No Growth From Gigas.

[jda]

How is the phosphate level? Phosphates inhibit calcification.

The coralline growth looks good, but is that legacy, or do you scrape the glass of new coralline "spots" often? If coralline is not popping up everywhere, then calcification could be inhibited a bit.

 

[Dana Riddle]

My 2 cents worth. I ran some tests on rates of photosynthesis with a PAM fluorometer on a T. crocea a few years ago, and there was no sign of photo-saturation at a PAR of 600. A few years later, I found a Master's thesis on the web, and that fellow found no photosaturation at very high PAR (>1,500.) In other words, it is doubtful that a large clam can be over-illuminated in an aquarium. I looked in my zooxanthella clade database and found that 4 of 5 T. gigas tested contained Clade 'A' - which are known to be tolerant of very high light intensity. On top of this, the mantle of a clam gets thicker as the clam grows and zoox can begin to shelf-shade from light. Finally, the coloration reflects blue - certainly within the range of being photosynthetically important. I've had a couple of clams over the years that died suddenly, and I've suspected light starvation was the cause.

 

[jda]

Don't forget that T clams can digest extra zoox for more energy. I would be surprised if we can over light them.

 

[Troy V]

My only outlandish thought would be a lack of a specific NM that effects growth(the MHs alone should cover that though) , or conversely too much of one or several that that’s causing photoinhibition. Stunting growth.
With clams I didn’t think that truly possible. Those par numbers and spectrum “should” be fine.
Odd. And interesting.

How long is the peak photoperiod?

Maybe we could ask @Dana Riddle what he knows about clams.

The 250 MH comes on from 2 to 6 and the Hydra 52s start at 7:50 and ramp up to peak at 2:10pm UV 68%, Violet 65%, Royal Blue 124%, Blue 95%, Green 54%, Red 25%, and Cool White 35% the light are out at 8:30, then moon light. I tried taking a screen shot of my setting but I could get the image to load.

 

[Troy V]

My 2 cents worth. I ran some tests on rates of photosynthesis with a PAM fluorometer on a T. crocea a few years ago, and there was no sign of photo-saturation at a PAR of 600. A few years later, I found a Master's thesis on the web, and that fellow found no photosaturation at very high PAR (>1,500.) In other words, it is doubtful that a large clam can be over-illuminated in an aquarium. I looked in my zooxanthella clade database and found that 4 of 5 T. gigas tested contained Clade 'A' - which are known to be tolerant of very high light intensity. On top of this, the mantle of a clam gets thicker as the clam grows and zoox can begin to shelf-shade from light. Finally, the coloration reflects blue - certainly within the range of being photosynthetically important. I've had a couple of clams over the years that died suddenly, and I've suspected light starvation was the cause.

Thank you for your response Dana.

 

[jda]

If you are worried about light, run the Halide more and put a 6500K or 10K bulb in there. These are shallower water clams and might really love the output of a 6500 or 10K.

 

[Troy V]

How is the phosphate level? Phosphates inhibit calcification.

The coralline growth looks good, but is that legacy, or do you scrape the glass of new coralline "spots" often? If coralline is not popping up everywhere, then calcification could be inhibited a bit.

That is legacy coralline growth, and the PO4 has gone from .05 to .02 since I started dosing KNO3 last Tuesday. Before I started dosing KNO3 I would use GFO when the PO4 levels would hit .06ish. There is a definite calcification difference when my PO4 levels are .04>.

 

[Troy V]

If you are worried about light, run the Halide more and put a 6500K or 10K bulb in there. These are shallower water clams and might really love the output of a 6500 or 10K.

Since I added the MH I believe I have adequate lighting to sustain it. But I find it interesting how the growth patter has altered so much. I tried calling the Waikiki Aquarium several times to see if they had a similar issue when they moved their Gigas. They never got back with me, I then read that they lost 2 of their old Gigas clams. It seem to be a bit of a sore issue for them. Also the rate of consumption of NO3 that seems to be quite substantial. It seems I can barley get my levels to .02 ppm. I wonder if this also lead to there demise. Especially since they had several large specimens.

