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Energy Saving Lightbulbs

GreenNeedle

Member
Joined
19 Jul 2007
Messages
2,729
Location
Lincoln UK
Your T8s are the same as 'energy saving' lamps. They are only called 'energy saving' because they use less electricity to produce the same light as an incandescent. In essence they use as much power for 11W as a linear fluorescent on an electronic ballast.

Restrike is the major issue for our needs. In the house we want the light to be emitted in all directions so the spiral or double bend 'bulbs' are fit for purpose here. In our hobby we want to gather all the light and redirect it downawards. That means you would need a reflector that folows the piral redirecting light outwards and then another outer reflector redirecting the light downward. For that effor and cost then it would be pointless. This is one reason why the CFs we already use are not as good as linears as it is virtually impossible (for a reasonable cost) to manufacture a reflector that pulls the light from 1 side of the bent tube and then avoid restiking both tubes on the return.

The bulbs we use in the houses are not 'dimmer' than incandescents. They are 2700K which looks dim anyway. Foolish decision by the UK to use 'very warm white' instead of daylight. The 6500K ones in a house situation look as bright as the comparison statements suggest to me although like James says this can differ from bulb to bulb.

AC
 

Sarutobi

New Member
Joined
11 Aug 2009
Messages
13
Location
Okinawa Islands, Japan
Ah I see.

So how often should I change my bulbs? Once a year? I was thinking of getting a T5 HO fixture for my aquarium from a local pet store I live nearby. I just hope that stronger light will help my plants grow faster or so... Or probably get C02 to be put into my tank. With just the regular T8 light.
 

GreenNeedle

Member
Joined
19 Jul 2007
Messages
2,729
Location
Lincoln UK
Sarutobi said:
Ah I see.

So how often should I change my bulbs? Once a year? I was thinking of getting a T5 HO fixture for my aquarium from a local pet store I live nearby. I just hope that stronger light will help my plants grow faster or so... Or probably get C02 to be put into my tank. With just the regular T8 light.

The 6 month to a year 'rule' is a long standing one but was based on the technology of the time which was T8 or older and using magnetic (electric) ballasts (The ones with the seperate circular cylinder starter)

If using an electronic (not electric) ballast as all T5HO do then this rule is garbage. It is suggested that electronic ballasts with fluorescent tubes (including T8) will lose approx 5% over the first 40% of their life. T5HO life can be stated as much as 35000 hours so if we err on the conservative side and suggest their life is 20000 hours then 40% would be 8000 hours. 8000/8 hours a day = 1000 days. Nearly 3 years and that is conservative!!!

So in essence chuck the old 'replace tubes every year' rule in the bin. I would suggest buying quality tubes to start with though :)

AC
 

GreenNeedle

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Joined
19 Jul 2007
Messages
2,729
Location
Lincoln UK
No I am saying that T5HO manufacturers often state a life of 35000 hours which at 8 hours a day would mean it would last for 4375 days and that is 12 years.

However manufacturers will give the most attractive figures possible and in the latter years the tube will not be giving out much performance whilst using the same power.

Rather than use 35000 hours I said 20000 to be much more realistic in terms of reasonable light output. To me the life of the lamp is how long it is useful and not how long until the final lumen disappears.

However people want their lights to be peak over the aquarium and not faltering slowly and therefore replace them way before the tubes' life is ended. So if the tube on a modern electronic ballast only loses 5% of its lumens after 40% life then we can say that 40% life is between 8000 and 14000 hours. I would err more towards the lower end as I don't believe the manufacturers' optimistic statements :)

The manufacturer wants you to buy their product because it lasts the longest but charges a premium price for it. The retailer however wants you to buy the premium price product and then replace it much more often than necessary. If a 'golden rule' helps them out they are quite pleased to 'agree' with it :)

AC
 

dkm

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Thread starter
Joined
7 Jun 2009
Messages
208
Right my experiments are not going well. So......



My attention has turned to LED. This is what I am looking at http://www.electricity-monitor.com/evol ... -p-89.html

Now these are getting good reviews. Just ordered one to try. If it does not work out I can use it in my study ceiling light. As far as i am lead to believe these have a wide dispersal of light so being in the bresslein reflector should help direct all the light down onto my aquarium.

Lets see what happens!

Not cheap though!

Dave
 

dkm

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Thread starter
Joined
7 Jun 2009
Messages
208
Things are on the up.

My EvoLux bulb arrived today. First impression is wow!

It is bright. The 'eye test' was it was as nearly as bright as my MV set at 80w, brighter than a 60w incandescent standard bulb. I put one of each in my bresslein reflectors next to each other to get a side by side comparison. It came out really well. I would say color wise it has a slight yellow tinge to it but nothing to moan about. I know its not a definitive way of testing but to my eyes is somewhere between the 60w and 80w mark. A meter would be good to check it though. The light due to being more inset into the pendant than the MV has less sideways leakage of light and more light is focused downwards.

So if I a run three in my pendants that should equate to at least approx 180w above a 60G aquarium (3wpg). Hopefully should be enough. Only trying to grow plants under it, will it become apparent if it is good or not! So may try and get hold of two 6000k ones. Run the 3000k I have been testing in the middle and the two 6000k either side. Only time will tell.

After running it for 4 hours tonight the pendant is still cool and the bulb is only slightly warm. This is mainly due to the built in fan in the bulb. When ordering the bulb this was a concern. Would it be noisy with the fan but to my surprise it is very quiet indeed. Only just audible from point blank range. Coming from a marine background I (and my very understanding wife) are use to noisy ish aquariums! But this aquarium I want as silent as possible. So happy about this factor.


Pros:

13w power consumption each!
Cool running
bright
safer than mercury vapor and more 'eco friendly' (no mercury)
lasts >50,000 hours each!
less light leakage

Cons:

cost (£40 each!!!) can be off set by running cost
extremely low hum from fan

So to me the pros outway the cons. If plants will grow under them!

Now only need my aquarium to finally turn up. Been on order for the last 8 weeks. Lets see what happens.

dave
 
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