Conundrum: recirculating sump water causes temperature spike?

[dleute]

A few days ago I installed my custom manifold. The manifold has 3 ports two of which currently just circulate back into the entry section of the sump. The 3rd goes to a GFO reactor which outputs to the return section. The manifold is driven by a pump in the return section (separate from the return pump).

As soon as I installed this, the tank temperature spiked 4+ degrees over the next 6 hours. The tank is still cycling so it wasn't an issue. I added a program to the apex to keep the heaters off above a certain temp.

I am using two cobalt neo-therm 150w heaters. These are supposed to be very good at producing stable temperatures (according to BRS). I have now reduced their setting to 78 and the tank is still at 83 (I was running hot for the fishless cycle, so again, doesn't really matter).

More water is flowing past the heaters (in the first section of the sump), but this water should already be at the temperature the heaters want. So the thermostats should be shutting them down.

The two pumps in the return section could obviously be adding heat. But it seems odd to see such a spike purely because of a recirculation change.

I should note, it is also abnormally warm outside this week. So some of this could be environmental. The house temp has not moved much if at all.

Thoughts? Am I missing something obvious? Can recirculating sump water cause this kind of spike?

Thanks!

 

[ca1ore]

No. It's either heat from the new pump or just ambient temps. Or maybe both.

 

[dleute]

No. It's either heat from the new pump or just ambient temps. Or maybe both.

Are sicce silent 1.5 known to run hot?

 

[PilotMaximus]

Are sicce silent 1.5 known to run hot?

Most Italians I know run a little hot. jk,,,,sorry.....but seriously. Very few heaters are actually right. My heaters work well but the indicated temp and actual temp are off about 4 degrees like yours. May as well set your heaters or even crank them up and use your Apex as your heater controller. Thats whats its there for. Or at least one of the reasons.

Heres something I found real quick that might help
http://www.reefcentral.com/forums/showthread.php?t=2039628

 

[PilotMaximus]

Crap sorry I guess you wernt trying to fix how to keep the temp down rather than why it went up in the first place. So on that..... happy hunting.

 

[dleute]

Crap sorry I guess you wernt trying to fix how to keep the temp down rather than why it went up in the first place. So on that..... happy hunting.

4-5 degrees off seemed extreme to me. Also, the power log clearly shows the heaters still heating at that point in time.

Programming apex is easy for me (I'm a lead software developer by day). I'm actually only using the apex as a backup if the temperature rises too much (it will kill power to the heater). I'd rather have the neo-therm self regulate so it's not constantly going on and off (electronics generally do better when not having their power cut constantly). I will eventually setup a notification if it should be heating and isn't drawing power (heater failed).

Yeah, getting the temp where I want it won't be a problem. I'm just surprised at how much that change increased the temperature. It makes me very glad I have seneye and apex monitoring the system.

I also may not need heaters at all. The heat has not reduced much. I just hope I don't need to spring for a chiller. There just isn't any space for that.

--Derrek

 

[luvreefs23]

I don't know why you wouldn't just use apex to turn heaters on and off thru apex. Heaters are cheap and easy to replace. I've had eheims turning on and off for years without needing replaced. Plus make sure your temp probe isn't to close far from heaters. I had mine to close in the beginning when I set my 120 up and they turned on and off constantly. I'd also make sure your turnover thru your sump isn't to slow and not properly mixing the heated water with tank water.

 

[luvreefs23]

Also I use a sicce silent 1.5 as a mixing and waterchange pump and after pumping 5 gallons and picking the pump up to remove from bucket I was surprised on how surprisingly warm it was but can't see it creating that big of a temp fluctuation in a large tank. Sicce 1.5 also seems small to feed a manifold. Maybe working to hard and getting a lot hotter than you realize

 

[dleute]

I don't know why you wouldn't just use apex to turn heaters on and off thru apex. Heaters are cheap and easy to replace. I've had eheims turning on and off for years without needing replaced. Plus make sure your temp probe isn't to close far from heaters. I had mine to close in the beginning when I set my 120 up and they turned on and off constantly. I'd also make sure your turnover thru your sump isn't to slow and not properly mixing the heated water with tank water.

The probe is in the last sump section and the heaters are in the first. The flow is likely part of the problem as my sump is small with the drains close to the baffle and running the manifold outputs back to the first section likely corrected flow issues. The return pump is a mag drive 9.5 with a gate valve that is currently fully open. (I'm going to remove the gate valve and switch to a sicce pro to free up the mag drive for something else).

Neo-therm heaters have electronic controls that would be more sensitive to power flickering than a basic heater. As a rule, anything that is electronically controlled and self regulating shouldn't randomly have the power shut off and turned on (possibly rapidly). Basic heaters have no boot sequence, no electronic programming at all. These I would be comfortable under full apex control (there is an argument to be made that apex controlling analog heaters could actually extend their life. not sure it's a valid argument, but it could be made). Neo-therms are probably designed well enough to deal with it, but I don't see the point when the neo-therms are exceedingly good at maintaining stable temperature (Again, BRS test results). They were so good BRS ran the test again with different equipment to verify it.

Besides, I want apex to assist, not to implement where possible. My ATO is the tunze osmolator even though I could have programmed an equivalent ATO on apex. I want there to be some redundancy. I don't want to trust apex to everything and then have that fail.

Right now, if the heaters failed, the apex would help me know/fix it. If the apex failed, the tank would be fine running on it's equipment (assuming it still had power from the eb832 powerbar with fallbacks active).

The likely hood of an apex + other equipment simultaneous failure is much smaller. Even then, I *still* have seneye to back up that in terms of notification.

Both redundancy and not trusting electronics in power on/off situations are the reasons I don't just use the apex.

That's my 2 cents. But I work in technology where having only one backup is not sufficient.

--Derrek

 

[dleute]

Also I use a sicce silent 1.5 as a mixing and waterchange pump and after pumping 5 gallons and picking the pump up to remove from bucket I was surprised on how surprisingly warm it was but can't see it creating that big of a temp fluctuation in a large tank. Sicce 1.5 also seems small to feed a manifold. Maybe working to hard and getting a lot hotter than you realize

I haven't touched the thing since I put it in. I just observed the trend in apex/seneye. It's fine if it runs hot. Just surprised me.

How do you use it as a mixing pump? do you just dump it in the bottom of a bucket and let the water coming out the top of the pump do it?

I have some hydors for my brute mixing can. They spread the flow pretty well. Speaking of which, I need to reduce the temp on that as well.

--Derrek