Temp control

jahmic

jahmic

Reef Shark
M.A.S.C Club Member
#1
#1
Ok, so I have a (potentially dumb) question concerning temperature regulation in my nanocube.

I have a reliable 100w titanium heater that I ordered from catalina aquariums as well as a medical grade digital thermometer and probe. Both were in use for over a year, so I thought it was odd when the thermostat seemed to go bad when I placed the heater in this tank. Thermostat set to 78, thermometer consistently reads 75. I have another identical heater that I use to heat my r/o for changes, and figured I'd swap them.

When I placed my hand in the heater chamber, I figured out my problem immediately...the water in the chamber heats faster than the volume in the display, and thus cuts the heater off before reaching the target temp. For those unfamiliar with the tank, there is a constant level chamber in the rear sump on either side of the overflow. One houses my skimmer intake, the other houses the heater. I raised the thermostar to 80, tank temp is now 77.

What is the best (cost conscious) solution? Can I just set my thermostat on the heater for 82 to keep the display at 79? Or do I run the "risk" of allowing my tank to fluctuate that much daily. I'm used to my tanks being in the +/- 1 range, but am not sure how essential that amount of accuracy really is. I'm assuming this is why people use fancy controllers with probes...and though I'm just as attracted to the bright lights of new equipment, I'm hoping for a simple solution.
 
jahmic

jahmic

Reef Shark
M.A.S.C Club Member
#3
#3
Yea, I've been looking at placing it elsewhere in the sump...

The water level in the chambers on the far ends of the sump vary too much to place the heater there, and there isn't enough room in the overflow chamber.

I could place it in the very bottom of the sump and it would be golden...the only issue is that the cord is too short. This is my only gripe with the heater...the cord is maybe 40" long
 
dirtefish

dirtefish

Angel Fish
#4
#4
Running into a similar issue. I just ordered a controller so I can build a more decent heating system to try and avoid the problem.
I have a digi therm in the display tank near my overflow. I have 2 200w heaters in my sump. One is run off a digi controller built into the heater, the other is ghetto knob thermostat built into the heater. Pretty sure they are constantly fighting each other and the sump water heats and cools faster than the DT. Wishing that the probe on the controlled heater was long enough to run to display, but its not and I havent gotten around to extending it yet.
Really I am pretty nub at having a heating system that works well. I finally ordered a controller after having the tank almost two years and going through about 10 heaters. The new controller heater is the first "new" unit I have purchased the rest were hand me downs or cheap. I learned my lesson with that after losing some livestock.
But end question to my little rant is where is the best placement of the probes that will control the tank temp? I imagine running it to the display tank would be the best. And second as far as heater placement in the sump there was a huge difference when I moved it from the gaps in the baffle to my skimmers area. My guess the larger water volume retains the heat better than the heaters being in a high flow area. But this is just a guess.
 
jahmic

jahmic

Reef Shark
M.A.S.C Club Member
#5
#5
This should help:


(not my photo)

The heater is currently in the 'slot' to the left of the center overflow chamber. The center chamber has insufficient room for the heater. The "U" surrounding the center chamber connects the 2 constant water level chambers...my skimmer is in the one to the right, heater on the left. This whole area is low flow...though I'm wondering now if I could squeeze the heater in with the protein skimmer intake...this is if course assuming that the skimmer pulls enough water to increase the flow so that the heater works more efficiently.

I think my only solution is going to be to place the heater in the very bottom, between the 2 pumps. It's going to be a pain to fish it down there and try to secure it, but its probably the best option if placing it next to the skimmer intake fails.
 
jahmic

jahmic

Reef Shark
M.A.S.C Club Member
#6
#6
A thanks may be in order to Denvercherub for getting the gears turning...

This issue just came to light a couple days ago, but I had not noticed the discrepancy previously, and the tank has been up for almost 4 weeks.

So what's changed? I added the skimmer last weekend. I'm pretty sure that due to the design of the rear sump, and the placement of the skimmer intake, I effectively decreased the flow in the slot where the heater resides. Looking at that photo above, there would definitely be more flow in the slot where the skimmer intake is sitting...resulting in MUCH less flow where the heater was. I just used a flashlight and stirred up some gunk in the sump to watch the flow....and the water is nearly stagnant in the heater chamber compared to skimmer chamber on the opposite side.

I moved the heater so it sits right beside the skimmer intake and turned the thermostat back down to 78. The temp is holding at 77...so far so good!
 
jahmic

jahmic

Reef Shark
M.A.S.C Club Member
#8
#8
No apology needed...hope you get that sorted, sorry I don't have any suggestions
 
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