Heater not heating Display Tank

[idisc]

Good Morning Everyone!!

I am not new to salt or tanks by any means, but I figured the topic would get the most attention here.

I recently got a 40B setup with a 20H sump and a 300watt heater. I placed the heater in the sump like I have with many tanks before only to realize the tank had gotten down to room temp..70F

I initially thought the heater was not plugged in, but it was. I then noticed that the heater would kick on and off in the sump..

Figuring the heater was bad, I replaced it last night and I am still having a similar issue with the Display not getting heated.... CONFUSED ....

Tank has an 700GPH Overflow from glass holes, and I have no clue what size the return pump is, but it has a decent flow back into the tank.

I have not taken a temp reading from inside the sump yet (work long hours), but I am guessing maybe the sump is getting to temp causing the heater to turn off...but if it is getting to temp then shouldn't this water be getting to the DT...

Any and all suggestions appreciated.

 

[gone fishin]

That is odd. Are you sure the return is pumping to the DT? The only thing I can think off of the top of my head is poor circulation. Assuming the heater is working but I find it hard to believe you got to dud heaters in a row.

 

[Dkuhlmann]

I guess you set the temp by the dial on the heater? I never do that because they are 9/10 times wrong. I only set my temp by a digital thermometer. I suggest you get two of them, rather cheap at Walmart or other places. Then see what your temps are in both the sump and the DT. Set accordingly. There are temp controlled units you can get to turn the heater off and on with a set temp which would be a more accurate way to go.

 

[idisc]

Well of course it is plumbed to the DT lol. The tank is running fine, I just can't get it to heat up properly.

When I get home at 8pm tonight I will put a temp probe in the sump fuge area where the heater is and see what reading I get. Even if the return pump was low...the water should still circulate properly. I mean...a 300w heater could not heat up the tank...I have a 100w in there now.

I assumed the water was getting to hot and constantly shutting down the heater...but like I said...this hot water should have made it to the DT.. really confused.

 

[idisc]

Yeah I understand what your saying about the temp setting..but when I set the heater to 79F...and the tank is 70F..I don't really think its a error in the heater, but I will check into it.

I have a digital temp gauge in DT and I have a standard mercury glass one in DT as well. When I get home I am going to toss the glass one in the sump and get a reading.

 

[fermentedhiker]

If the heater is cycling on/off then apparently it "thinks" it's up to temperature. That leaves you with two possibilities. That the heaters thermostatic control/sensor is faulty or that the sump being so small and the heater so larger it can heat the sump water up to temp and if the flow through the sump is particularly low it isn't sufficiently circulating the water.

I suppose another possibility is that your return is located too close to the overflow and the warm water from the sump is getting sucked back down the overflow and the rest of the tank has established a kind of thermocline prevent adequate mixing.

Personally I don't run heaters without a separate controller anymore. Even if I'm not going to run a full controller like an apex I'd just get one of those finnex heater controllers or build one using those ranco controllers off of ebay.

I know a lot of people put the temp probes in the sump with the heater but I prefer having the sensor in the display.

Just a couple thoughts.

 

[Dkuhlmann]

I have my heater in the overflow return section of my sump. This way the cooler water from the tank return will make it go on. If your heater is in any of the other sections it could be warming up thus making it turn off. Just grasping for something here LOL. I've never heard of your problem before.

 

[shifty51008]

What brand heaters? A 300 watt heater should be way plenty for a 40 gal. It is pleny for my 200 gal total water.

I agree though i would deff look at buying a temp controller. The ranco's are very reliable and decent priced.

 

[chimmike]

one of two things:

1) Not enough flow turnover to the display. You don't seem to know what the exact flow is from your pump, and i'm guessing you haven't accounted for head loss
2) the heater is malfunctioning, period. I'd try a different heater before worrying about a temp controller. Heaters can/do fail.

 

[idisc]

I have tried 2 heaters. I don't know the return gph, as the thing doesn't even say anywhere on it..which I find odd. When I get home I will try and lift the return nozzle and fill a 1 gallon jug and get an estimate on the pump.

