abcha0s' 300G Ultimate Reef

[abcha0s]

Whenever you think of heat in a reef tank, you immediately think of chillers and evaporative cooling. Well, at least that's the first thing that came to my mind. Heating a tank is just an after thought for the occasional cold night.

I am having a real problem with heating my tank. Without the lights on, the ambient water temperature is around 65F. That's with all of the pumps and power heads running. That's not even close to 78F.

I'm going to be lighting this tank with LEDs. There's very little radiant heat from these lights.

I've done tons of research on LED lighting and everyone points out that without MH lighting, you don't need a chiller. This equates to cost savings in both capital and operational expenses. Well, not if you consume huge amounts energy heating the tank?

I have 4 Marineland Visitherm 300W heaters hooked up right now and the tank is really struggling to approach 78F. That's 1200W of heating! Do I need more?

I'm well aware of the problems with heaters including stuck on, stuck off, exploding, etc. I have the 4 heaters connected to my Apex. In the future I may split this load across 2 Apex controllers (2 on each). I'm reasonably confident in this approach and should be able to catch a disaster before it happens.

I've also noted that the sump temp is generally cooler than the display tank. I haven't yet measured the exact variation, but it seems consistent.

I'm currently heating the return section of the sump and measuring the temp in the chamber right before the return section. Therefore, heated water has to circulate through the tank and back to the sump before the temperature sensor is able to detect a change. This seemed like a good idea as it ensure that the heated water fully mixes before the temperature measurement is taken, but I am less sure of this now.



I'm also considering insulating the sump, but I'm really not sure how much that would help?

Does anyone have any experience or advice in keeping tanks warm? - Is there a better approach to this? - Are titanium heaters really more efficient (I've heard of higher than average failure rates, but possibly better performance)?

I appreciate the feedback...

- Brad

[phi delt reefer]

have verified that all four heaters work? I would put each one in a 5 gallon bucket of water and test them

also the apex and other controllers sometimes have outlets that only work for certain things (relayed outlets or something) You may want to make sure the apex is actually able to power the heater on each of the outlets you're using.

[Lampshade]

You can't count 100% of heater use as a "loss" technically, any "lost" heat is going into your house, which you are also paying to heat. The only lost heat would be days that your house is hotter than your tank. It is inefficient heating, but unless you have a nice heat pump(by the look of your HRV you might) it isn't too bad.

Not to mention the 9 month of calgary winter....

Nice build though, I've been watching for awhile, looks great and good detail.

[Delphinus]

How much turnover do you have in your sump compared to tank volume? I've always heard the general rule of thumb that you need around 5 to 7 times volume turnover through the sump to keep heaters down there. I'm sure you have this or knew it already but it bears asking.

What's the ambient temperature in your house? All things being equal your tank should equalize to that after some time and you would only need to heat your tank the incremental difference. Ie., house at 21c the heaters need only raise it 5c to get to 26c (sorry I don't think in terms of F for temperature. The very first dive I ever did was at the Great Barrier Reef, the water temp there was 26c, and that's what stuck in my head mentally ever since). If you run your house at say a chillier 18c the heaters need only bump it 8c to get to 26c. That's not a lot.

So I'm thinking that either the heaters aren't outputting what you think, or there is loss of heat to somewhere (the floor? is the sump sitting directly on concrete or is there foam under the glass?)

If all 4 heaters were on that should be the full 1200w which seems ample to me. By contrast, my 280g, I use one 1000W titanium heater on a Ranco controller, the RO/DI was a frigid 8c filling up, and the heater brought it to 26c within 24 hours (not sure exactly how many hours it took, I just checked the next day and it was 26c). It's been steady ever since. So I think your 1200W should be doing the trick, there is something more going on here that we haven't put our finger on methinks.

[hillegom]

I just read this entire thread. Great build and well thought out.

[abcha0s]

Originally Posted by Delphinus

How much turnover do you have in your sump compared to tank volume? I've always heard the general rule of thumb that you need around 5 to 7 times volume turnover through the sump to keep heaters down there. I'm sure you have this or knew it already but it bears asking.

What's the ambient temperature in your house? All things being equal your tank should equalize to that after some time and you would only need to heat your tank the incremental difference. Ie., house at 21c the heaters need only raise it 5c to get to 26c (sorry I don't think in terms of F for temperature. The very first dive I ever did was at the Great Barrier Reef, the water temp there was 26c, and that's what stuck in my head mentally ever since). If you run your house at say a chillier 18c the heaters need only bump it 8c to get to 26c. That's not a lot.

So I'm thinking that either the heaters aren't outputting what you think, or there is loss of heat to somewhere (the floor? is the sump sitting directly on concrete or is there foam under the glass?)

If all 4 heaters were on that should be the full 1200w which seems ample to me. By contrast, my 280g, I use one 1000W titanium heater on a Ranco controller, the RO/DI was a frigid 8c filling up, and the heater brought it to 26c within 24 hours (not sure exactly how many hours it took, I just checked the next day and it was 26c). It's been steady ever since. So I think your 1200W should be doing the trick, there is something more going on here that we haven't put our finger on methinks.

