Heating Cost for Large Tank?

[chicken]

I agree the risk is low but it grosses me out to think I am showering or cooking my pasta in stagnant water that could have been sitting around for months in heating loop in my tank sump. On top of that most of the good circulation pumps for these type systems are cast iron and are going to add rust into the water supply as well. If you have a tank this large that you need a gas heating system for why not just spend the extra $500 to put a dedicated heater in. Tapping off of your tank water heater that is not rated to handle radiant heating is just going to cut its life in half and that's going to cost you atleast another $500 to replace it in 4-6 years. Just my opinion. I just wanted to make sure everyone understands both sides of the story and can make their own educated decision as most people don't know all of these details. Thanks

 

[Carpentersreef]

Right. - and that's a good point you bring up, any modifications should take into consideration the load that a recirculating pump would put on the system. Recirculating pumps should never be used with on-demand water heaters.
In the case of having water sitting in pipes for a period of months, I would suggest putting in a recirculating pump that circulated water through the system at least once each day, long enough to completely flush the system with fresh water. Recirculating pumps should come with a timer built in.
As far as a separate dedicated heater, not all mechanical rooms have the available space for 2 boilers, plus your gas meter and piping will need to be sized properly in order to accommodate peak demand periods.

 

[chicken]

About half of the tankless/on demand heaters are certified for radiant heat use like this. The example of the takagi Jr. above like I use is covered by a warranty even in this setup. I don't know of a tank water heater that is though. As for the pump you need to be very careful and have redundant thermostats with a setup like this. That little takagi of mine is equal to 35,000 watts electric heaters. So relying on a built in timer scares me because if it sticks on for even 30 minutes on a 300 gallon tank you are going to cook everything. I run dual ranco thermostats in series so both have to click on for the pump to start. A single ranco and your normal aquarium controller in series with it is safe as well. A single timer built into a $100 pump I would not trust with all of my livestock. I also have a second pair of rancos in series with 2,000 watts of electric heaters just incase something goes wrong with the gas setup. In the 6-7 years of the gas setup the electric heaters have never kicked on but I have had to replace them twice as they have not worked when I test them every 6 months or so.

 

[Carpentersreef]

I was referring to the built in timer for use as keeping the pipe water fresh in a domestic use setup only. I disabled the timer in my aquarium setup.
If one was to use a hot water heating coil to heat the aquarium, it should be sized appropriately so any heating is done gradually.
My heating loop took 9 hours to increase the temperature 6 degrees celsius, if I remember correctly.
To regulate heat in a large tank, I think the tank should also have a cover.
My tank is a 1" acrylic 600g and the covers give it a great deal of temperature stability.
I have had a number of titanium electric heaters split open in the sump before, exposing copper wires to the salt water, so the move to a hot water loop was an easy choice for me.
I already have radiant floor heating and solar hot water plus a gas boiler. The added load of heating the aquarium wasn't significant.

 

[sfsuphysics]

I agree the risk is low but it grosses me out to think I am showering or cooking my pasta in stagnant water that could have been sitting around for months in heating loop in my tank sump.

Months??? Wouldnt/shouldnt water cycle through multiple times per day? Or am I missing something about how they work, or perhaps I live in a climate that the tank needs to be heated every day ofvthe year

 

[chicken]

The coldest winter I ever spent was a summer in San Francisco..

I am 30 minutes east of you and from about April - November my heater does not kick on. This is the same for a lot of other people in other parts of the country as well.

 

[sfsuphysics]

The coldest winter I ever spent was a summer in San Francisco..

I am 30 minutes east of you and from about April - November my heater does not kick on. This is the same for a lot of other people in other parts of the country as well.

Yeah figured that might be the case, although makes me wonder if you dont need to heat your tank nearly 9 months out of the year is a gas heater system real all that necessary. Where as me heating a tank all the time it would possibly be much more advantageous. Either way something Ill need to consider when I get my system back up

 

[chicken]

It's about 6 months a year it looks like with regular usage. I would not be surprised if it kicks on every so often on other months. My heating system was around $1100 to build if I remember at the time. My peak monthly bills were over $350-400 a month for just heating the system. Gas worked out to like $20 a month. So it more than paid for itself in the first season. I was looking to tear down the tank unless I could get this working as it was just to much monthly costs. Our utility rates have dropped somewhat since then so it the ROI is not quite as fast but still within a season I suspect.