Chiller size vs Tank size vs Insulating Capability in Coldwater Aquariums

[AquaticEngineer]

So it looks like I'll be selling the last lobster tank I needed to sell to be able to buy my big indoor display tank.

 

If all goes well, I'll have it gone wednesday morning, have cash in hand, and be going to pick up my tank wednesday afternoon.

 

My plan thus far has been to utilize the two lobster tanks I'll still have as the "sumps" for the larger indoor tank. The lobster tanks each have 1/2 HP chillers on them and are dual paned glass. They have little to no heat loss from them. The display tank is made of 1.25" thick acrylic and will be plumbed with return and overflow to the lobster tanks via schedule 80 PVC, and will have a closed loop in the bottom of it also using schedule 80 PVC. I imagine that 220 gallons of water always at a constant chilled temp being fed into a 300 gallon tank with 1.25" acrylic should be sufficient to keep everything stable and happy at a constant temp between 56F - 60F.

 

That's the jist of the system. Anyone see anything obviously wrong with the idea? Or anything I else I should consider?

AquaticEngineer

[Kool-cat]

You can adjust the temeprature of the lobster tank chiller right, to like 78F? Its possible that your tank will turn cold? Electricity consumption between the heaters and the chillers will be high and costly? If you lived in a really hot area it would probably be ok.

[AquaticEngineer]

You can adjust the temeprature of the lobster tank chiller right, to like 78F? Its possible that your tank will turn cold? Electricity consumption between the heaters and the chillers will be high and costly? If you lived in a really hot area it would probably be ok.

 

Total tank temperature will be running at a max of 60 degrees F, ususually more like 58F. There wont be any high current drawing lights over the tanks, and no heaters at all. Just a couple of my 50W LED spotlights , or Par38 bulbs, and all the pumps are external.

 

The lobster tank sumps will be housed in the garage, so it stays right around 54 degrees F most of the year with the exception of a few weeks during the summer. I keep my house temp a little warmer, right around 67F at the most while we are there, but drops down to 57F at night and when we are not there.

[bigmikey177]

You basically have a 1 hp chiller on your hands if you're gonna run both tanks. That should be more than sufficient for your setup. Those tanks reach down pretty low in temp right? If I remember those things reach to like 30 deg or so. Plus those tanks are well insulated. Maybe you might get a bit of sweat here and there but nothing major.

[AquaticEngineer]

You basically have a 1 hp chiller on your hands if you're gonna run both tanks. That should be more than sufficient for your setup. Those tanks reach down pretty low in temp right? If I remember those things reach to like 30 deg or so. Plus those tanks are well insulated. Maybe you might get a bit of sweat here and there but nothing major.

 

Yeah I had no sweat at all last summer on the lobster tank I was running, and the 1.25" tank inside is thick enough to prevent any sweating. ( Most people recommend 1" thick acrylic )

 

When I was testing my setups last summer I took my one tank all the way down to like 34F in June and didnt get any sweating. It really depends on how much moisture is in the air, and my setups are darn near sealed in the garage. I've had less than a gallon total of evaporation on the 110 gallon tanks in over a year.

[AquaticEngineer]

WOOO HOOO Just sold the last lobster tank I needed to flip to get money for the new tank. Got the money in my pocket and if all goes as planned I should be picking up a 60"x24"x48" tank made of 1.25" thick acrylic tonight

[C-Rad]

Congratulations! So did you end up earning enough money flipping lobster tanks to completely pay for the two you kept, plus your fancy acrylic tank? Maybe you can raise abalone in your two sumps, and make an annual profit with your hobby

 

As was stated, you have 1 hp of chiller available, and only about a 10 degree difference between your water temp and your room temp, so you should have enough chiller power available to compensate for the amount of heat that will leak into the system from your room air. But you need to realize that you have a lot of surface area per gallon because your acrylic tank, while holding 245 gallons (inside dimensions) is flat and slim compared to a 245 gallon cube. You also need to add the surface area of the pvc pipe that makes the trip from the garage into the house. The load on your chillers is proportional to the product of the amound of surface area your system has and the temp difference. A high surface area, and a normally small temp difference, means that doubling the temp difference could more than double the load on your chillers. I think your system will be vulnerable to high room temps because of the high surface area, and the lousy insulating quality of acryilc, so keep your eyes open on the first really hot day to see if your chillers get overwhelmed, and maybe leave the AC thermostat set at 72 if you go on vacation during the summer. It might be good to wire a timer (old analog electric clock from the thrift store?) into each of your chillers to have an idea of how many hours per day each one runs typically. If they ever run more than 12 hours per day, you might be working them too hard.

 

Another good reason to wire "hours of use" meters into your chillers is so that you will know if one of them is carrying more than its share of the load, and might wear out sooner.

 

The weak link in your system for sweating will be the PVC pipe, so you probably want to insulate it. If it sweats inside a wall, you could have mold and/or dry-rot problems.

 

I like to insulate everything I can, as much as I can. Not just to prevent sweating, but to prevent paying higher than neccessary electricity bills, which are a form of taxation, at least here in California. The cost goes up exponentially with usage (socialist bandits!). I would insulate the PVC pipe, even if it would never sweat, and so I would use the cheaper schedule 40 instead of the thicher schedule 80, and insulate it.

 

I was amazed that even after making insulating three sides of my tank, and using double pane glass on the remaining three sides, and using an air-cooled pump instead of a submersible one, that my 1/4 hp chiller still produces enough heat to make my living room uncomfortable hot most of the year if the AC isn't running. You may find, especially in the summer, that the air in your garage gets very hot, and that a ventilation fan in the garage is a good idea. Garages also tend to have more than their share of chemical fumes and carbon monoxide, so ventilation will help keep that stuff out of your water.