 

[Troy V]

Here is the article I found about the Waikiki Aquarium.
https://reefbuilders.com/2015/05/06/waikiki-aquarium-management-head-sand-animal-deaths/

 

[jda]

Most of the NO3 that gets added fuels a increase in anoxic bacteria in the rock and sand. This is why it disappears so fast. You have to keep adding and adding or else else it will get back down to near-zero again. I do not think that near-zero is an issue as long as it is naturally done - carbon dosing to low levels can be dangerous since they go too far.

In any case, the clam should be able to get all of the nutrients from the light if you do have enough.

 

[Troy V]

Most of the NO3 that gets added fuels a increase in anoxic bacteria in the rock and sand. This is why it disappears so fast. You have to keep adding and adding or else else it will get back down to near-zero again. I do not think that near-zero is an issue as long as it is naturally done - carbon dosing to low levels can be dangerous since they go too far.

In any case, the clam should be able to get all of the nutrients from the light if you do have enough.

Interesting.. The clam might be alright but do you think a clam can remove NO3 to the detriment of other animals? Especially one that weighs over 100lbs? I do not run a deep sand in fact in both side tanks it is 1/2" or less, and the center tank is around 1" with a Dragon goby to keep it aerobic. Also I am a minimalist when it comes to live rock. Most of what you see is a PVC platform with rock on it. I make it a practice to keep the live rock off the sand bed to help eliminate anoxic zones. You are right about the denitrification that a DSB can provide. Many years ago I had success when I ran a remote DSB in a 5 gallon bucket. My system is large and I have a decent size bio load with 30 fish that are fed daily. Plus I am added 2 gallons of freshwater with a concentration of 50ppm of NO3 a day, and I am barley registering a change at .02. Curious?? Also since I've been dosing the coral are showing a marked improvement.

 

[rockskimmerflow]

Interesting.. The clam might be alright but do you think a clam can remove NO3 to the detriment of other animals? Especially one that weighs over 100lbs? I do not run a deep sand in fact in both side tanks it is 1/2" or less, and the center tank is around 1" with a Dragon goby to keep it aerobic. Also I am a minimalist when it comes to live rock. Most of what you see is a PVC platform with rock on it. I make it a practice to keep the live rock off the sand bed to help eliminate anoxic zones. You are right about the denitrification that a DSB can provide. Many years ago I had success when I ran a remote DSB in a 5 gallon bucket. My system is large and I have a decent size bio load with 30 fish that are fed daily. Plus I am added 2 gallons of freshwater with a concentration of 50ppm of NO3 a day, and I am barley registering a change at .02. Curious?? Also since I've been dosing the coral are showing a marked improvement.

I'm not sure why you think adding 2 gallons of 5oppm concentration nitrate water to a 500+ gallon system is a lot. You're really not adding much at all to the grand scheme of things if I'm understanding the specs of your system and the nitrate concentration you spec at 50 being the ppm of your top off water not the overall additive effect to the system. I have systems with no clam life that consume a lot more nitrate daily than what we're looking at here. I think you'd be safe to add more nitrate or increase feeding - so long as you keep an eye on your phosphate and bias your nutrient input towards feeding if your phosphates fall and nitrates if you notice them climbing. I doubt you're even scratching the surface of what a system with a clam that size can pull in terms of daily nitrate uptake. Also more light would certainly not hurt if you're trying to get the clam to grow. I always err on the side of more light with clams since bleaching one is probably way more difficult than starving it of light is. Very cool systems btw, wicked gigas clam for sure. Best of luck with him and hopefully a long future.

 

[Troy V]

Thank you for the response. Those are some good points you make. Are you adding NO3? Other than feedings? If so what concentrations? I was hoping to see at least 1ppm registering on a test kit. I just checked it again and I can't see a color change. But like what JDA said it could be getting absorbed/consumed elsewhere. I wanted to take it slow but I think I will double the dosage next week. 100ppm concentration and see where that takes me. As for lighting I will increase the photo period on the Hydras' and see where that takes me. The real kicker is that when I moved the clam to the temporary holding tank before I moved it to its current tank it was growing amazingly fast.

Look at the new growth on it, and that was under 4 t-5s. This is also after it spawned every day for a couple of weeks. Totally stressed out from the move. I think the last move to its current tank really hurt him.

