Whats the deal with T5's?

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Super_Blueberry

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I'm in the process of replacing my stock t8 fixtures to t5's. I was planning on starting off with four 14 watt bulbs (56 watts total), which on my 55g would bring me to the 1:1 ratio. Then I thought I might be able to replace 2 of the bulbs with some 28 watt HO's, and with the other 2 at 14 watts, I'd have 86 watts, closer to a 1.5:1 ratio. Now I have read a couple comments on other threads that the watts per gallon rule is essentially thrown out the window when using t5's, so I'm back to square one.

So what is the 'general' rule of thumb to lighting with t5's?
 
Depends on what you want to grow. How much maintainence you're will to put in blah blah blah... Normal output fixtures won't take to HO bulbs I could be wrong though. 4x HO would suit your needs IMO if you need more you have it if you need less take bulbs out.
 
Part of the switch is to get some separate ballasts for the HO bulbs installed if needed. From what I see, the fixtures I have can take two 14 watt bulbs or one 28 watt bulb ( which I assume is the same as an HO in this size from what I can find online). So I'll get a couple extra fixtures, take the ballasts out of those, and wire them in with another.
 
If you want to use HO bulbs, you have to get a HO fixture. Putting a regular t5 bulb in the HO fixture could burn it out quicker due to HO.
 
I'm in the process of replacing my stock t8 fixtures to t5's. I was planning on starting off with four 14 watt bulbs (56 watts total), which on my 55g would bring me to the 1:1 ratio. Then I thought I might be able to replace 2 of the bulbs with some 28 watt HO's, and with the other 2 at 14 watts, I'd have 86 watts, closer to a 1.5:1 ratio. Now I have read a couple comments on other threads that the watts per gallon rule is essentially thrown out the window when using t5's, so I'm back to square one.

So what is the 'general' rule of thumb to lighting with t5's?

The Watts per Gallon rule is mainly for T12 - T8 bulbs, it goes out the window with T5's, CFL LED's etc. See the charts in the link below which is a much more accurate way to gauge the light intensity you can expect ... thus what plants do best and would you need to dose CO2 to help control algae.

Hope it helps(y).

PAR vs Distance, T5, T12, PC - New Chart

BTW ... agree that T5's need a T5 fixture.
 
mohican said:
If you want to use HO bulbs, you have to get a HO fixture. Putting a regular t5 bulb in the HO fixture could burn it out quicker due to HO.

So the 'HO' isn't based on the wattage it puts out alone? I only ask because all the standard NO bulbs I've looked at in this size are 14 watts, and all the HO's are 24 watts. Other than that I can't find any difference....
 
I think the issue is with the ballast in the fixture. On a 55 planted I wouldn't run more than 2x54w t5ho unless you plan to use pressurized co2 at some point.

The most effective, simple, and cost effective route is to just scrap the t8s, modify the hood and run a 48" light across the top. Ebay has oddysea 2x54w T5ho fixtures for around $65 shipped.
 
So the 'HO' isn't based on the wattage it puts out alone? I only ask because all the standard NO bulbs I've looked at in this size are 14 watts, and all the HO's are 24 watts. Other than that I can't find any difference....

The way I understand, the HO's have a higher output ... meaning it uses more power and emits more light so higher wattage.

Most members that have T5's usually mention they go with the HO's.
 
jcolon said:
The way I understand, the HO's have a higher output ... meaning it uses more power and emits more light so higher wattage.

Most members that have T5's usually mention they go with the HO's.

So if a ballast is rated for two 14 watt bulbs, or one 28 watt bulb, and I put one 24 watt HO bulb on a ballast, I guess I don't see the problem IF the only thing that makes the bulb a HO is the increased wattage in that particular size.
 
jetajockey said:
The most effective, simple, and cost effective route is to just scrap the t8s, modify the hood and run a 48" light across the top. Ebay has oddysea 2x54w T5ho fixtures for around $65 shipped.

I've thought about that, but for $45 for the fixtures and the bulbs, I figured it's a cheaper way to start without having to modify the entire hood
 
I've thought about that, but for $45 for the fixtures and the bulbs, I figured it's a cheaper way to start without having to modify the entire hood

(2) 2-bulb fixtures /24" and 4 new full spectrum bulbs?

I'm pretty sure that you aren't supposed to run t5ho bulbs in t5no fixtures because of the ballast rating, it'd be overdriving it's capability.

The biggest concern is even if you do save a few bucks on a t5no setup, is it going to be enough for what you want to do? What type of fixtures are the t5's in? What kind of reflectors?
 
jetajockey said:
(2) 2-bulb fixtures /24" and 4 new full spectrum bulbs??

Two 2 bulb fixtures that can be rewired to a 1 bulb fixture capable of the same total wattage. So two fixtures with one bulb each. The second part of the equation is to take the ballasts out of 2 other fixtures and wire them into these. So now I have 4-28w ballasts running 4-24w bulbs in 2 fixtures. Yes it's going to be some rewiring, but these fixtures are designed to be rewired in different configurations.

The reflector is something I'm still working on. Don't know if I will take some polished metal and shape it to the hood, maybe take some white ABS which is basically all the original fixtures are.
 
Theres much more to this than watts. It's extremely likely that different bulb technologies, ie t5, t8, t5ho, have different operating voltages and currents. Crossing ballasts and bulbs could potentially end in damaging your bulbs/ballast, or worse, causing a fire.
 
Update: I made one hood retro last night. Neither ballast gets hot, and for now it's two 24w t5ho, no reflector currently other than the fixture itself. Defiantly a noticeable difference. I'm going to run one for the weekend, make sure there is no blatant issues, and if it goes good, I'll retro the second Sunday night.
 

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"HO" is for high output rather than normal output like avg. T5 bulbs. The normal 14watt bulbs will have a very short life span in a HO fixture. You can't mix and match at your leisure. "HO" fixtures run a little more $$ due to the "HO" ability. I feel you can get more with HO fixtures than regular T5 fixtures.
 
I just purchased fixtures; 4 exactly. I can take my canopy off separately than my lights to view my tank with top off. I found buying reflectors, ballasts, lights, etc. ran more money than just buying HO fixtures.
 
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