Backyard Aquaponics
A place to discuss aquaponics

The solar heating for our swimming pool [ newly installed due to storm damage] is governed via 2 sensors.

The first is the air temp and the second the water temp.

Could this same principal not be used to achieve temp control etc. when using a solar HW system to heat AP FTs?

Both sensors are controled by a temp setting gauge that can operate in a stand alone manner seperate from the salt water chlorinator.

The gauge ranges from 16c to 40c.

Vegieman - How much did the pool heater cost? I think that sounds like a chipper idea.

Here is my plan:
I am getting a 3000L joel tank. I'm going to coil black polypipe around the outside of it. Then I'm going to put some insulation over the top of that and finally some bamboo screening (to hide the insulation). With the black polypipe, I'm going to run it through a pump, and up to something like that B* solar collector we mentioned before. If I put alcohol or maybe just water with anti-freeze in it I should be able to use this system to control the temperatures pretty well - if the FT is too hot, run it at night, if the FT is too cold, run it during the day.

Because the water is not mixing in with the rest (it's just coiled around the tank) temperatures should change slowly (which is desired). The pipe full of water also acts as an insulator when the pump isn't on, any temperature loss (or gain) first occurs in the polypipe before it "seeps" through to the tank. The insulation is there so that instead of radiating whatever heat/cool outwards, it radiates it in towards the water.

What do you think? Crack pot? The other thing I can do is instead of putting the solar collector on the roof I can just put it on the slab of the carport. Kind of increases the available thermal mass.

Hrrm. I just did some quick calculations. On a 2.3m diameter tank, using 20mm polypipe, I'd need ~170m of polypipe to completely cover the tank. That's a hell of a lot of pipe. Maybe I could just do the bottom half. That's also an overestimate, because the TOP of the tank is 2.3m but I've no idea what the bottom is. But still.... that's a lot of pipe.

I think all up the repairs cost the NRMA around $3000 [with labor etc.] as for the sensor unit itself, I couldn't tell you but I am planning on contacting the guys again soon to see if they ever get any unwanted solar panels I can buy cheap and also suss out the sensor units too I will let you know when I contact them.


Would the water not help to insulate the temp better if you coiled on the inside of the FT? [ After ensuring no leaks to allow the anti-freeze etc. from contaminating the system]
You could initial 'Charge' the unit via the hot water tap into a pre-delivery 'Holding' resevoir to ensure a slow but steady increase in the water's temp. Just a thought is all


Only trouble with putting it on the floor is the space factor and the risk of accidental damages

Keep an eye out on good old eBay you never know what may become available

So I just spent $400 on plumbing stuff. $100 for a 6m length of 80mm pressure pipe.

I don't feel remorse - I am going to do this one PROPERLY. Last one was a bit... err... dodged up. Lost of risky things were used (like that blue 90mm PVC that's used underground). So this one, no DWV, just pressure pipe. A lot of it.

Might start a new thread about it someday.

I resurrected this system. Moved the remaining gold fish to a safe place:


Pulled out all my lovely growth:



Including some big rootballs:



I think this is the source of my woes, it looks a little more rusty than it did orginally...



For those that don't believe that scoria gets hot in the sun - check it - It seems my PVC pipe has almost burned.:


Redid the bathtubs with a layer of bubblewrap (for insulation) and then pond liner, stock with 50 trout and bobs your uncle, it's growing great guns. The following two photos were taken on 29/03/09 and 18/04/09 (3 weeks apart):

looking good Gemmell

hope to see some more pictures soon as your growth looks amazing

Here it is - taken 29/03/09, 18/04/09 and 25/04/09. so 4 weeks:




I've started trimming the water cress - I'm going to have to start mowing it soon....

Did a pH test today - 6

Yikes, added some Eco Rose to try and get it back up somewhere reasonable.

Plants and fish are growing great guns (photos taken 9/5 and 16/5 (one week of growth)):

How much did you add Simon... it's pretty powerful in terms of it's buffering ability...

Yeah, be super carefull - it all looks awesome - love the fish pic

Dang, I was not careful at all. In fact I forgot about it and didn't even measure the pH this morn. I just added quite a few shakes of the packet in there. You got some kind of indication on how much I should have used?

I thought it would buffer to pH 6.8 ish and then once it reached that it wouldn't affect anything until it dropped below that again.....

"Quite a few shakes"... isn't really a definitive answer Simon.....

I add about a 1/2 - 1tablespoon (max) in 1000L... and can see a pH change of about 0.2...

In a 3000L tank... a "few shakes" might be OK... "quite a few", may not be....

Remember the pH scale is logarythmic.... a change in value of 1 is in fact a change of 100 times...

Do a pH test please...

Well I measured my pH..... it's still 6.0

So I added a bit more of this stuff. Probably half a teaspoons worth. I'll measure tomorrow and repeat until it gets up to somewhere reasonable. Any idea how long it takes for it to take effect?

Less than 24 hours.....

A tablespoon in 3000L would probably move you about 0.1 ....