4300 Gallon Plywood Build (3600+ Take 2)

Now I remember.They are not designed to be continually used,24/7.And PVC is a poor heat conductor.
It will wear out the heat exchanger. Just wondering if you had found one that has elimented this problem.
Rinnai,Navien,and Rudd are the brands we carry.
A commerical one may solve this problem,but I'm not sure.

To keep the tank at even 84 degrees, it would barely be on once the tank was to temp.

Tankless hot water heaters are designed for intermittent on demand use. My use of it will be fractional compared to the use it would get from baths/dishes/laundry even with a small household.
 
Sounds like a good plan. Once it is up to temp,it probably won't be working much. I should have known you thought all of this through.I think pex would probably work better than PVC.But again,I'm sure you probably have or will research that more as well.
Can't wait to see water in it. It looks great.
 
So no ground loop geothermal heat pumps or roof top solar panels? Just kiddin' The PEX is a better alt. to the PVC though since it is made to carry heated fluids and conduct the heat through its skin. It's also available with an oxygen barrier, if your water heater manufacturer requires it.

I'm not a plumber but there are reasons why CPVC is required by code for domestic water use rather than PVC. There's probably something to do with degassing or such that ya might wanna check out...you know, in all of your spare time. Also if you use PEX it transfers heat much more efficiently if you provide it with an aluminum reflector since heat doesn't all rise (it's complicated).

http://www.radiantec.com/systems-sources/systems.php


I would also recommend brass valves over plastic. If you look hard you can get some pretty good deals on line. I would just try to stay away from the imports, you're project demands better.

When you work with framing lumber off the shelf from Lowes it was probably a standing tree a few weeks before and still carrying a good bit of moisture. As it drys most of the shrinkage is in the length but there is still some across the shorter dimensions. I doubt that it could effect your walls due to the amount of adhesive and screws, plus you weren't cutting and assembling all at once, but it's something to consider on the next one. Think about buying all of your lumber at once, placing stickers between all of the pieces and leaving the stack to air dry and acclimate in the area where it is going to live. Not critical I suppose but it could have had something to do with some of the phantom leaks that the other projects suffered from that didn't have as flexible a membrane as yours. Again, since you cut your stock and had it all in the house for a good while this doesn't have anything to do with your project, just general FYI. Not tryin' to give you an ulcer.

Anyway can't wait to see the fish in their new indoor lake.
 
I would never put any kind of metal, i.e. aluminum, in the tank. Too much organic material and oxidized metal creates some nasty stuff.

Brass valves over plastic used where? Maybe on the outside of the tank to plumb the pex to the tankless hot water heater, but NEVER for plumbing used with water inside the tank.
 
Sorry, didn't do a very good job of explaining. Total agreement with the metals and valves. I was suggesting the brass valves instead of PVC for your drains. The reflectors for the PEX weren't intended for inside the tank. They would only be used under the tank or a sump. I don't fully understand all of the complexities of your filtration system so it was just meant for reference.

The other issue with the PEX however is that the fittings are proprietary and require special crimping tools, etc. to work with. Sometimes the suppliers will rent them to you but it's best to check it all out in advance. Sorry for the confusion.
 
Once again, brass shouldn't be used for contact with aquarium water ever.

Nothing can go under the tank. It is directly on the concrete.

For the heating:

Tankless hot water heater plumbed to water pump plumbed to pex (or other tubing) in a closed loop. Thermostat turns on pump when tank needs heating. Pex or other tubing is snaked on a frame that is approximated 18" wide by 5' tall. The coil frame is hidden by the section of the tank shown in the attached pic. Water flows through the tubing and back to the hot water heater which heats it as long as the pump is running.

heat coil.jpg
 
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