Kessil AP 700

vareefer1979 · Jun 8, 2026

Hello, what is most common light intensity for single Kessil AP 700? Tank size standard 75 gallon 48L x 18.5W x 21H. The light fixture is mounted 13 inches above water line, centered over tank. I currently have it ramping up to 35 percent max from 1-6 pm then slowly ramps down to cut off at 11pm. Tank currently is LPS/Zoas/Mushrooms all just added over the past 2 months. I do not have par meter. I have watched the BRS video with par meter reading, but just wondering what others are setting the Kessil AP700 or apx9 intensity. I have been cautious the light intensity has all of my LPS are relatively low light corals: acans/favias/blastos which are currently doing well on low frag rack near sandbed.

Gumbies R Us · 2026-06-19T07:37:00-0400

#reefsquad

A_Blind_Reefer · 2026-06-19T09:08:10-0400

I ran these lights on several tanks over the years. All mixed reef, and all with supplemental power compact or t5.

The first tank was a similar sized tank as yours (narrower and deeper though). It had a canopy, so the ap700 was only inches above the water and had two power compacts.

I’m just mentioning that as every ap700 I’ve used was running 100% intensity and had supplemental lighting. While my tanks were mixed reef, I had everything you listed in them and all loved the lighting.

At the height you’re running at I would run them much hotter than you’re asking. If it were me I’d start at 60% and go from there.

Remember these lights are pretty old (I’m guessing you picked them up used) and may not be as powerful as new depending on hard of a life they had. Great lights though.

Rocks reef · 2026-06-19T09:34:03-0400

@A_Blind_Reefer is spot on! You will want the intensity to be pretty maxed out unless you run supplement lighting in front and back.
Even the BRS video stated that over an area 40x20 at 18” depth you will only be averaging less than 100 PAR since the 75g is deeper. Also, those numbers are directly under the light pucks. The outer edges barely saw 70PAR, even less. For example, I had a 40 breeder 36x18x18. I was running two Kessil a360x at 75% just to get 200 on sandbed directly under the lights. The ends of the tank and front/back was probably 100-125. It wasn’t until I added Meridian edge bars front/back that I was able to get an even 200-225 everywhere on the sandbed.
I love Kessil for the color and shimmer, but you need more than what is recommended due to them being more of a spot light. The spread and PAR are quite weak. Had I not added the edge bars, I was going to put a third a360x over the 40 to reduce shadows and have better blanket coverage.
Your tank is longer and deeper meaning you will be hard pressed to keep corals at the ends of your tank and close to front/back panels.
In my current tank, my zoas and mushrooms get 225-250 PAR. Acans and favia 150-175. My torches, hammers, frogspawn and gonis average 300. People way under estimate PAR requirements. The vendors/sellers recommends certain PAR, always on the low side, so people hopefully don’t throw a blasto on the highest point in the tank and complain when it fries. I digress. However, you can look at tanks on this site where people with mixed tanks run higher PAR. For example, @JGT has a simply amazing mixed reef and is running some serious lighting. @Troylee grows his torches in 500+ PAR, he even did this under halide before going Meridians.

Rocks reef · 2026-06-19T09:45:33-0400

For reference,

I upgraded to a custom 48x24x20 from Glasscages. I spoke with Liam at ReefBreeders on which size light because the website recommends a Meridian 35 for a 48” tank. However, he said I wouldn’t be able to grow much on the ends of the tank and should go with the 45 inch model. As you can see in the pic, I had to add edge bars to get even coverage on the front and back. My point being is, sure the Meridian 35 may have illuminated the entire sandbed, that doesn’t mean it would sustain corals.

Troylee · 2026-06-19T10:26:46-0400

Rocks reef said:
@A_Blind_Reefer is spot on! You will want the intensity to be pretty maxed out unless you run supplement lighting in front and back.
Even the BRS video stated that over an area 40x20 at 18” depth you will only be averaging less than 100 PAR since the 75g is deeper. Also, those numbers are directly under the light pucks. The outer edges barely saw 70PAR, even less. For example, I had a 40 breeder 36x18x18. I was running two Kessil a360x at 75% just to get 200 on sandbed directly under the lights. The ends of the tank and front/back was probably 100-125. It wasn’t until I added Meridian edge bars front/back that I was able to get an even 200-225 everywhere on the sandbed.
I love Kessil for the color and shimmer, but you need more than what is recommended due to them being more of a spot light. The spread and PAR are quite weak. Had I not added the edge bars, I was going to put a third a360x over the 40 to reduce shadows and have better blanket coverage.
Your tank is longer and deeper meaning you will be hard pressed to keep corals at the ends of your tank and close to front/back panels.
In my current tank, my zoas and mushrooms get 225-250 PAR. Acans and favia 150-175. My torches, hammers, frogspawn and gonis average 300. People way under estimate PAR requirements. The vendors/sellers recommends certain PAR, always on the low side, so people hopefully don’t throw a blasto on the highest point in the tank and complain when it fries. I digress. However, you can look at tanks on this site where people with mixed tanks run higher PAR. For example, @JGT has a simply amazing mixed reef and is running some serious lighting. @Troylee grows his torches in 500+ PAR, he even did this under halide before going Meridians.

My torches still sit in 800 par lol.. under halides and meridians