PDA

View Full Version : How to calculate the amount of light in my tank

Kymaro
08/23/2016, 07:50 PM
Majority information for lighting of the coral I buy is Low-Moderate-High. Seemed fitting to apply that to bottom-middle-top of tank, I'm interested in learning how to determine a more accurate placement. I've seen lots of charts giving "%" at various areas of the tank but nothing about how they came to those light percentages. Is there some formula that I could use to be more accurate.

46 g with glass top

36" x 12" x 21" (16" at center of bow)

The light sits about 2 inches off glass top and runs 33" across top (centered both front to back and side to side.
Ron Reefman
08/24/2016, 04:13 AM
With that 46 watt fixture, you won't have to worry much about having too much light. Look at other fixtures in the market. Most of them are 180 watts or more if they are bigger.

Your fixture (low wattage) and your tank (at 21" tall) will be OK for fish, soft corals and some easy lps corals.

The only good way to know how much light you have is with a PAR (Photosynthetically Active Radiation) meter, and they aren't cheap $200-300). Look around your local club or an LFS an see if you can borrow or rent one. I've tested low wattage systems like yours or Current Orbit or Marineland leds and they are all meant for shallow tanks of 12" to 18". So at 21" you are pushing the envelope.
Kymaro
08/27/2016, 04:50 AM
Thank you, I'll be putting a new light (180 watts) on my wish list. I would like, someday, to enjoy the company of more challenging corals but as of now I am staying with the "easy" care levels as I continue to learn so much about water currents, maintenance and lighting requirements, the list goes on...

I will keep in mind my light system is lower than average. Thank you, this will be helpful.
Ron Reefman
08/27/2016, 05:36 AM
You are welcome.

Your approach to keeping things easy for now while you learn is very admirable! It took me 3 years with a 30g tank and 3 years with a 75g tank before I felt I knew enough to get really crazy with difficult stuff. But then I didn't know about RC and there was no local aquarium club in my area when I started.
Reel North
08/27/2016, 05:47 AM
If you really want to know - borrow a par meter. Then you can look up the par recommendations for each type of coral.
Kymaro
08/27/2016, 07:43 AM
If you really want to know - borrow a par meter. Then you can look up the par recommendations for each type of coral.

Thank you, I plan to contact my LFS on Monday to see if they have one to rent.
Ron Reefman
08/27/2016, 10:48 AM
If you haven't looked before it might be worth looking at local clubs near you and see if a member has a PAR meter. I loan mine out a lot and only ask for a small frag as payment!
WhiskeyCoffee
08/27/2016, 11:24 AM
If your LFS doesn't have one, I know of two websites which will allow you to rent one for about $20 to $25 a week. The only downside is they charge you over $300 upon rental for a deposit and then once it's returned, they refund the deposit less the rental fee.
Kymaro
08/27/2016, 03:49 PM
If your LFS doesn't have one, I know of two websites which will allow you to rent one for about $20 to $25 a week. The only downside is they charge you over $300 upon rental for a deposit and then once it's returned, they refund the deposit less the rental fee.

Ouch, that's sharp! I think if I can't find one to borrow as a reasonable price I can continue learning through experience. Later when things get more intense and there is "slim to no" wiggle room for guess work it will be worth the price. Unfortunately with me and my habits if I'm going to come up with the money like that to just borrow I'll probably just end up buying :lol2:
WhiskeyCoffee
08/27/2016, 06:09 PM
It's steep but like I said, it's just a deposit. The company is taking a huge risk loaning them out so it's understandable.
Reel North
08/27/2016, 08:21 PM
I'm seriously considering buying one to rent out.
WhiskeyCoffee
08/28/2016, 02:42 PM
I'm seriously considering buying one to rent out.

Do it, I'd rent it! :p
Ron Reefman
08/28/2016, 05:25 PM
I'm seriously considering buying one to rent out.

Are you in Hamilton, Ontario? My dad grew up on a farm in Stratford, not far from there, eh.
Kymaro
08/30/2016, 04:45 AM
Do it, I'd rent it! :p

I'm seriously considering buying one to rent out.

I'd rent it too! I'd even take a vacation to come get it..LOL