Dr. Joshi’s 500 Gallon SPS dominated mixed reef

If you are a reef hobbyist, chances are that you are familiar with the legendary Dr. Joshi. Featured by almost, if not every, reef-keeping print...
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    Dr. Joshi’s 500 Gallon SPS dominated mixed reef.

    If you are a reef hobbyist, chances are that you are familiar with the legendary Dr. Joshi. Featured by almost, if not every, reef-keeping print publication, online blog and forum for his coral keeping ability, a quick Google search will reveal his legacy as well as pictures of his beautiful tank.

    Untitled-2.jpg And, my favorite award - MASNA Award for "Outstanding Contribution to the Marine Aquarium Hobby", Marine Aquarium Societies of North America, 2006. -taken from Dr. Joshi’s PSU bio page

    Over the last few months we were able to spend a couple of afternoons with Dr. Joshi and his current reef tank. He graciously let us take yet more pictures of his incredible tank while plying him with questions about the tabling colonies of Acroporas in his care.

    So what got you into the hobby?

    I’ve been in reef-keeping for at least 20+ years, let’s say 25 now. The first reef tank I set up was in ’91. I always kept freshwater fish growing up as a kid, but I was always fascinated by saltwater. When I bought my first house and had the chance to set up a tank I figured I would jump into saltwater. I ended up seeing a reef tank and I said forget the saltwater fish tank, I don’t want just a saltwater fish tank, now what I want is a reef – so that’s what got me into it. There was a local store in town that had a 30-gallon reef tank and I was really impressed that you could do this on such a small scale, so that got me hooked.

    Untitled-1.jpg What keeps you so enthusiastic about being a reef keeper?

    There are so many fascinating things in this hobby for example - in the beginning you just try to keep the easy corals alive, then once you get good at that you start moving on to even harder corals. Starting with soft corals then moving on to stony corals, which was a greater challenge. Once I had a good handle on the corals, the next challenge was fish breeding. That got me into breeding clownfish for a while. There is always something new to get into. Currently I am experimenting with more difficult fish, fish that I had never kept before. But that’s the hobby - there is always something that can keep you interested.

    This tank looks spectacular- you said you have had it for 10 years – is this coral 10 years old?

    No, this tank in its current form is only two and a half years old. I had a major tank collapse while I was at MACNA 2013 in Ft. Lauderdale because of a chiller failure. The temperature in my tank got up to 90 degrees and almost everything died. It was then that I decided to make the switch to EcoTech LEDs so that I could ditch the chiller and not have to worry as much about temperature swings due to my lighting.

    Almost all the coral you seen in this tank has been grown from small frags or small aquacultured colonies.

    Sanjay’s system is largely automated which makes maintenance more manageable.

    Looking at your tank it looks like you have a fair bit going on here. What’s the core system?

    The tank is 7’ x 4’ x 2.5’ glass- ¾ inch thick. As you can see it is built into the wall with a custom cabinet. The filtration and other equipment is in the room behind the tank. I run a sump with additional live rock, Protein Skimmer, and Carbon/Phosphate filtration. The total water volume of the tank plus the sump is probably about 575 Gallons.

    I only dose the basics: Calcium, Magnesium, and Alkalinity. Although when I am asked to evaluate a new dosing product I sometimes add those, but not consistently.

    My targets for Ca, Mg, Alkalinity, and Salinity are all standard hobby levels. The temperature of the tank varies throughout the year. In the winter my tank will run around 74 to 75°, while in the summer it will run around 80°. As for the other parameters, I am currently running a calcium reactor, so I’m concerned about alkalinity. Usually the Alkalinity and Ca numbers are good, so I shoot for a target around 10dkh and I’m happy with up to 12dkh. The Mg doesn’t vary a whole lot and the nitrates typically hover around 10 to 20ppm. Sometimes possibly higher. = I’m ok with that. I don’t really test the phosphates on any regular basis, I assume they are somewhere around .1ppm based on the last test I did a long time ago. I do run a phosphate remover and carbon so I’m just assuming that takes care of it.

    Pretty much everything on the system is automated. I use an Apex controller for my core monitoring and feeding, and EcoSmart Live with a Reeflink for lighting.

    I have a RODI (Reverse Osmosis DeIonization) systems and ATO (Automatic Top Off).


    The fish room contains the plumbing and wiring needed to keep the tank running.

    What do you do for flow and how much is enough?

    Basically I provide as much flow as I am able to without causing coral to lose flesh or become deformed in growth. It is pretty easy to see when coral living close to a return or powerhead is getting a little too much flow as it starts to show deformed growth.

    For equipment I like EcoTech. I run 3 VorTech MP60’s and 1 MP40. I use a combination of EcoSmart and Long Pulse modes and run them at around 60 percent. I have the powerheads positioned so that they are not blasting the coral. I also run night mode so that there is calmer flow at night. In addition I have 2 Maxspect Gyres circulating water across the top of the tank. For returns a Dart Return pump and I have two Vectra M1s for the 2 closed loops.

    If you do the math that’s in the region of 25,000 or more gallons of flow per hour at peak times. That’s over 40x system water volume but this is a heavily dominated SPS tank and especially as it grows in, it is important to keep water movement high for the coral.

    Radion LED Lighting?