 

If you discover that your chillers are working hard, but not too hard, keep in mind that a failure of one chiller will probably happen during a heat wave, leaving only one to carry the largest load ever. The best first aid for that situation would be to insulate all sides of your acrylic tank until the heat wave is over, so you might want to have a plan to do that if the need ever arises (you can use sleeping bags (without scratchy metal zippers, bubble wrap, blankets, or buy two 4' x 8' sheets of insulation board at Home depot)

[AquaticEngineer]

Congratulations! So did you end up earning enough money flipping lobster tanks to completely pay for the two you kept, plus your fancy acrylic tank?

Yup I came out $100 overall after the last tank sale, and the one I sold yesterday gave me enough to buy my big acrylic tank

 

Maybe you can raise abalone in your two sumps, and make an annual profit with your hobby

Definitely not out of the question, I'm going to be keeping a lot of my live food for the display tank out in one of the "sumps", so throwing nori in and growing abalone isn't too far off.

 

As was stated, you have 1 hp of chiller available, and only about a 10 degree difference between your water temp and your room temp, so you should have enough chiller power available to compensate for the amount of heat that will leak into the system from your room air. But you need to realize that you have a lot of surface area per gallon because your acrylic tank, while holding 245 gallons (inside dimensions) is flat and slim compared to a 245 gallon cube. You also need to add the surface area of the pvc pipe that makes the trip from the garage into the house. The load on your chillers is proportional to the product of the amound of surface area your system has and the temp difference. A high surface area, and a normally small temp difference, means that doubling the temp difference could more than double the load on your chillers. I think your system will be vulnerable to high room temps because of the high surface area, and the lousy insulating quality of acryilc, so keep your eyes open on the first really hot day to see if your chillers get overwhelmed, and maybe leave the AC thermostat set at 72 if you go on vacation during the summer. It might be good to wire a timer (old analog electric clock from the thrift store?) into each of your chillers to have an idea of how many hours per day each one runs typically. If they ever run more than 12 hours per day, you might be working them too hard.

 

Another good reason to wire "hours of use" meters into your chillers is so that you will know if one of them is carrying more than its share of the load, and might wear out sooner.

Good call, I will do that. It'll be nice to know.

The weak link in your system for sweating will be the PVC pipe, so you probably want to insulate it. If it sweats inside a wall, you could have mold and/or dry-rot problems.

Luckily the way it is setup it will only have to pass straight through 1 interior wall and then dump into the garage tanks. The PVC itself will be exposed inside of a closet that I can access the overflow from as well so I was planning on wrapping all the pipes. Also going to use the thicker schedule 80 pvc.

 

I like to insulate everything I can, as much as I can. Not just to prevent sweating, but to prevent paying higher than neccessary electricity bills, which are a form of taxation, at least here in California. The cost goes up exponentially with usage (socialist bandits!). I would insulate the PVC pipe, even if it would never sweat, and so I would use the cheaper schedule 40 instead of the thicher schedule 80, and insulate it.

I never thought about it that way, I guess if I am going to insulate it anyways I could go with the schedule 40.

 

I was amazed that even after making insulating three sides of my tank, and using double pane glass on the remaining three sides, and using an air-cooled pump instead of a submersible one, that my 1/4 hp chiller still produces enough heat to make my living room uncomfortable hot most of the year if the AC isn't running. You may find, especially in the summer, that the air in your garage gets very hot, and that a ventilation fan in the garage is a good idea. Garages also tend to have more than their share of chemical fumes and carbon monoxide, so ventilation will help keep that stuff out of your water.

Oh yeah for sure. I have a north facing window in the garage that I use for ventilation. I also have really high ceilings in the garage ( like 20ft) so alot of the heat rises and I was going to install an exhaust fan up near the ceiling of the garage.

 

If you discover that your chillers are working hard, but not too hard, keep in mind that a failure of one chiller will probably happen during a heat wave, leaving only one to carry the largest load ever. The best first aid for that situation would be to insulate all sides of your acrylic tank until the heat wave is over, so you might want to have a plan to do that if the need ever arises (you can use sleeping bags (without scratchy metal zippers, bubble wrap, blankets, or buy two 4' x 8' sheets of insulation board at Home depot)

That sounds like a pretty good emergency plan, I'll have to put together a kit for that. I was also thinking of insulating the back side of the acrylic tank since it wont be viewable anyways.

 

I've also decided that I am going to make an attached false background inside of the tank on the back and overflow side using the spray foam/zoopoxy/aragacrete concept. I think it'll add alot to the tank with such a huge backside of the tank, and its 2 less sides of the tank I'll have to buff out

[AquaticEngineer]

Oh yeah, but after all the tank flipping and money saving I've done to get to this point, I have to wait until the end of the month to buy the tank.

 

My wife just went back to work on Monday from maternity leave so her first paycheck will only be a 1/2 paycheck. So I have to hold onto all my cash "just in case" says the wife Why does she always have to make so much sense......

 

On another weird note, I was contacted by a local guy who has a video production company who wants to come and film 4-6 hours of footage of my tank to use in a high definition DVD.........and he wants to PAY me to do it He came to check out the tank yesterday afternoon and we spent a couple hours talking about how we could move a few things in the tank, and setup the garage for the right lighting and such.

 

It'll take up a whole sunday a couple weeks from now, but how F-ing cool is that???