Water cooling using aquaponics tank

[DrMisunderstood]

At some point i know the small brushless pump for the closed loop will fail and the cobs will fry within minutes,

If you CoBs are drawing 2 Amp or less you could add a TCO thermal fuse for $0.60 using a Panasonic EYP-2BN143.

You could also add redundancy and use two pumps. What you would do is add a water tank higher than the fixture and allow gravity to make the water to flow from the tank through your heatsink to the fish tank. Then you use two pumps to pump the water from the fish tank to the gravity tank.

I built a "Water Tower" out of 4" PVC. While building I found a better was to do it with just the center pillar at a much lower cost. The upper "Water Tank" was not necessary. Gravity does a very good job of keeping the tank empty. This one was about $100 and holds about 3-4 gallons.

 

[ttystikk]

Its rated at 350watts. I'll run the cobs a bit higher and see how much the power supply goes up. Its using about 2/3 rated power. Technically that should be the efficiency sweet spot. But this isnt the first issue i had with it. First the 10k potentiometer broke on it and it was stuck at max voltage, so i stuck a single turn 10k pot in there to get my adjustable voltage back on it. Now its chewing power for no reason. I may just have bad luck with this one.

How hot is it running?

I've had a Meanwell driver fail. They aren't perfect. It is rare...

 

[ttystikk]

If you CoBs are drawing 2 Amp or less you could add a TCO thermal fuse for $0.60 using a Panasonic EYP-2BN143.

You could also add redundancy and use two pumps. What you would do is add a water tank higher than the fixture and allow gravity to make the water to flow from the tank through your heatsink to the fish tank. Then you use two pumps to pump the water from the fish tank to the gravity tank.

I built a "Water Tower" out of 4" PVC. While building I found a better was to do it with just the center pillar at a much lower cost. The upper "Water Tank" was not necessary. Gravity does a very good job of keeping the tank empty. This one was about $100 and holds about 3-4 gallons.

View attachment 3928382

Running the pump constantly is a good way to ensure it keeps running; in my experience they generally fail to start, once they're running they're good for years.

Thermal switch is a great idea and it's cheap. I'm going to look into them.

 

[DrMisunderstood]

Running the pump constantly is a good way to ensure it keeps running; in my experience they generally fail to start, once they're running they're good for years.

Thermal switch is a great idea and it's cheap. I'm going to look into them.

That is true,but it not a matter if it will fail, it's a matter of when it will fail. Reading the review of pumps it appears it is not uncommon for some to die after a month or so. When there is thousands of dollars of LED fixtures an extra $10 pump or two is not a bad investment.

I have the TCO fuses, redundant pumps, and a thermal foldback circuit on each board's LED driver. And I don't think I'm being paranoid. Or am I?

 

[ttystikk]

That is true,but it not a matter if it will fail, it's a matter of when it will fail. Reading the review of pumps it appears it is not uncommon for some to die after a month or so. When there is thousands of dollars of LED fixtures an extra $10 pump or two is not a bad investment.

I have the TCO fuses, redundant pumps, and a thermal foldback circuit on each board's LED driver. And I don't think I'm being paranoid. Or am I?

Noooooo I don't think you're being paranoid. That's why I'm interested in the thermal switches.

 

[Ken Beck]

How hot is it running?

I've had a Meanwell driver fail. They aren't perfect. It is rare...

Ok, now i feel like im going crazy. I hooked up the killawatt to the power supply. Then turned up the voltage to 39.1v. reading showed 380w. Left the power supply plugged in and put multimeter in series in the cob circuit to get the current through the wire which showed 6.6amps, then i look over and suddenly the killawatt shows 288watts?!?! I pull the multimeter out and plug the cob circuit back into the power supply, 380w again? Then i put the multimeter back in again and the killawatt jumps down to 288w...288sounds exactly where the power supply SHOULD be. How could the multimeter affect the reading when it is on the dc side of the circuit? And why cant it read the correct wattage when under load when the multimeter isnt there? I suddenly feel like my knowledge of electronics is very poor lol.

 

[ttystikk]

Ok, now i feel like im going crazy. I hooked up the killawatt to the power supply. Then turned up the voltage to 39.1v. reading showed 380w. Left the power supply plugged in and put multimeter in series in the cob circuit to get the current through the wire which showed 6.6amps, then i look over and suddenly the killawatt shows 288watts?!?! I pull the multimeter out and plug the cob circuit back into the power supply, 380w again? Then i put the multimeter back in again and the killawatt jumps down to 288w...288sounds exactly where the power supply SHOULD be. How could the multimeter affect the reading when it is on the dc side of the circuit? And why cant it read the correct wattage when under load when the multimeter isnt there? I suddenly feel like my knowledge of electronics is very poor lol.

Very weird. I have no idea what's going on!

 

[Ken Beck]

Very weird. I have no idea what's going on!

