Why is my tank getting hot?

[BeanAnimal]

Try a DC return pump

A watt is a watt… watts don‘t care about ac or dc.

 

[Ef4life]

Any direct natural sun light hitting the tank? How about the wall it’s next too? Is it getting hot with afternoon sun and in turn heating up from the residual heat going through the wall. I live in the desert and I can feel the summer suns heat through 8” of concrete block, 2” of insulation and 1/2” of Sheetrock during the summer inside my house when the wall is getting direct sunlight in the afternoon.

The other thing I was going to say is 81* is really not an issue, it’s on the higher side of what most reefers consider normal 78-79ish but if it says consistent at 81 or lower your tank will be fine. But having a fan and a simple ink bird or some kind of controller is a good idea to keep it from overheating

 

[a.t.t.r]

Wait is this true? A 50w heater I assume is converting all of that energy to heat whereas I assume an efficient pump is using most of that energy to do work in moving water against gravity.

yes. Unless the energy leaves the tank a watt is a watt is 3.41 BTU. so the only energy leaving the tank from a pump would be vibrations, sounds, any ripples on the surface interacting with the air. So for simplicity sake yes, same as a heater.


If you put a 10 watt heater and a 10 watt fan in a perfectly insulated set of boxes the temperatures will rise at the exact same rate.

I struggle with heat in my 20 gallon as well. External pumps can help a little but are hard to do on a small tank and things like the vortech are overkill.

 

[a.t.t.r]

50W, but it's definitely not on during this period (you can see it's on before the temp spikes at 1pm each day.

lower your temp on the heater so you start lower each day as well. 74 is fine. Temp stability is overrated

 

[Court_Appointed_Hypeman]

If your house is at 77 then its reasonable to expect +2 degrees from a pump and powerhead in such a small volume.

If my house gets to 77 my tank will be at 79.5 at least.

You might just need to clean your pump if this is a recent phenomenon. Is your home usually reaching 77 prior to this?

Could also be your probe, I would verify it.

 

[Areseebee]

A watt is a watt…yes some of the energy is converted to noise and water flow, but a relatively small amount and the water flow dissipates most of its emergy into the tank anyway amd too is heat…

So yes, a submerged 50W pump puts roughly the same energy into the water as a heater.

Yeah so I was trying to figure out if this is true. Like even ignoring the fact that yes a pump is not 100% efficient at converting electricity to work on the water, I was trying to figure out why lifting water a few feet will eventually produce heat. I think the thing I was forgetting is if this is a closed system the water has to come back down and so that energy will be converted to heat and noise in the system. So now I do see.

 

[Areseebee]

Any direct natural sun light hitting the tank? How about the wall it’s next too? Is it getting hot with afternoon sun and in turn heating up from the residual heat going through the wall. I live in the desert and I can feel the summer suns heat through 8” of concrete block, 2” of insulation and 1/2” of Sheetrock during the summer inside my house when the wall is getting direct sunlight in the afternoon.

The other thing I was going to say is 81* is really not an issue, it’s on the higher side of what most reefers consider normal 78-79ish but if it says consistent at 81 or lower your tank will be fine. But having a fan and a simple ink bird or some kind of controller is a good idea to keep it from overheating

I think the windows are pretty well covered... It's probably 3 feet from a window. It IS right next to the wall heater board (forced air) but I don't believe our heater is on yet. There also is a sky light but I think that's closed too, I'll double check. The wall itself is shared with a typically cold part of the house.

I agree that 81 should be ok though I did worry at least a little about the swing. The main problem is that because of the temperature my lights had to be off more or less all day and it's only October.

I think overall, the lesson I'm taking from this is that I will struggle with heat because it's only 10g and between a powerhead, lights for SPS and a return that's already quite a bit of heat getting dumped into the tank. I ordered a DC pump, hoping that I can run it at lower wattage to move the same water.... not sure if that's true but it probably can't hurt that it's newer. I suspect I will have to turn down my lights some. I downloaded one of these PAR cell phone apps yesterday and I suspect I have too much PAR anyways.... this doesn't help much since even when the lights are off it doesn't cooldown.

Overall I think the thing that confuses me is that this is a relatively new problem. You can see from that plot I show that up until like Oct 1st, the heater cycled on and off continuously. The tank hasn't been up for long, and it's hard to pinpoint because changes are kind of constant at this stage (like the powerhead is only a few weeks old for instance).

 

[Reefer Reboot]

So what can we derive from the data evidence from your graphs? Your pumps are running 24/7 but the temperature still varies. Looking at the graph, what else varies in sync with the temperature? The lights. Also on the extended graph it looks like the temperature was steady until Oct 1st. So what changed. Were the lights running and at the same position before Oct 1st? Did the temperature probe get moved? Is the temperature probe fully submerged? Has the temperature probe been calibrated recently? Can you show a graph with temp and lights from a few days before until now? It would be helpful to see for comparison purposes.

 

[Areseebee]

Ok all good questions. I agree, what changed Oct 1st is what I've been trying to ask myself. I actually assumed there were some equipment changes around then but there wasn't. I did start running my lights more full time, but you can see when I was/wasn't by fusion.

The temperature probe is fully submerged. I think it is running hot, I tried to check it using a meat thermometer that I could calibrate (in an ice bath). I was a little sheepish about sticking the metal prong into the tank because I didn't really know what it was made of.

