can swap the 21watt bulbs for 39watt bulbs without chaning the ballast? The home depot lights are the cheapest but at 21watts per bulb it doesn't seem very strong.

What would be my best option?

[ray]

Bulbs cannot be changed as they will be underdriven.One is a T5 normal output and the 39W is a high output.Most people when referring to T5 are talking about the High Output.Also to optimize you need proper reflectors or else a lot of light is lost in restrike.To optimize bulbs should be on a quality individual reflector

Ray

[charlie]

Remi , here is something to consider the tank is only 16 inches deep, after a substrate bed you are probably looking at a final depth of approx 14 inches for the lights to penetrate, i`m of the opinion that a single 36 inch T5 HO ( 39 watt) light fixture with a reflector would grow pretty much most of the so called high light plants with the proper nutrient supplementation( Co2 & ferts as needed), the only concern i would have is the coverage of light front the back of the tank.
This only a suggestion,you can always add a second fixture later if it turns out to be a wrong/bad suggestion.
my 1 cent worth

[charlie]

Remi , here is something to consider the tank is only 16 inches deep, after a substrate bed you are probably looking at a final depth of approx 14 inches for the lights to penetrate, i`m of the opinion that a single 36 inch T5 HO ( 39 watt) light fixture with a reflector would grow pretty much most of the so called high light plants with the proper nutrient supplementation( Co2 & ferts as needed), the only concern i would have is the coverage of light front the back of the tank.
This only a suggestion,you can always add a second fixture later if it turns out to be a wrong/bad suggestion.
my 1 cent worth

I should add for clarification my theory is based on the light sitting very close to the top of the tank as opopsed to 4-8 inches off the top 
Regards

[zima]

While I don't have experience with short planted tanks, I know that the watts/gallon rule of thumbs is only a good suggestion. My experience is that once the tank is established and nice balance is achieved, you can grow anything in a so-called medium light tank. So in this sense, I'm with charlie, with the exception that I would build in 2x39w T5HO with good reflectors right away, but make sure they can be turned on separately. I would start the tank with only 1 turn on and see how your plants react. You might or might not even need the second one. But I would definitely not go to 3x39 T5HO - this will be too much light in my opinion.

[Rémi]

Hey,

I bought a Coralife fluorescent compact (Single linear, 24": http://www.bigalsonline.ca/Fish_Lighting_Light-Fixtures_Power-Compact_Freshwater-Aqualight-Deluxe-Series_10113281_102.html?tc=default). It's 65watts and was a great price but it's only 24'' (tank is 36'') so I was thinking of pairing this with a single 36'' T5HO.

I want sufficient lighting to get to the smaller ground plants in the front however I also want the tank to look nice and have the plants at the back of the tank as visible as the front ones. Any thoughts of whether I should place the longer T5 in front of behind the shorter 24'' FC?

[Toss]

You have to see it in action to decide. Keep your option open if you decide to switch it later on.