 

[rockskimmerflow]

Thank you for the response. Those are some good points you make. Are you adding NO3? Other than feedings? If so what concentrations? I was hoping to see at least 1ppm registering on a test kit. I just checked it again and I can't see a color change. But like what JDA said it could be getting absorbed/consumed elsewhere. I wanted to take it slow but I think I will double the dosage next week. 100ppm concentration and see where that takes me. As for lighting I will increase the photo period on the Hydras' and see where that takes me. The real kicker is that when I moved the clam to the temporary holding tank before I moved it to its current tank it was growing amazingly fast.

Look at the new growth on it, and that was under 4 t-5s. This is also after it spawned every day for a couple of weeks. Totally stressed out from the move. I think the last move to its current tank really hurt him.

I hear you on those points. I do dose nitrate but I manage too many customer tanks that all take various dosages to maintain my target level of roughly 1-4ppm to give any blanket answer of concentration or dosage volume. Each tank will have its own specific needs that must be tested for and adjusted accordingly as those needs change over time due to the growth or livestock or other manipulations to the general operation of the aquarium. For your tank I just don't think you're putting in enough nitrate yet to even register on the test, and I will explain why more fully below.

Now, correct me if my math is wrong guys, but for simplicity's sake lets say you have 500g sitting at basically zero nitrate and you add 2 gallons at 50ppm - according to my numbers you'd have only added 0.2 ppm of nitrate that day. IME it's very, very easy for a tank to suck 0.2ppm out of solution in a day's time. I usually find SPS systems capable of pulling out 1-3ppm daily without breaking a sweat. I'm sure there are guys out there who have tanks full of colonies with high irradiance levels that pull quite a bit more than that. Especially tanks running large chaetomorpha or other algal refugiums.

There will necessarily be biological/bacterial action that is accounting for some of the daily consumption of nitrate in your system. But when we're talking about 0.2ppm being added it's really hard to say what exactly is accounting for the bulk of the uptake. I'd try adding more if you're so inclined and see what the results are. Slow and steady is best of course, but I don't think you'll do any harm by increasing the dosage a bit. You'd need 2 gals of stock 200 ppm solution added daily to increase your 500g system by 0.8ppm each day. That might be a short term target number to try out. Best of luck with the tank. It's always fun playing with new tweaks and optimizations.

Also, that growth under the 4 bulb T5 unit looks phenomenal. T5HO's are absolutely no joke but it seems people have it in their mind that a pair of LED pendants run at similar peak wattage are somehow much more effective at growing stuff than an old school 4 banger T5HO, but I would take that 4 bulb any day over a pair of hydras personally.

 

[Nart]

Thank you!
It really depends on the system, and how your coral looks. For me my SPS started to turn pale and lacked any color contrast. But if you have color and everything else is doing well I really wouldn't worry about it. Especially since it is difficult to predict the correct amount of NO3 for your system. Too much can have a very negative effect. I would say that the phyto feast you are dosing would supply an ample amount of nitrogen to feed the system.

Yes you are correct I am dosing 2 gallons of RODI water that has a 50ppm of NO3 each day. Yesterday I dosed an additional 2 gallons of water on top of the ATO 2 gallons and still no noticeable change. Frustrating!

Thank you for the response Troy.
Now I am wanting to just plan my tank around a clam too

 

[jda]

This is going to be contrary to all that you hear, but I would not run the Hydras over such a fine animal. The cut spectrum and too-high of peaks in some of the diodes might be fine for some softies and run-of-the-mill stuff, but for me, that beauty deserves only the best light that it can get. The output from a Hydra and a Halide are not even close to the same. I would just run the halide on it 10 hours a day.

I do not have a Gigas, but my Squamosas are 11 and 9 inches of shell now on .1N and .01P. These levels are not nutrient limiting and close to natural seawaer. They do get lots of halide light all day.

I will need to open some of my books, but I cannot remember if clams need more energy as they grow - I know that they get bigger, but I cannot remember if they need even more than the new growth can capture.

