Using shorter bulbs on a t5 fixture

[danben]

Hi Guys!

So I've been setting up a 20gallon (tall) planted tank and was thinking of going higher tech (I'm getting a CO2 system and will be regularly dosing ferts) and I have some issues with lighting.

I currently have a single 15 watt t8 bulb (6500k) over the tank and either I could get another fixture to double up the lighting (found one cheap online), or I could go with another option.

I have a 48inch t5ho fixture lying around that holds 4 bulbs, and I was wondering if I could somehow rig it up to fit 22 inch bulbs without you know, the bulbs exploding or anything like that

If so, would it be worth it?

I'm just looking at growing a DHG carpet, amazon swords, cabomba, and just a random assortment of whatever I've got leftover in my tank (my LFS sells most plants as "assorted bunch plants" and figuring out what they are can be quite... difficult T_T).



TL/DR:
Can you use shorter t5ho bulbs on a fixture meant for ones twice their wattage?

[Mebbid]

You would have to change the ballast out and find some way to rig them up. I wouldnt recommend it.

[PassengerTN]

Even changing out the ballast won't work considering there's a 16" difference in bulb length. I'm sure you could cut it apart and move the end pieces containing the pins and such inward 8" each side to accommodate the shorter bulbs combined with a ballast change and possibly the pins but it'd be easier to just buy appropriate sized t5ho fixture.

Also if what I understood when I looked at using t5ho's in planted tanks, a single t5ho fixture needs to be atleast 24" from the substrate (suspended 7" above your 20T tank) in order not to be TOO much light.


Jesse

[ImACoolguy]

Unless you're an electrician I wouldn't do it don't want to set the house on fire because of a short in a bulb.


Caleb

[Mebbid]

Originally Posted by hensleyjk

Even changing out the ballast won't work considering there's a 16" difference in bulb length. I'm sure you could cut it apart and move the end pieces containing the pins and such inward 8" each side to accommodate the shorter bulbs combined with a ballast change and possibly the pins but it'd be easier to just buy appropriate sized t5ho fixture.

Also if what I understood when I looked at using t5ho's in planted tanks, a single t5ho fixture needs to be atleast 24" from the substrate (suspended 7" above your 20T tank) in order not to be TOO much light.


Jesse

I have 4 t5ho bulbs over my 40g tank that sit about 16" above the substrate and it works fine. You just have to be prepared for the high par.

[PassengerTN]

The two over my 55 is an algae growing machine, but it has no plants and is intended for my 75 saltwater tank that's not setup yet lol

Jesse

[Mebbid]

Originally Posted by hensleyjk

The two over my 55 is an algae growing machine, but it has no plants and is intended for my 75 saltwater tank that's not setup yet lol

Jesse

With proper fertilizers, carbon, and photoperiod they work fine.