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reef_dude76
09/30/2017, 06:13 PM
Hello all!

Have a question about PAR and SPS corals. I've been out of reef keeping for 4 years and just recently got back into it again. I've got a standard 20 gallon tank (not long) with an ATI dimmable Sunpower 4 bulb T5 fixture. I just got done taking readings with my Apogee meter and surface reading is 400, reading at the top of my reef structure (roughly 3/4 the height of the tank) is 290 and reading at my sand bed is 175-190. I don't remember what the general target PAR readings are to keep SPS? I'm in the process of programming my light fixture and am trying to get an idea of percentage of power to run each of my two light channels at so that I have enough photosynthetic energy reaching my corals but not too much to bleach them. Bulbs are two 10k and two actinic, all bulbs are 24w.

Thanks for any and all input!

Cheapreef
09/30/2017, 06:37 PM
Those levels should be fine, I'm running 600 ish just below mid tank on my 21 gal cube.

reef_dude76
09/30/2017, 06:46 PM
Forgot to mention that the fixture is 5" above the surface of the water.

Cheepreef how deep is your 21 cube? I wouldn't think it's much shallower than mine?! I'm about 260-280 at the midpoint of my tank. Should I drop the fixture an inch or so to boost the light penetration/levels?

Wiskey
10/01/2017, 01:52 AM
Those par readings seem fine, especially since t5 spread the light so well.

The bigger concern in a tank that size is nutreant management. There are many great strategies the best results come from choosing one, sticking with it, and monitoring its effectiveness by something like the Hanna Ulr meter.

Whiskey

reef_dude76
10/01/2017, 09:15 AM
Right now I have an Eshopps nano HOB over flow that delivers water to a 10 gallon that I've converted into a simple sump. Water drains into the main chamber that holds a Reef Octopus 110INT skimmer, flows through a bubble trap to my return pump chamber and back to the tank. Flow is about 200-230 gallons an hour. I've got two Sicce voyager nano stream pumps in the tank controlled with a Sicce wave surfer. I've got a Tunze osmolator that I'm planning to add for auto top off. And I'm thinking of adding a Reef Octopus kalkstirrer/reactor and running my auto top system through that.

Cheapreef
10/01/2017, 11:02 AM
Forgot to mention that the fixture is 5" above the surface of the water.

Cheepreef how deep is your 21 cube? I wouldn't think it's much shallower than mine?! I'm about 260-280 at the midpoint of my tank. Should I drop the fixture an inch or so to boost the light penetration/levels?

It's a 18" cube with about 15" WL after the small amount of sand and the 1" below tank top WL.
I don't think I would drop it, I would run it as is for now see how it does. I would think being T5 havd having the spread you wont need as much PAR as LEDS.
BTW I run my tank with over saturated Kalk (20ml vinegar with extra 1/2 TSP) as all my top off water, helps keep the PH up and avoids the use of 2 part. But that means I'm carbon dosing so it's a balance.