very odd indeed!

When my old 135g tank was up, I never had to run a heater in it, in fact always had to have the chiller on even in the winter time! The new tank has been up now for 3 weeks. We decided to see if we could not run the chiller (did not think it would be possible...4 250W MH) but instead of warming up it is FREEZING!!! We got the shipment from reef cleaners yesterday and had to run and find a heater quickly. It is amazing that most LFS do not carry heaters for 135g tank! I did finally find the one that we wanted, the JBJ 300w True Temp titanium........the water temp was actually 70 yesterday morning even with the all the MH running .....got it up to 78 quickly with the heater and got the cuc in. Just wondering what the difference this time is. I am not complaining, would rather run a 300w heater versus a 1/4 hp chiller any day!!!

 

Wait!... so it is the same 135g volume and the same equipment?
4 250w metal halides should really warm that up. Maybe it will take some time though due to the water volume. But if the water keeps getting cooler, the heater is a must, IMO.
I'm not sure, if it is in fact the same water volume you used to have before, why is it running cold now? Maybe, if you used newer pumps they're more energy efficient, and don't add as much heat from friction as your old pumps use to do.
It is strange regardless.

 

actually it went from 135 to 125! Same pumps, same bulbs! the only thing that is not in there is the big pump for the chiller!

 

That is very strange, dude. I'd be lying if I said I knew the reason. How about your ac? Do you keep your place cool?

 

How have the surface areas of the tank and sump changed? More surface agitation, more exposure to air, less insulation from the tank itself? Better flow design?

Don't know whether it is good or bad although using the chiller less sounds like an energy savings to me.

 

There's a couple of things you're not taking into consideration.

PLUMBING:

They combined 2 1" drains at one T-Fitting and dropped it straight down from that fitting 5 inches underwater into your sump. Merely dropping 1 drain that deep underwater would introduce back pressure and slow down the draining capability of the overflow. Combining 2 drains and forcing the water to "fight" coming from both directions prior to going down to the sump created even more back pressure. That is the reason that ball valves were necessary on the return plumbing the throttle back your return pump. That is the reason you needed so many Hydor Korallias. Now that you are getting decent flow from your return pump, you don't have to have 5 Hydor Korallias anymore. Beyond that, were they drinking when doing the plumbing? I've never seen so many 90's used in my life. When plumbing a tank, one should use a 90 only when necessary.

PUMPS: You are running 2 Hydor Korallias now....not 5. Each pump adds heat.

LIGHTING:

You aren't at your full photoperiod yet. You have 4 250 watt MH's.

CHILLER:

The tubing on your chiller was ribbed tubing. This created back pressure on the chiller's closed loop. As a result, a larger pump was necessary to offset this backpressure. The pump on the chiller introduced heat. (Merely changing the tubing on your chiller would have allowed a smaller pump which would have mean your chiller would have been on less often). Merely having the chiller sitting right next to the tank makes it less efficient because it's exhaust was heating up the room that the tank was in (causing the tank to heat up, causing the chiller to run). That's why if possible, chillers should be ported to the outside.

 

That explains a lot. Much less heat being created and greater flow through the sump.

FWIW my heaters (350W total) run most of the time on my system. I have 3 Koralias (2 x 1050 and a nano) for in tank circulation and a Rio 8HF for my return pump with another Koralia (a nano) running in the return section to keep surface slime from forming. I have a lot of surface area with my canopy being open topped and a 40 breeder as the sump with the back of the stand being open. I also keep my place at 68 to 72.

 

Ah... so there's the answer to the magic trick!

 

The plumbing they built was so Rube Goldberg it was amazing. Even when I build a manifold, it's simpler than that. Basically, if a plumbing mistake could be made, they made it.

Now, to do a water change, all she has to do is rotate a ball valve now and turn it off after 5 gallons. Once her fish room is done in the basement, it's going to get a lot easier.

 

That makes sense.....i was just thinking how odd it was!