Heat buildup from pumps

[Mike Lang]

Folks, planning a new 125 gallon river tank setup. I'd like to use a high capacity pump, like a Mag Drive, 1800 GPH with the output split between a spraybar and the rest dumped into an Aqua Clear 500 power filter for an increased waterfall effect, instead of multiple power heads. A single pump is cheaper, and easier to hide in the tank than two or three large power heads. My concern is heat buildup. The pump I'm talking about dissipates about 145 watts, which isn't a lot in a tank that size, but in the summer it could be significant. I don't want to plumb the pump outside the tank if I can avoid it, for reasons of esthetics and simplicity. Anyone have similar experience that could help me figure this out??... I'm guessing perhaps a 5 degree F rise, but I'm hoping for less.

[crazy loaches]

Well if you must go submersible then your hand are kind of tied. The heat will be dissipated in the tank. So about the only thing you can do is to find a pump thats the most efficient, meaning lowest wattage for the flow you want. If its for in the tank, I'd just look at the high flow powerheads personally. For example the Koralia4 is 1200 gph and only 12 watts. A pair of these would probably do you well. http://www.drsfostersmith.com/Product/P ... atid=15955

Or look at the maxi-jet mod kits like the Sure Flow, just be aware these arent as loach friendly unless you do some mods like I just showed on another thread in the fw section. Of course with powerheads you wont get that perfect unidirectional flow.

Or if your not completely opposed, do what the marine folks call a closed loop system where you just have an external pump for circulation. Much less heat it transfered to the water since the water goes through a sealed compartment with just the impeller. The motor is air cooled and connected with a shaft. Something like the Sequence Snapper or Dart. However those will be more costly options, and you'd have to do some diy plumbing. I'm toying with the idea of a snapper or dart on a 40g long river tank for closed loop flow.

[Glostik]

For the closed loop, you could use any pump that can be ran outside of a tank, even MAG's are usable outside of the tank.

Also , alot of people use canister filters for closed loop. I plan on using some Eheim 2260's for my closed loops on my next tank.

[Mike Lang]

Thanks for the input. Yes, I know I could go with a closed loop and still get the unidirectional flow. Multiple power heads use much more space and cost more, but they are more energy effiecient. I was just trying to keep all the hardware in the tank for appearance purposes and the simplicity of a single pump is attractive. I may ultimately have to go that way though to get the results I want. I have looked at your mods on the other thread and very nice job. I know the new koralia's and Maxi mods give a lot of circulation, but it's not the directional flow I want.... I use an AC 500 power filter with a Mag 500 gph in one of my 75's with a Rena XP-3. The Mag output is plumbed right into the aqua clear which handles the additional 500g's just fine. All intakes are run to the left side, outputs to the right. While not a classic river tank setup, I was able to achieve the same result without tearing down the existing tank and starting over. Since the Mag 500 only dumps about 45 watts into the tank, it hasn't been an issue, but a Mag 1800 is 3x's the heat......Using an external pump in a closed loop is starting to look like the way I'm going to have to go for the directional flow and volume of water I need to move, without the heat issue. My other concern about an external pump is noise. It would be in the cabinet of course, but pumps make noise unless they're submerged and that kind of kills the whole tranquility thing, My wife thinks fish tanks should be seen, not heard!! Any suggestions for a high volume, at least 1500gph, QUIET pump??

[Glostik]

Very Large external pumps.

Good for ponds and multi tank setups.

I have 2 Maxijet 1200's, Eheim 2260, AC500, and Eheim 2217 on my 150 Loach tank. I have it setup so they all push water in a circular motion.

I also have a sump, with the return pump being a MAG 7.

I have a Koralia 4 also, but im not so impressed with it. Im going to mess with it some more.

[jones57742]

Mike:

I cannot find an efficiency curve for your pump.

Armed with the surface area of your tank, a previous thread concerning river tanks, your typical tank temperature and the maximum temperature in your home* I believe that I can come up with a WAG here.

If your configuration is different from the links posted by Martin in
http://forums.loaches.com/viewtopic.php ... 0&start=15
a brief description of the configuration will be beneficial.

TR

*what I am trying to ask is if you have A/C and if so what temperature is your maximum during the summer (ie. like 72F)?.

[Mike Lang]

G'Day Mr Jones. My river tank design will be essentially the same as Martin's, with some minor plumbing differences. I don't normally AC my house in the summer. It's not that I'm cheap, but I live in the woods and get lots of wonderful shade during the day, so the temperature in the area in question would typically be 75-77 on a hot day outside, which to me is comfortable enough. Assuming I typically run my tanks about 79-80 degrees I'd be getting heat LOSS most of the time. I tried doing calculations with watts to BTU's per gallon, to get temp rise, but clearly I didn't understand the math because what I came up with didn't make any sense.