    When my tank crashed in 2013 because of the chiller, that’s when I decided to make the change to LEDS. At the time EcoTech had the Gen 2 Pro model so I went with 8 of those. When the wide angle lenses became available I changed my lenses. With the coral grown in I began running out of space and wanted to get more light in the corners, so I recently added two additional G2 PRO units. Eventually, I will be changing the lenses on those to wide angles as well.

    The heat reduction compared to my previous 3 400w Halide setup was significant. Also, the ability to program the fixtures lets me vary the tank lighting throughout the day.

    What does your Radion program look like?

    You can download my program here, but I really only have three settings.

    Full on (all channels at 100%) from 12:00PM to about 7:00PM (7.0 hours)


    My main viewing period during which I reduce the blue to see more natural colors is from 7:00PM to 10:00PM (2.5 hours)

    Followed by a sunset period at 10:00PM-11:00PM (1 hour) during which I run all blue channels to fluoresce the coral.

    That’s a lot of light. Don’t people say that’s too much PAR?

    People have argued about whether or not LEDs will grow coral. I have never had any issue at all – just look at my tank. I ran 1200 watts of halides for 10 hours before and had good growth – now I run roughly the same wattage of LEDs and get better growth on most corals. I’ve had to frag this tank several times in the last two years. I also have great color.

    A lot of people blame lighting when their coral doesn’t grow well or say that red and green light cause algae growth – again I have neither of those issues in my tank so I can only say that some other factor is probably affecting their tank. Each tank is different, however, the trick is finding the perfect balance in your system.

    There are areas of very high PAR in my tank, especially near the surface, and areas where there is shadowing and less PAR. I move coral around sometimes because of lighting or flow and generally put lower light corals where they are shaded

    Some Acroporas seem to like very high light and may be receiving close to 500-600 PAR. Fungia and Zoanthids at the bottom of the tank may be getting around 100 PAR.


    Par readings taken with an Apogee PAR meter. Due to the coral its self – readings were as accurate as possible without causing damage to the coral. Readings are taken at the coral as indicated by the arrows.

    I see a lot of fish. What’s your favorite?

    I would say the current count on fish is somewhere around 45 to 50. I like to keep smaller fish so I can keep more of them. I would say my favorite fish in the tank right now is my Lennardi Wrasse, which I’ve been raising from a juvenile. He is now about 4 to 5” and is just a beautiful fish; it is not a fish you see often kept in captivity.

    I have the standard assortment of tangs and other aquarium fish. I have a number of reclusive blennies and wrasses that I don’t see very often. Every once in a while I will see one come out. That’s one of the benefits to a large tank, you are always finding new things and re-finding fish and coral that you may have forgotten.

    In my opinion a healthy fish population is critical to healthy coral, at least in a well- balanced reef tank.

    And the coral?

    I have mostly Acorapora but there are others, such as, Montiporas, Stylophora, Euphyllia, Fungia and some soft corals like Leathers and Gorgonians. I have some Chalices in there and a whole bunch of different Zoanthids which I keep growing in different corners.

    Like most hobbyists it’s a bit of an obsession, you can never have enough. I don’t have room for it but that won’t stop me.


    One of Sanjay’s Fungia corals has reproduced so prolifically that he has close to a dozen of the same green-turquoise plate thriving around his sand bed.

    Clean-up crew?

    I do not have a large clean-up crew in my tank at the moment; I have a few big Turbo snails, a pair of fire shrimp, a bunch of serpent stars and a bunch of sea cucumbers to help with the sand. I do not think I would be able to accurately guess the quantity right now.


    Dr. Joshi’s foray into clownfish breeding can be seen in a series of small tanks located in his sump. Many of the mating pairs are tending to their eggs.

    What do you feed?

    I generally feed the fish a mix of different kinds of frozen foods like PE Mysys and Hakari Mysis to name a few and some pellet food. I don’t feed the corals directly, however, once in a while I will get samples from people to try and I will use those, but I generally don’t see any major difference so I don’t have any sort of coral feeding regiment. It mostly seems that the corals are feeding off of fish poop, detritus and any other bacterial stuff they can find.


    Ending Observations and Advice?

    The industry has changed a lot over the past ten years, definitely for the better. The technology that is available to help people keep reefs successfully, such as, better pumps, better lights and just better equipment overall, is remarkable. The selection of corals has broadened as well; there are a lot of different corals now coming in from parts of the world that not too long ago were not accessible to your average hobbyist. There is also a lot more knowledge available than there was ten years ago; people have become better at keeping these ecosystems happy.


    Dr. Joshi shares his love of reef keeping with 12 year old Sammy – his energetic Poodle Spitz mix.

    Also, the techniques have changed in the sense that there have been newer techniques that have come into play that didn’t exist when I first started doing things. A lot of things like carbon dosing, for example, have come around; people are using bio pellets and experimenting with different technologies. In the end they all kind of shoot for the same goal, maintaining the water quality. Interestingly, if you understand the chemistry and biology of things, you can pretty much run your tank on what we knew 15-20 years ago, but you’d be more successful doing it now with the technology and resources available. We now have a much better understanding of the chemistry, biology, and inner workings of these things, but there is still a lot we do not know.

    Learn as much as you can about what you are going to keep – that I think is the key to the whole thing, all of the chemistry, biology, habits and tendencies of the animals that you keep and everything else.




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