Thanks for the feedback Tony

I have almost exactly 4X turnover through the sump (300G total water volume - 1200Gph measured return). I had never heard the 5-7X guideline before, but it is interesting though. I'm sure it has to do with the rate of mixing and the temperature variance between the display and the sump. More turnover would reduce this variance, but heating the water in the sump to a higher temp should also counter this effect.

Ambient house temp is ~20C. 78F converts to 25.6C, so our targets are similar enough. The heaters have to provide ~6C of additional heat.

We have our furnace thermostat set to lower the temp during the day while we are at work and at night while we are sleeping. I think I will have to consider the effectiveness of this strategy.

I'm interested in the titanium heaters. I've read that they are more efficient watt for watt than traditional glass heaters. By the sounds of it, they may be considerably more efficient. I'm not getting anywhere near that much heating power from my heaters. They aren't exactly expensive either, so I will probably cut my losses and go in that direction.

As you suggested, it's likely a combination of factors. I'm still working out the bugs but I'm getting really close to adding the first fish!

[abcha0s]

Originally Posted by hillegom

I just read this entire thread. Great build and well thought out.

Originally Posted by globaldesigns

Very impressive build and I must say one of the best organized build threads out there.

It is like you write manuals/books for a living, well done.

Thanks guys. I really appreciate the encouragement. It keeps me motivated.

[abcha0s]

Originally Posted by Lampshade

You can't count 100% of heater use as a "loss" technically, any "lost" heat is going into your house, which you are also paying to heat. The only lost heat would be days that your house is hotter than your tank. It is inefficient heating, but unless you have a nice heat pump(by the look of your HRV you might) it isn't too bad.

Not to mention the 9 month of calgary winter....

Nice build though, I've been watching for awhile, looks great and good detail.

Hey Lampshade

I've seen this effect first hand. The first winter that my 90G tank was running, our gas usage was roughly half of what it had been the previous year. That's with the MH lighting, but the point is the same. The heat from the tank, does heat the house.

Unfortunately, a heat pump might have to wait 10 or 20 years

[abcha0s]

Originally Posted by phi delt reefer

have verified that all four heaters work? I would put each one in a 5 gallon bucket of water and test them

also the apex and other controllers sometimes have outlets that only work for certain things (relayed outlets or something) You may want to make sure the apex is actually able to power the heater on each of the outlets you're using.

Hey Phi Delt

I haven't done the bucket test, but your right to an extent. One of the things that seems to be happening is that the heaters are turning on and off. I think this is in part due to their close proximity to each other. I have their thermostat set at 81F (or close) and the Apex set at 78F, but even at 81F they are cycling. I think the radiant heat from the neighboring heaters is causing this. I thought that the water turbulence would be sufficient in the small sump chamber to avoid this, but perhaps not. I will move them further apart or set their thermostats higher.

The Apex Energy Bar 8 (EB8) is rated at:

8 independently controllable 120V Outlets (Max 5 Amps, total current must be less than 15 Amps)

300W/110V = 2.72Amps - So I'm safe.

For a 500W Heater - 500W/110V = 4.55Amps - Getting close to the upper limit.

For a 1000W Heater - 1000W/110V = 9 Amps - I would need the EB4

[phi delt reefer]

Originally Posted by abcha0s

Hey Phi Delt

I haven't done the bucket test, but your right to an extent. One of the things that seems to be happening is that the heaters are turning on and off. I think this is in part due to their close proximity to each other. I have their thermostat set at 81F (or close) and the Apex set at 78F, but even at 81F they are cycling. I think the radiant heat from the neighboring heaters is causing this. I thought that the water turbulence would be sufficient in the small sump chamber to avoid this, but perhaps not. I will move them further apart or set their thermostats higher.

The Apex Energy Bar 8 (EB8) is rated at:

8 independently controllable 120V Outlets (Max 5 Amps, total current must be less than 15 Amps)

300W/110V = 2.72Amps - So I'm safe.

For a 500W Heater - 500W/110V = 4.55Amps - Getting close to the upper limit.

For a 1000W Heater - 1000W/110V = 9 Amps - I would need the EB4

couple tests to see if what you are thinking is happening.

Get a normal mercury thermometer and test the water by your heat probes current placement (ie. verify the probe is accurate)

measure the temp in the hot spots you think you may have in your tank (ie. between the thermometers.

This equation will help you determine how many watts of heat you need for your system for what length of time.


equation has the following variables included

• specific gravity of sea water is 1025 kg/m3
• your total system volume is 300 gallons
• specific gravity of sea water is 3850 J/Kg*C

Watts = 4481361.50 x (change in TEMP[Celsius]/change in TIME[seconds])

obviously you need to sub in two variables to figure out the third.

so here are some 'measurements'

1. given Tony's example and your data if you wanted to raise the temp of you water 6 degrees C in 24 hours you would only 311 watts from your heaters.
2. if you used all 1200 watts of heaters to raise your system volume 6 degrees it would only take 5.802 hours.

figuring out how much heat is needed to maintain a temp would require heat loss knowledge Maybe when you get your system to ideal temp turn off the heaters and see how long it takes for the temp to drop exactly 1 degree Celsius (possibly use the data logger in the APEX?)