[jones57742]

Mike:

What is the surface area of your tank?

TR

[crazy loaches]

Any suggestions for a high volume, at least 1500gph, QUIET pump??

Check my first post. I mention a couple sequence pumps. They are external, shaft driven & air cooled. Very efficient and quiet for the flow. They have a good reputation, and a 3 yr warranty. You will got a lot of flow though, even the smallest (the Snapper) with a very low head loss will be very close to advertised at around 2400gph. I have the Dart and am hapy with it in the family room by the TV. Its not perfectly silent, but very quiet, and the sound of my overflows are louder despite only having a 2" max drop and durso's. I've heard of a few other good quiet pumps, Iwaki, Velocity, a couple others I can't think of off hand... just remember though for closed loop if your just using it for circulation you dont need a high head pump. Many pumps are less efficient since they can push the gph you want but at 30 foot or more head, which is a waste just for circulation. Personally I check out the reef forums like reefcentral and look for reviews and recommendations on what pump for closed loop. You'll probably find hundreds or thousands of threads on the topic.

And if looks are of main concern personally I like to get all the equipment out of the tank! All you need to have in sight is the inflow and outflow plumbing, which hopefully you can get a color that blends well - I like the black background look and easy to hide anything thats also black, like ABS pipe, or pvc painted black, etc. Everything else is hidden in the stand/cabinetry.

One thing about the Sequence pumps though, they take a large input pipe, my Dart uses 2" on the suction side which is huge (cant remember if the snapper is 1.5" or 2")... so that might make it harder to hide. You might be able to Y two smaller pieces into the intake though, like perhaps two 1" lines would suffice, or 3, etc. which can be run down into the stand and then wye'd together into a 2" line going to the pump.

Calculating heat is tricky. For one thing we dont know for sure how much of the wattage your pump converts to heat, and this will vary greatly between pumps.

[jones57742]

[quote="crazy loachesCalculating heat is tricky. For one thing we dont know for sure how much of the wattage your pump converts to heat, and this will vary greatly between pumps.[/quote]

Tristan:

Hence my disappointment in not being able to find an efficiency curve for his pump

but

I believe that if he will post the surface area of his tank then I can come up with something better than a WAG.

TR

[Mike Lang]

Thanks for the input folks. The surface area would be about 9 sq.ft. for a 125 gallon, 72"x18" tank. Yeah, heat loss/gain calculations could be tricky...lots of variables. I'm starting to lean more towards Tristan's idea of a good external circulation pump. That all but eliminates the heat transfer problem, gets the hardware out of the tank, and is more energy efficient to boot. I did look into the Sequence pumps and the snapper could well work for my setup. By itself it would give me about 20x turnovers for excellent current and circulation. The plumbing IS a bit on the large side, but as you mentioned, there are ways to work with that and if not hide it, at least make it less noticeable. I too am a fan of black/dark backgrounds. It tends to give the tank more visual depth, doesn't distract they eye from the tank itself and helps to camoflage hardware, assuming you use things that are black/brown or grey.

[jones57742]

like a Mag Drive, 1800 GPH
The pump I'm talking about dissipates about 145 watts

Mike:

I googled for this pump and it does not dissipate 145 joules of energy/second.

The energy is distributed in the forms of kinetic energy, due to the mass and velocity of the water, and heat generation due to the inefficiency of the pump as well as energy losses in the pipes.

Based on the information which you provided, several WAG's (the largest of which was the pump efficiency) and my rudimentary spreadsheet analysis under the extreme air temperature condition which you cited the increase in water temperature will be 0.75C (1.4F) or less.

Please note this temperature increase is real WAG and that I anticipate that the temperature increase which you will observe may vary from 0.7F to 2.8F with a 98% probability of occurence.

TR

[Mike Lang]

Hello yet again!! Clearly your math skills are better or at least more extensive than mine. I'll have to take your word for it!! If, as you indicate, my worst case would be about a 3 degree rise, give or take, I could live with that...or should I say the fish could. Recently I had a bout of ICH...different thread...and had them up to 86-87 for two weeks. I aerated heavily and it didn't seem to bother the loaches at all. Even the S. American and African cats in the tank seemed to do alright with it, although I don't think they'd like it indefinitely. Didn't lose any fish and saw no signs of stress. I would suppose that a temp in the low 80's in the summer months wouldn't bother them too much and it would be intermittent , not constant. Thanks yet again for your assistance!!

[jones57742]

Clearly your math skills are better or at least more extensive than mine.

Mke:

Math is only a tool (much like a pencil) in the solution of problems associated with physical nature as per our understanding thereof.

TR

BTW Mike: Please excuse me here but just had to rectify.