Ok so i've been reading up on various reasons and i believe that the meter is not accurate because of the changing power factor in the power supply. Apparently the little spikes and differences can throw off its readings and when i put the multimeter in the dc side, it smoothed out the load on the power supply enough for the killawatt to register the correct watt usage. The 288w IS the correct wattage. I can finally put my mind at ease lol.

 

[ttystikk]

Ok so i've been reading up on various reasons and i believe that the meter is not accurate because of the changing power factor in the power supply. Apparently the little spikes and differences can throw off its readings and when i put the multimeter in the dc side, it smoothed out the load on the power supply enough for the killawatt to register the correct watt usage. The 288w IS the correct wattage. I can finally put my mind at ease lol.

Fascinating stuff, I had no idea the power supply could screw with a power meter like that.

288W fits the facts; it's the expected draw and nothing else is getting inordinately hot.

 

[Ken Beck]

It does seem like im not giving updates as often as i should be. But bear with me as i have a lot of projects i've been working on like a chicken coop for the 5 chickens, a dog house with an auto feeder and auto watering system for the now spoiled dogs, the same for the chickens this weekend, then i removed a bunch of mature plants taking up the whole grow bed and put them outside to see how they reacted to the move to soil. Pics of that probably later today. I ran temps with my temp gun to see how the cobs were doing with the new higher voltage of 39.1v and they hold a steady case temp of 86°f. Not bad at all. I may bump the wattage even higher today as well.

 

[Ken Beck]

That is one of the tomato plants we transferred outside. We wanted to try other plants in the grow bed so we pulled 2 tomato plants and a cucumber plant.That is what it looks like now. Left a good chunk of room for the plants to grow.

 

[ttystikk]

View attachment 3930837
That is one of the tomato plants we transferred outside. We wanted to try other plants in the grow bed so we pulled 2 tomato plants and a cucumber plant.View attachment 3930838That is what it looks like now. Left a good chunk of room for the plants to grow.

Nice! Do you measure nitrogen levels in the tank? I'm curious as to whether removing so much plant mass will cause levels to rise, at least until the other plants catch up.

 

[Ken Beck]

Nice! Do you measure nitrogen levels in the tank? I'm curious as to whether removing so much plant mass will cause levels to rise, at least until the other plants catch up.

I have not measured that in awhile actually. I will get that measurement today cause i am curious what it is as well. I gotta grab a gallon of ro water though as i dont want to dilute the sample with tap water.

 

[ttystikk]

I have not measured that in awhile actually. I will get that measurement today cause i am curious what it is as well. I gotta grab a gallon of ro water though as i dont want to dilute the sample with tap water.

And you may have mentioned it before but I was wondering where the nitrifying bacteria live in the system.

 

[Ken Beck]

And you may have mentioned it before but I was wondering where the nitrifying bacteria live in the system.

They remain on the surface area of the clay rocks, most growing mediums used will naturally have the bacteria grow when there is ammonia present. Then as the ammonia converts to nitrite the 2nd set of bacteria grow on the same surface which will finish the cycle converting the nitrite to nitrate. As an added bonus the other nutrients such as phosphorus and potassium those nutrients are already in the fish waste as excess from their food. A fully established bacteria colony should show zero nitrite in the system but you should see a little bit ammonia and a lot of the end result nitrate in there. It really is interesting that you can quantify how much nutrients the fish are putting in, how well the bacteria are converting, and how much the plants are eating.

 

[Ken Beck]

Im not worried about the nitrate levels going up much because i am actually using the fish water to water the plants we have outside and replacing the water in the tank with tap water. It dilutes the nutrients as i keep doing that. And the plants i water with it do very well too.

 

[Ken Beck]

Oh btw, that tomato plant in the picture was started from seed mid January. An heirloom cherry tomato plant. So about 90days from seed to that size.

 

[Ken Beck]

Hmmm nitrate may be higher than i thought... Here is the chart. Nitrate is on the right.Then i did 1/2 dilution

....ok at the end of the chart. Dilute some more.. 1/5 fish water

....now i start worrying lol. Time to test the water im using to dilute it as a control..Crap...test works good nothing in that water...1/10th??...i hope that works because this is getting insane.

Uh oh....

 

[Ken Beck]

Well i can say with certainty that there is over 1600ppm of nitrate in the water. Hold on while i keep diluting down to the point where i am finally in the scale!

 

[Ken Beck]

Finally! 1/20th has me down to 80-160. Its a shade lighter. Im gonna call this done lol.So the one on the left is 1/10th, the one on the right is 1/20th. Its still not accurate at all though as i now have a range of 1600-3200ppm since i know its above 1600ppm but below 3200ppm. Ok i might dilute to 1/50th just to see if i can get more accurate. Wow this water is just crazy full of nutrients. Time to add 2-3 more grow beds and continue watering all plants continually outside.. maybe sell the fish water as organic fertilizer lol. It is super potent with this much nitrate in there.