Backyard Aquaponics
A place to discuss aquaponics

Or you could add some extra "tees" and span the frames horizontally to add some rigidity

I used PVC because I aint the welding type. Coulda used wood, but PVC is light and fairly cheap.



I have no idea what k rails are. Is it like reo?



Because of the curvature of the roof, even if it sags between the spans the water should still run, so I don't think I'll get pooling problems. By putting horizontal connectors between the spans it would provide a great spot for pooling. If you're talking about lengthwise support, I suppose that'd help with rigidity, although I'm fine with it bending like the blazes in the wind, so long as it bounces back.

Hey does anyone know where the discussion on PVC and greenhouse film was? I can't find it. I seem to remember it saying something about it reducing the life of the film.

Hi gemmell
The film i bought recently gave me this information:
Polythene is essentially a hydrocarbon chemical compound and frequent applications of similar chemicals containing the same elements, which many agrochemicals do, will be absorbed by the film and will act as a solvent - de-activating the UV stabiliser and causing the film to degrade before its design life. The two specific chemicals that have this affect are sulphur and chlorine. Do not use chemicals that include these elements. If this is not possible wash the polythene with clean water after contact with any chemical.

PVC (poly vinyl chloride) polymer is 56.8% chlorine by mass, so its best to cover it up

I bought some tape from the film ppl, one side has a type of woolen fabric on it which allows the film to slide easily and thus protects it from rubbing...the tape is 40mm wide and just stuck it to the edges of the GH...I used steel pipes in my GH but the tape should stick onto pvc too

Thanks hex/lkb, very informative.

I'll get some of this self adhesive tape. It's just self adhesive felt...

.



I have no idea what k rails are. Is it like reo?

K rail is like Hi top only smaller, this is the thin metal lengths that get put between fence posts so you can tek screw the tin on to your fence.
I will try and take a pic for you tomorrow, it's raining hard here at the moment so don't wanna go outside

Looks like its called Polyguard Tape down your way
This is the stuff,
http://www.redpathaghort.com/accessorie ... ality.html

That be the stuff Hex, thanks

OBO, will look forward to the pic, I've still no idea what it is.


Hex/LKB, thanks, that was the stuff I "ordered" (asked if they could chuck some in with my greenhouse film if they haven't shipped it already). If they don't, I can get it through my local hydroponics store, though they'll just order it from redpath and charge me freight + their cut. Roughly $40 for a 50m roll (which still seams reasonable).

In other news, it's still frighteningly cold around here. The max's are still 11s and 12s and the mins -2s and 0s. However the introduction of the 300watt heater seems to be able to increase the temps of the water during the day up to around 8.

Measurements:
Ammonia 0
Nitrite didn't measure
NItrate 10
Ph 6.8
Hardness 200 (which is a little bit of a worry...)
Salinity 5ppt - the strawbs are a bit rough around the edges.

Happy about the Ammonia / Nitrate though. Still, growth is really slow because it's cold, so the greenhouse is still going in.

Hi Gemmell
Shipping is the killer
Your tape prices seem very reasonable, 45m of 30mm wide cost £15 (excl shipping).. which works out to about $30 Aud. The hotspot tape i have is a closed cell white foam about 3mm thick with a very slick plastic top layer.
I searched high and low for "batton tape" which sounds similar to your felt tape except its sticky on both sides.. it doesn`t exist over here.

-2c is a tad nippy for fitting greenhouse poly, try to pick a sunny day or it`ll be as saggy as a sock when it warms up

gday gemmell. Ur on the money with the salt/strawberries. At this time of year and with these temps a water change won't boost things much anywho imo.
Harder water is better than softer as i am sure u know. Growth will pick up in a few weeks i am sure, at least it seems u have taken the edge off those cold lows so whilst ur fish may not be banging into the food, I am sure they will be a bit happier.

That be Gnash, not me lol

Heh! Giddamn, You Kalgoorlians all look/sound/type the same to me.