I could also move the heater from the fuge area to the drain section and see what happens. Thanks for the suggestions.. still baffled lol

 

[ZeeSparrow]

Will be interested in knowing what the temp in the sump is... might be that second heater is bad, too. Are they the same brand? I've had issues with two recently myself, though both of mine just "stuck on" (one was in my brute for WC so no issue, and the other was only half of what I used to heat the tank and didn't raise the temp too much before I caught it). A controller is really helpful, be it a temp controller only or the full deal like Apex.

 

[idisc]

Different brands, the 300watt is only a month old. and the 100watt is new. Different brands... I am wondering the same. I might be able to get the temp before I get home if I can get the woman to check it for me lol

 

[Frostyfishman]

Put the heater in the display tank and see what happens. If that shoots up in temperature the problem it's due to the flow and volume in the sump.

 

[Coelli]

I have tried 2 heaters. I don't know the return gph, as the thing doesn't even say anywhere on it..which I find odd. When I get home I will try and lift the return nozzle and fill a 1 gallon jug and get an estimate on the pump.

I could also move the heater from the fuge area to the drain section and see what happens. Thanks for the suggestions.. still baffled lol

Move it to the drain, or at least start by moving the temp sensor. You want it to be reading what's coming directly from the tank. I suspect the heater is really overpowered for your tank. I have a 300w on a 65g DT and 20g sump with a 30g display fuge plumbed in and it keeps the display fuge at the same temp as the DT since they're off the same return. The heater only turns on for a second or so at a time, fairly frequently, to keep the tank between 77 and 77.5. 300w without a separate controller is kind of asking for it to eventually cook your tank anyway if it malfunctions. :| As others have mentioned, because it's so big it's probably heating up the small space in the sump before the sump can turn over.

 

[chimmike]

I have tried 2 heaters. I don't know the return gph, as the thing doesn't even say anywhere on it..which I find odd. When I get home I will try and lift the return nozzle and fill a 1 gallon jug and get an estimate on the pump.

I could also move the heater from the fuge area to the drain section and see what happens. Thanks for the suggestions.. still baffled lol

well then you've just told us the flow isn't sufficient

research the brand and model of the pump and you should find the specifications including head losses per foot. Add in a little bit for any bends in plumbing and friction losses and you may not have sufficient turnover.

 

[Sk8r]

If you've got an Eheim Jager heater, ---there is a calibration setting as well as a temperature setting. If you've moved the wrong thing you may have thrown calibration off. I did that once.

 

[WaReefer458]

I run a 150watt in my sump on my 40. I also have 900gph turnover. I think the heater is just too big. Get a 100 or 150. But double check your temp in the sump. My guess is you just need to adjust it. My eheim has to be set at 82 to get my tank to 78 deg. Goodluck

 

[idisc]

Well after finally getting ahold of the past owner of this tank he told me the return pump was from harbor freight.

We have concluded that it is either a 68393 which is 6.5"x2.84"x4.02" @ 620GPH or a 68395 which is 5.09"x2.85"x3.19" @ 264GPH - These are dimensions I took off from amazon. I will measure the unit when I get home.

Chances are it is the 68395 and is far below what is even recommended for a tank this size. Figure in about 3ft of head loss to the return it's self and this thing is problem doing closer to 100 GPH if it is the case.

If it turns out to be the 600GPH unit I will adjust accordingly. Regardless I will be trying to run the heater in the drain first and then the DT 2nd until I get a Mag 7 hooked up.

Everything is currently soft plumbed as I didn't have time to hard plumb like my other tanks. I will keep you all posted when I get home around 8pm tonight.

 

[shifty51008]

Hopefully that pump was saltwater safe.

 

[WaReefer458]

replace it with a mag7. about 80 bucks and will get some really good tank turnover. it will just come down to how much your drain will handle. I have a 1.5" drain on my tank and it barely handles 900.