heat difference 250W and 400W

john37

Super Rad Member
Premium Member
hi guys,
currently i have 3 250W Mh over my 225 and i keep my tank between 77-79degrees. without chiller. If i change 2 of the 250's to 400W does anyone know how much warmer my tank will get?
please help me out guys. thanks
 
I am just getting into reef tanks but could you check your regular heater to see how much of the time it is on to see how much your tank could take without overheating.
 
Itt will be noticably hotter.
Depends how well vented u r, could kick up 4 degs
 
You are adding the equivalent to a 300 watt heater directed to the top of the tank, I would say it will run about 2 to 5 degrees hotter if do nothing other than replacing them. I would recomend to replace your fans with higher flow fans and try to keep your hood open on some places.
I use 2 400 watters with two high flow 120 V 4" cooling fans in a 330 gal system. Heaters never turn on and my chiller turns on 50% of the time to keep the tank between 78.5* and 79.5* F, house is aircon'd.
This is the chart of my current temperature swings
(picture updates automatically every hour)

aqimg1.gif
 
I agree with jdieck. Going with 400 watters is going to push the tank temperature up to 5F more if you do nothing to actively cool the water. I have a 90 gallon with 2 400W XM 20ks in a partially enclosed canopy. I need 4 120mm cooling fans blowing on the tank surface to keep my temperature at 81 degrees in a 73F ambient controlled by central A/C. I run no chiller. I have no significant heat being added from pumps. It's all due to the lighting.


jdieck, how do you get those nice graphs from your Aquacontroller?
 
<a href=showthread.php?s=&postid=7476087#post7476087 target=_blank>Originally posted</a> by Aquaduck

jdieck, how do you get those nice graphs from your Aquacontroller?
Dont want to divert the thread but I use a software to extract the data from aquanotes and then made a program that uses the data to write to x-cell which with macros charts the data into the server, another program updates html files that are uploaded to the internet. One program the status one runs every 15 minutes and the chart one every hour.
 
thanks for the info....one more thing. I have two temp readers...My aquacontroller jr and one of those rainbow lifegard big digital thermometers. they have a 3degree difference in temp. when my aqua jr reads 77 my rainbow big therm. reads 74. How do i know which is more accurate? am i gonna have to go get another one?
 
<a href=showthread.php?s=&postid=7476660#post7476660 target=_blank>Originally posted</a> by john37
thanks for the info....one more thing. I have two temp readers...My aquacontroller jr and one of those rainbow lifegard big digital thermometers. they have a 3degree difference in temp. when my aqua jr reads 77 my rainbow big therm. reads 74. How do i know which is more accurate? am i gonna have to go get another one?

That is very common. I also had differences when comparing the controller of the chiller, the Neptune and a manual digital one. I ended up buying a lab grade glass thermometer (Which by the way is not expensive) to find out which one was closer and adjust the settings accordingly.
 
jdiek, sounds complicated to get the graphs like that. Beyond my abilities. Oh well.

john37, you can calibrate your probes with icewater. Get a pitcher, fill it with ice then add water to fill it. Place the probes in the water and wait 1/2 hour. When the reading stabalizes, the temp should be 32F or zero C. Freezing water has a constant temperature of 32F until it starts melting or freezing completely. Just tweak the temperature offset in the ACJR to get it at 32F. That's what I did.
 
<a href=showthread.php?s=&postid=7477401#post7477401 target=_blank>Originally posted</a> by Aquaduck
john37, you can calibrate your probes with icewater. Get a pitcher, fill it with ice then add water to fill it. Place the probes in the water and wait 1/2 hour. When the reading stabalizes, the temp should be 32F or zero C. Freezing water has a constant temperature of 32F until it starts melting or freezing completely. Just tweak the temperature offset in the ACJR to get it at 32F. That's what I did.

It is a good way but partial one at that. That will set the zero but not the slope. In other words when reading 32* it will be accurate but as the temperatue deviates from 32*F the measurment may tend to drift away from accuracy, that is why the verification has to be done at two different readings.
Because the controller can only adjust one point (and assumes that the thermistor in the probe will be linear with the temperature change) that is why I try to do the calibration as close to the tank temperature as possible thus the need for a lab thermometer.
Having said that it will be more than the accuracy required for a healthy system even if it drifts 2 degrees. Just set your control parameters in the middle of the tank's acceptable range.
 
<a href=showthread.php?s=&postid=7477996#post7477996 target=_blank>Originally posted</a> by Aquaduck
I never considered the slope. I wonder how linear the temperature probes are?

They are usually good enough. I remembering testing the variation of two different Neptune probes and I got 1.5% over the range of 100* centigrade degrees on one and 2.5% on the other one. If zeroed at 0* (32*F) then at 26*C (79*F) that will be aprox a variation of +/- 0.4 of a *C on one and +/- 0.7 of a *C on the other.
Assuming the worst one then if you target 79*F the actual temperature could be between 77.5*F to 80*F and the better one between 78.1*F to 79.5 which is not bad.
So basically you could have between half to one degree plus or minus variation.
 
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