4 bulb t5 on 90 gallon enough for high light - The Planted Tank Forum
  • 1 Post By Hendy8888
LinkBack Thread Tools Display Modes
post #1 of 4 (permalink) Old 08-30-2020, 06:13 PM Thread Starter
Algae Grower
PTrader: (1/100%)
Join Date: Jan 2011
Location: CA
Posts: 16
4 bulb t5 on 90 gallon enough for high light

I have a 90 gallon 48"L 18"W 24"H with a 4 bulb t5 fixture about 8" from the surface of the water. I run two 6500k bulbs that came with the fixture (grow light fixture), 1 KZ Fiji Purple, and one Giesemann super flora.

Is this enough light to be considered high light, enough to grow dwarf hairgrass? It doesn't seem bright enough and I'm starting to think I should have went with a 6 bulb.

Anyone have experience with a 4 bulb t5 on a 90 gallon?
Shrimpz is offline  
Sponsored Links
post #2 of 4 (permalink) Old 09-12-2020, 07:45 PM
Planted Member
PTrader: (0/0%)
Join Date: Jan 2018
Posts: 259
I surprised you got no response. I have a four bulb over my 19" wide tank and it was enough light to grow anything, but I did end up adding a single T5 fixture in back just to make sure I had full coverage. The six bulb fixture was just a little too wide.

I would replace the bulbs that came with it, as fhey are usually junk, are you sure theyre not just standard T5s? Regardless, I would replace those two bulbs, try adding another Flora bulb and a Geismann Tropic is my suggestion.
mboley is offline  
post #3 of 4 (permalink) Old 09-13-2020, 02:20 AM
Planted Tank Obsessed
Hendy8888's Avatar
PTrader: (0/0%)
Join Date: Mar 2008
Location: Canada
Posts: 392
I saw your post but forgot to reply. I used 4 bulbs over my 90 gallon 48x24x18 so a bit shallower but the light fixture is 10" above the rim of the tank and It will grow anything just fine.

Now to be clear I have an 8 bulb fixture but only used 4 at a time back then. I found the stems in the back corners appreciated the outer most bulbs above them for half the photo period. Since your tank is only 18" this won't be a big issue. Here are a couple pictures to illustrate the 4 bulb at a time setup I used. Pics are of different bulb combos that I didn't run together but gives you an idea of the split between the 4 bulbs which would lower the PAR even more. Each 4 bulb setup ran for 3.5-4 hours per day.

Greggz likes this.

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Hendy8888 is online now  
post #4 of 4 (permalink) Old 09-14-2020, 02:02 AM Thread Starter
Algae Grower
PTrader: (1/100%)
Join Date: Jan 2011
Location: CA
Posts: 16
Cool thanks guys. It seems to be brighter now actually. Maybe the bulbs needed to burn in a little. I definitely need to replace the 6500k bulbs I got with the light. Was going to get Giesemann tropic, but no one seems to have them.
Shrimpz is offline  


Quick Reply

Register Now

In order to be able to post messages on the The Planted Tank Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Please enter a password for your user account. Note that passwords are case-sensitive.


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:


Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode

Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

For the best viewing experience please update your browser to Google Chrome