T5 hybrid question

rcpalmer1 · Dec 9, 2017

I have a 2x2x4 120gallon tank. I currently have a Kessil ap700. In the middle on top of my rocks 6" below surface is 250 par. 6" from bottom is around 150 par and around 100 par on the bottom. I have a lot of shadowing. I have about 60 corals, most all lps. I was looking at adding the 36" T5 hybrid that BRS sells. I am not sure how much that will raise my par. I don't want to kill what I have but. Not sure if this will help increase growth. I am interested in all comments.

GBRsouth · Dec 9, 2017

Take par readings of your tank now. Then when you add the t5's you can adjust down the brightness of your kessil to achieve similar par readings to what you now.

Daniel Waters · Dec 9, 2017

I'm not certain which fixture you are referring to, but if it's the aquatic life t5 fixture that you can mount your existing LED's in to, you should watch the BRS video as they give their par numbers for 4 blue plus bulbs. Mounting height and type of bulbs will impact your numbers also, but I think a general range of 25 to 40 par PER BULB might give you a very general idea for now (25 would be the lower part of the tank and edges and 40 would be for higher up in the tank). In my tank, i run 4 T5 bulbs and i only get about 15 to 25 par per bulb but i run my lights fairly high off the water (like 13"). Regardless, I think you would definitely want to fine tune everything using a par meter but you definitely would need to decrease your AP700 intensity level to compensate for the added light from the T5s. I would err on the side of going too low and then adjusting your led intensity each week to where you want to get to.

Besides par changes, the T5's are going to reduce your shadowing tremendously. Also, the shimmer from the AP700 will be muted somewhat from the diffuse lighting of the T5's. I actually prefer the shimmer with t5's versus LED alone as I find it a bit much on its own. As far as growth, I'm not sure you will see more growth supplementing with t5s. If you have larger corals that begin shading themselves or do not get enough light on their undersides (i.e. large branching acropora), then T5s will definitely help get light to all areas due to its diffuse nature versus point source LED lights.

All in all, I prefer my led / t5 hybrid setup to just led alone. I think you will be pleased, but you may have to spend a bit of time figuring out what bulb combination you want to use to get the visual look you want. There's plenty of posts to be had on bulb choices, so you shouldn't have any trouble figuring that out with a little bit of reading and discussion.

rcpalmer1 · Dec 10, 2017

Daniel Waters said:
I'm not certain which fixture you are referring to, but if it's the aquatic life t5 fixture that you can mount your existing LED's in to, you should watch the BRS video as they give their par numbers for 4 blue plus bulbs. Mounting height and type of bulbs will impact your numbers also, but I think a general range of 25 to 40 par PER BULB might give you a very general idea for now (25 would be the lower part of the tank and edges and 40 would be for higher up in the tank). In my tank, i run 4 T5 bulbs and i only get about 15 to 25 par per bulb but i run my lights fairly high off the water (like 13"). Regardless, I think you would definitely want to fine tune everything using a par meter but you definitely would need to decrease your AP700 intensity level to compensate for the added light from the T5s. I would err on the side of going too low and then adjusting your led intensity each week to where you want to get to.

Besides par changes, the T5's are going to reduce your shadowing tremendously. Also, the shimmer from the AP700 will be muted somewhat from the diffuse lighting of the T5's. I actually prefer the shimmer with t5's versus LED alone as I find it a bit much on its own. As far as growth, I'm not sure you will see more growth supplementing with t5s. If you have larger corals that begin shading themselves or do not get enough light on their undersides (i.e. large branching acropora), then T5s will definitely help get light to all areas due to its diffuse nature versus point source LED lights.

All in all, I prefer my led / t5 hybrid setup to just led alone. I think you will be pleased, but you may have to spend a bit of time figuring out what bulb combination you want to use to get the visual look you want. There's plenty of posts to be had on bulb choices, so you shouldn't have any trouble figuring that out with a little bit of reading and discussion.

Thanks that is what I am looking for. This will give me 200 at the sand and400 on top. I can adjust down from there.

LV3 · Dec 10, 2017

I have the same sized tank and an AP 700 with the aquatic life T5 retrofit fitxture. I run blue+ and actinic bulbs and will tell you that for LPS, the T5s alone are sufficient. I have to turn down the Kessil to 1% and find that at that intensity it adds ~20 PAR on the sand bed directly below the LED. That’s with a correction factor of 11%. I have the fixture mounted about 15” above the water line. Hope that helps.