Backyard Aquaponics
A place to discuss aquaponics

Anyone have experience using a regular hot water heater plumbed directly in the loop to heat their AP System? I think now days the tanks are fiberglass lined, the fittings may be galvanized, but would that be enough to be toxic?

Anyone succesfull doing this?

Neal

maybe you could presoak the galv fittings to cut down on anything they carry but im not sure if WH will go down low enough on temp or not.

and it sure would have to have a really good filtering arrangement.

these are just my thoughts on your topic but im way newb so surely get veteran advice before adding the WH

best regards, john

It should be doable, a lot of koi enthusiasts heat their ponds using domestic gas boilers, central heating pump and a heat exchanger.

Think many are still copper.... or have brass connections... I wouldn't...

Another major problem is the water temperature.... usually at least 60 degrees... how would you modulate the inflow and cut off at desired tank temp??? ... let alone the issue of scolding the fish....

If you could pump through some sort of stainless steel heat exchanger... maybe...

Convert it into a hydronic heating system, using PEX or EPDM tubing touching the water. You bypass the toxicity threat as there is no direct contact and you can run the lines in your growbeds, just as the Freshwater Institute did or in your raft ponds, as most shrimp farmers do. You will need an expansion tank, a recirculating pump, an air bleeder, a pressure valve and a sensor to turn off/on the system. The hydronic heating system is in my second prototype.
I would also suggest mounting the hot water tank outside of your greenhouse, wrap it well and insulate the outside pipes. I know that capturing the extra heat is tempting but there are the threats of fire and explosions. You have to remember that plants gas off pure oxygen, which is highly explosive and with an enclosed greenhouse environment, oxygen can build up quickly. Regular greenhouses use CO2 generators for the plants but in AP, you use the dissolved CO2 gasses from fish respiration in the water for the plants, some of that will offgas into the atmosphere but you're still looking at a high oxygen ratio.
Just be safe.

AFAIK rupe, hardly any are copper any more, scrappies don't bother taking them from hard rubbish anymore, they usen't to last 2 minutes.
Mine was stainless = OK and brass fittings we found were OK didn't we? I dunno why, perhaps because the alloy bond reduces corrosion.

Kewl.... can't remember how the discussion about brass turned out...

great word

cheers... guess it should be use'n't, as it's an abbreviation of "used not"
Perhaps it's spelled usedn't but just pronounced as above?

Didn't even notice that one slipping out, was underlined in red too
Hell, let's petition the Oxford, and have it put in.

During the last freeze I had to resort to dribbling water from a hot water line into my system to keep the tilapia alive. I expect some copper could have gotten into the system that way but I'll hope that it wasn't too much (not as if I was recirculating through it and my tap water is pretty high pH.)

I'm sure a domestic hot water heater could be retrofitted to be of some use to an AP system but I'm sure there are better choices of methods. The Hydronic heating for instance, running the hot water though "safe" pipes in the grow beds or even a coil in the fish tank or whatever.

Yeah with an instantaneous gas heater on it, so run the pump, heater instantly turns on, pipes get hot - to a heat specified by the thermostat... I'd put it in the sump though, as many heaters get really hot, then stay off for a bit then really hot again. It's possible you'll upset fish in the FT, and kill bacteria in the GB. plus in the sump, unlike the Gb you're certain it's covered in water, thereby ensuring the best conduction available.

I doubt you would scald fiah. They would stay away from a to hot heat exchanger. You have a thermostatic control on the hot water tank that could be set ay say 40 deg. C and another stat to control pump to heat exchanger that could be set at 30 deg. C.
I did a test run with an aluminum heat exchanger in the FT. The solar hot water collector was inside the green house glass. It did not get the FT warm enough so am moving the collector outside. The hot 50 gal. hot water tank I use is in the green house. I replaced the 240 volt element with 12 volt DC and dump- battery voltage to it when PV and wind genny have more than battery 14.2 volts. I have yet to finish the outside hot water collector install.

Now that I've gottin into completely, and bought a tank, here is what I've found. The tanks are glass lined (safe) The intake and outel appear to be stainless or coated steel (also safe), the dip tube that runs the cold water down to the bottom is plastic (safe). The drain fitting and pressure overflow fitting are brass (undetermined). In other posts, plumbers have commented that its a treated bass, designed not to react with the water. Also the Anode, which used to be zinc years ago, is magnesium (also safe in small dosses).

I'm going to run it as is, fill the system with water, run it 2-3 days, purge the system, refill it, run it a week. Then I'll test the system water and the tap water as the control and see if anything is out of whack.

Sounding better... and sounds like a good plan.... let us know the results please

TCL, all the modern USA water heaters I have cut in to have been completely steel. Not even galvanized only coated with a glass or enamel inside. That's why when there is a defect the rust through and spring a leak.