So, I’m running a 30g tank, 36” long. Tank is 12” deep.
4” above the tank is a 4 bulb T5 (36”/39w bulbs).
Bulb brands are mixed now, Geissman and ATI (2 blue, 1 actinic, 1 coral plus).
Two lights run from 10am to 6pm, with additional 2 kicking in from 12 to 4pm.
Some of my montis are losing color in patches, and now a few sps are showing the same.
I have no idea if I’m beginning to kill corals from too much par, too little par, too much light time, or too little light time.
So, a few questions from a new T5 guy (yes, I’m reading about as well).
For such a popular lighting method there’s remarkably little ‘layman’s’ information about.
1. Is there a ‘general PAR’ reading for a generic 4 bulb setup at different depths? I understand each bulb is different, but assuming a quality bulb, is there an estimated par at 0”, 6”, 12”, etc?
2. In a 12” deep tank, lights 4” off surface, in general are 2 T5s enough light? Are 4 T5s too much?
3. Tied in with the above question, I’m running 2 bulbs for 8 hours. During this there is a 4 hour Period with 4 bulbs on. Is this too little? Too much?
4. I understand PAR is radiation and red/blue based and that lux is visual light and is green based, yet I’m reading of people using a cheap lux meter and performing a calculation to get a ‘sort of accurate’ PAR. Anyone done this or know of any info that backs it?
Thanks in advance.
I’d like to keep on the topic of PAR and the questions above and not have this spiral into a single discussion on where to buy LUX meters or such.
4” above the tank is a 4 bulb T5 (36”/39w bulbs).
Bulb brands are mixed now, Geissman and ATI (2 blue, 1 actinic, 1 coral plus).
Two lights run from 10am to 6pm, with additional 2 kicking in from 12 to 4pm.
Some of my montis are losing color in patches, and now a few sps are showing the same.
I have no idea if I’m beginning to kill corals from too much par, too little par, too much light time, or too little light time.
So, a few questions from a new T5 guy (yes, I’m reading about as well).
For such a popular lighting method there’s remarkably little ‘layman’s’ information about.
1. Is there a ‘general PAR’ reading for a generic 4 bulb setup at different depths? I understand each bulb is different, but assuming a quality bulb, is there an estimated par at 0”, 6”, 12”, etc?
2. In a 12” deep tank, lights 4” off surface, in general are 2 T5s enough light? Are 4 T5s too much?
3. Tied in with the above question, I’m running 2 bulbs for 8 hours. During this there is a 4 hour Period with 4 bulbs on. Is this too little? Too much?
4. I understand PAR is radiation and red/blue based and that lux is visual light and is green based, yet I’m reading of people using a cheap lux meter and performing a calculation to get a ‘sort of accurate’ PAR. Anyone done this or know of any info that backs it?
Thanks in advance.
I’d like to keep on the topic of PAR and the questions above and not have this spiral into a single discussion on where to buy LUX meters or such.
Last edited:
