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new tank, running a little hot

3K views 4 replies 3 participants last post by  conger 
#1 ·
Hello all, I've got a unique overheating question I haven't seen other places... I'm new to the forum, so I apologize if this isn't the appropriate place for this question :)

About a month ago, I got a new 90 gal (4' x 1.5' x 2') tank that I am using as FOWLR. My initial equipment (during cycling, before livestock) consisted simply of the basic overflow wet/dry sump filter, and a 300W heater. The pump is a Rio 2500 (55W). For lighting, I have a Coralife Lunar Aqualight on a timer (actinics on from noon-midnight, daylights on 3:00-9:00). The tank has a tight-fitting glass cover with small corners cut out for powerhead cords, and the light is up on "legs" about 2" to 3" up. For the first month, there was no temp problem; the heater kicked on when it needed to (desired tank temp 76F, room temp pretty constant at 70F) and the tank temp was stable.

Earlier this week, I started adding additional filtration and powerheads. I added a Coralife 18W UV ster, as well as a small (too small, probably :? ) ViaAqua PolyReactor for PhosBan and active carbon. The ViaAqua comes with its own tiny 5.5W pump that sits in the sump, pulls water into the canister, and returns the water into the sump. The UV is inline with the main return to the tank (of course). I measured the gph of the return to be ~225 gph, which "should" be pretty good for the UV sterilizer. I also added two Maxi-Jet 1200 powerheads inside the tank for circulation.

I finally noticed today that the temp is creeping upwards, despite the fact that the ambient temp in the room has stayed the same. I'm thinking it is because of the extra power consumption, but then again I didn't add THAT much to the tank, really just a 5.5W pump in the sump, two 20W powerheads, and the UV sterilizer.

So my long-winded question is (hey, I just read the "everyone read this" post and it said to be thorough with the description :)), do UV sterilizers significantly increase water temperature? I'd like to avoid adding a chiller any time soon... I'll put one in after a while, but I gotta slow down my spending on the tank! Anyways, this is the first time I've ever had an overheating problem, so I have no idea what to do about it, or even what is causing it. Today I turned off the UV lamp, and have opened the glass hood and stand doors to give as much air flow as possible, and see if that pulls the temp down temporarily.

Sorry for the super-long post, and thanks for any help that anyone can offer![/i]
 
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#3 ·
haha, thanks for the quick reply... i'm hoping that it turns out that UV sterilizers act like mini-heaters, and as a temp-fix (until I can afford a chiller, I suppose) I can just turn up my pump to increase the flow-rate through my UV unit. It would make it less effective, but for now that would be tolerable if it keep my tank from cooking! But thats my fantasy world...

If it turns out that its not just the UV, but an un-avoidable thing for my tank with the equipment I have, I guess I may have to go with an open top and put fans on it. It just surprised me, it doesn't seem like I added that much stuff, and what was once a stable tank temp increased by 6 degrees in ~3 days.

Anyways, I live in Florida, so if the tank is overheating in FEBRUARY, then in July-August its probably gonna be a steam cooker if I don't get a chiller :(
 
#4 ·
If you want to find out if the sterilizer is causing the added heating, just unplug the unit from the power. Allow the system to continue its course through the Sterilizer just without the power on to it, If you see no difference, then start looking for the next culprit.

Id wager that off-setting the tops for a short time to allow for more evaporation will help bring the temp back down as well. And yes, the added powerheads will also cause some temp increase too.
 
#5 ·
cool, I ran a little test over the weekend. The first night when I posted the question, I unplugged the UV sterilizer, and opened up both the tank lids and the cabinet doors overnight. When I got up in the morning, the temperature was back down to 76, which is what I want it to be at.

I left the UV unplugged, but closed the lids and cabinets for the rest of the weekend, and the temp is slowly creeping back up... its up to about 79/80 right now.

I guess the addition of the two 20W power heads into the main tank was just enough to slowly push the temp up. I'm not sure if the UV light is contributing heat when its on, since the temp is creeping up even when its off, but I guess in that case it doesn't matter :p. I'll just have to keep the lids open from time-to-time, and keep a close eye on the temp so it doesn't keep swinging back and forth and drive the fish crazy. I guess I'll have to bump the chiller up on my priority list.
 
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