 

[Troy V]

I hear you on those points. I do dose nitrate but I manage too many customer tanks that all take various dosages to maintain my target level of roughly 1-4ppm to give any blanket answer of concentration or dosage volume. Each tank will have its own specific needs that must be tested for and adjusted accordingly as those needs change over time due to the growth or livestock or other manipulations to the general operation of the aquarium. For your tank I just don't think you're putting in enough nitrate yet to even register on the test, and I will explain why more fully below.

Now, correct me if my math is wrong guys, but for simplicity's sake lets say you have 500g sitting at basically zero nitrate and you add 2 gallons at 50ppm - according to my numbers you'd have only added 0.2 ppm of nitrate that day. IME it's very, very easy for a tank to suck 0.2ppm out of solution in a day's time. I usually find SPS systems capable of pulling out 1-3ppm daily without breaking a sweat. I'm sure there are guys out there who have tanks full of colonies with high irradiance levels that pull quite a bit more than that. Especially tanks running large chaetomorpha or other algal refugiums.

There will necessarily be biological/bacterial action that is accounting for some of the daily consumption of nitrate in your system. But when we're talking about 0.2ppm being added it's really hard to say what exactly is accounting for the bulk of the uptake. I'd try adding more if you're so inclined and see what the results are. Slow and steady is best of course, but I don't think you'll do any harm by increasing the dosage a bit. You'd need 2 gals of stock 200 ppm solution added daily to increase your 500g system by 0.8ppm each day. That might be a short term target number to try out. Best of luck with the tank. It's always fun playing with new tweaks and optimizations.

Also, that growth under the 4 bulb T5 unit looks phenomenal. T5HO's are absolutely no joke but it seems people have it in their mind that a pair of LED pendants run at similar peak wattage are somehow much more effective at growing stuff than an old school 4 banger T5HO, but I would take that 4 bulb any day over a pair of hydras personally.

You are correct with your math. I was trying to take it very slow and hope that the NO3 levels would progressively build from a surplus. But as you stated I was way off on calculating aquarium consumption. I will quadruple the stock mixture and see where it goes. I would like to see the 1-4ppm mark in the next few weeks. You are right about T5s being powerful. They can be very deceiving because they lack the intense shimmer the MH give off in comparison. However because of the tank dimensions the par numbers in that tank were far from ideal it was only around 90 at the top of the clam. But it definitely loved the quality of the spectrum it was receiving.

 

[User1]

Well...there goes any thought of me ever keeping a clam. For some reason I didn't think they grew that large him home aquaria. I was wrong.

Question. Your choices are to upgrade and sell I guess. What is the survival rate when you move something that large? And can you even? And how? I know, lots of questions - ignorance is bliss I guess. Really - I was planning on getting one at some point but I would have to say it is now off my list.

Really nice though - you should be proud!

Edit: It just dawned on me - what happens if you can't fit it out of the aquarium say if it is EURO braced (mine is).

 

[Troy V]

Edit: It just dawned on me - what happens if you can't fit it out of the aquarium say if it is EURO braced (mine is)

That is the issue I had with my last tank. It had 2-20" center braces which left me 3- 20" openings between center braces to access the tank. When we removed the clam it had to be put up on it's side to fit through the opening. That is why I had to upgrade tanks, so I wouldn't need to dismantle the aquarium to get to it.

Here is a video of us removing it using manpower and an automotive cargo net.

And this when we put it into the current system.

 

[Troy V]

Well...there goes any thought of me ever keeping a clam. For some reason I didn't think they grew that large him home aquaria. I was wrong.

Question. Your choices are to upgrade and sell I guess. What is the survival rate when you move something that large? And can you even? And how? I know, lots of questions - ignorance is bliss I guess. Really - I was planning on getting one at some point but I would have to say it is now off my list

A few days from now will mark the 10th year that I've had it. It's been a lot of fun, but I would never own another clam this size. Before, when the Gigas was much smaller. I had a 9" Teardrop Maxima, 16" Squamosa, and a 12" Derasa all I grew from around 2"-3". They all (except the Derasa) seemed to reach a max size, and then stop growing for me. They add such a unique dimension to a reef. Please don't let the extreme stop you. They are incredibly rewarding creatures to own. IMO they are the perfect specimen to own. They are like large photovoltaic cells that filter water. Just get a species that fits your tank.