I'm actually not sure how to calibrate the apex temp probe because I don't have any measurement device that I believe to be "true". I did order 2 of these little black battery powered thermometers that are like 5 bucks on amazon. The little black thermometer is ~1 degree cooler than the apex reading at all times (similar location in the return chamber). The temp reading on my hannah salinity is also systematically lower but nothing crazy. I did switch it over to my PM2 module at some point to try to correct salinity measurements which actually bumped the reading up systematically as well. Overall I'd say that I'm less concerned with the specific number and more so about the trend. Though maybe I should worry more about getting that right because if the tank is actually 78 and the house is 77 it makes sense that any small amount of heat is causing the temp to rise a lot and I shouldn't worry.

All this is to say: what's the best way to calibrate a temp probe?

 

[Lbrdsoxfan]

Could also be your lighting is causing your heat issues. Does your peak lighting start @ 1 p.m.

 

[BeanAnimal]

yes. Unless the energy leaves the tank a watt is a watt is 3.41 BTU. so the only energy leaving the tank from a pump would be vibrations, sounds, any ripples on the surface interacting with the air. So for simplicity sake yes, same as a heater.


If you put a 10 watt heater and a 10 watt fan in a perfectly insulated set of boxes the temperatures will rise at the exact same rate.

I struggle with heat in my 20 gallon as well. External pumps can help a little but are hard to do on a small tank and things like the vortech are overkill.

Sounds like you have been reading my posts for the past 15 years

 

[laconic]

I got this from Etsy. I dont see it on the sellers store but its great. I would reach out to him. It uses a 24v port on the APex 832

 

[BeanAnimal]

Yeah so I was trying to figure out if this is true. Like even ignoring the fact that yes a pump is not 100% efficient at converting electricity to work on the water, I was trying to figure out why lifting water a few feet will eventually produce heat. I think the thing I was forgetting is if this is a closed system the water has to come back down and so that energy will be converted to heat and noise in the system. So now I do see.

You just basically acknowledged The First Law of Thermodynamics - AKA The Law of Conservation of Energy

BTW - if the water does not "come back down" we can pretty easily figure out how much energy it has stored based on the lift height and its mass

 

[Reefer Reboot]

Ok all good questions. I agree, what changed Oct 1st is what I've been trying to ask myself. I actually assumed there were some equipment changes around then but there wasn't. I did start running my lights more full time, but you can see when I was/wasn't by fusion.

The temperature probe is fully submerged. I think it is running hot, I tried to check it using a meat thermometer that I could calibrate (in an ice bath). I was a little sheepish about sticking the metal prong into the tank because I didn't really know what it was made of.

I'm actually not sure how to calibrate the apex temp probe because I don't have any measurement device that I believe to be "true". I did order 2 of these little black battery powered thermometers that are like 5 bucks on amazon. The little black thermometer is ~1 degree cooler than the apex reading at all times (similar location in the return chamber). The temp reading on my hannah salinity is also systematically lower but nothing crazy. I did switch it over to my PM2 module at some point to try to correct salinity measurements which actually bumped the reading up systematically as well. Overall I'd say that I'm less concerned with the specific number and more so about the trend. Though maybe I should worry more about getting that right because if the tank is actually 78 and the house is 77 it makes sense that any small amount of heat is causing the temp to rise a lot and I shouldn't worry.

All this is to say: what's the best way to calibrate a temp probe?

I wouldn't worry too much about having an exact temperature reading. I have a few of those cheapy thermometers also. I just took an average of all the readings and adjusted the apex to that. Close enough. Can you try putting the probe somewhere besides the return chamber? preferably in the DT or at least in the first chamber of the sump/AIO. This would give a more accurate idea of what the critters are experiencing. As others have mentioned, having a fan blow some air between the top of the water surface and the bottom of the lights will help with the fluctuation. When did you start running your lights "more full time"?

 

[Areseebee]

You just basically acknowledged The First Law of Thermodynamics - AKA The Law of Conservation of Energy

BTW - if the water does not "come back down" we can pretty easily figure out how much energy it has stored based on the lift height and its mass

Yeah agreed, the first law was why I was thinking that it was ok (I can use energy to do work). I just hadn't defined my system very well... it wasn't closed. I have to convert that stored energy back at some point.

 

[vetteguy53081]

Temperature from lights are my culprit but I run a chiller unit to compensate.

 

[Alan Z.]

Does you tank sit near a window? Afternoon sun will heat the water up.

 

[Areseebee]

Ok, so I sat down and calibrated my temperature probes. I care about this not because I want to peg my temperature at a specific number, but rather that if I'm thinking my tank is at 80 and the room is at 77, it should be possible to manage heat. However if the tank is ACTUALLY at 77 and I'm trying to decrease the temp but the room is at 77, that's impossible. If I'm trying to dissipate heat into the ambient, the difference in temperatures between the two matters a lot. So anyways, this had me bring the probe down roughly 2 degrees. I think this will make a big difference actually.

So far today it's "ok"... the temperature is still cycling up and down and it's 2pm. I did also decrease light intensity quite a bit. I downloaded a phone PAR meter called Photone which had a good review on some website but no clue how good it actually is. Regardless, I think I was getting too much light, it was measuring ~500 PAR at the surface. As a result I turned the light down about 20% so it's more like 400 or so at the surface right now. I haven't added back in my powerhead yet, I also ordered a DC pump which is newer so hopefully more efficient but also such that I can dial it down if I need to.

 

[Jason_MrFrags]

turn your heater down 77-77.9 is fine

 

[Areseebee]

turn your heater down 77-77.9 is fine

Ok it was 78-79 at one point, maybe that was just the number in my head from before. I turned it back down to 77.5-78.5 for now. Maybe I'll inch it down again next week.