pvc piping?
 

Great site, thanks for keeping it up and the time spent, lots of good info. here.

What are your thoughts on an all HDPE (high-density polyethylene) piping system instead of PVC?

I don't think it would make a difference, from what I've read the HDPE isn't as strong, but for hydroponics systems, we're not dealing with large amounts of pressure.....

what is your concern vs the two choices?

Polyvinyl chloride - Wikipedia, the free encyclopedia
You might want to skip down to the health and safety section and come to your own conclusions.

It looks like Polypropylene would be an even a better choice that Polyethylene from a health point of view.

"Polypropylene (PP) is a robust plastic that is heat resistant, considered highly safe for human use. Due to its high heat tolerance, Polypropylene is unlikely to leach even when exposed to warm or hot water. This plastic is approved by the FDA for use with food and beverage storage. Polypropylene plastics can be re-used safely and with hot beverages."

Anyway, I'm just getting started in this hydro thing and don't feel like taking a chance on any plastics leaching into my organic and/or heirloom tomatoes.:)
Thanks for the reply.

good point, I would just stick with what we know works now, and let others experiment with their crops... :)

Is the Polypropylene a lot more expensive?

I have made 8 units all 24” x 16” x 8-3/4” rubber made toot containers.

2 of them have 2 pots each of 8” dia for a total of 4 – 8” pots – 2 types tomatoes.

2 of them have 2 pots each of 6” dia for a total of 4 – 6” pots – 2 brussel sprouts and 2 eggplants.

The above will all be on a 5 gallon pail with higher nitrogen and ph.

The next collection is 4 toots. 2 with 6 – 4” pots for 12 types of herbs
and 2 with 3 - 6” pots for cayenne peppers.

The same all 4 on a 5 gallon pail but lower nutrient and ph.

The whole system is bassed on pex pipe or HDPE – the white flexible pipe for water distribution in most homes theses days. I find the plastic pex – barbed fittings work well – I do not put a crimp ring on any of the pipe that is submerged in solution, instead I use the orange Teflon tape and wrap the fitting a few times to form a gasket. It is handy to use on pumps with a ¾” fip x ½” barbed fitting because the ¾” pex is 1/2 “ on the inside and fits the pump like a glove. The pvc that is used for venting furnaces and water heaters is much thicker – ¼” and in my books that makes it subject to a tap and die set. Threading this pipe is very easy and will make a professional looking job…

oh and I will be adding 2 - 300 watt photo electric panels to an inverter with 2 deep cycle batteries to avoid the use of extension cords.

I can’t wait to plant this out side.

Hope you do not mind a little ramble…

PVC is the industry standard for water piping, even for your drinking water. There is also high temp PVC for hot water apps. It's very difficult, at least in my experience, to find HDPE piping. I haven't heard too much concern about leaching in PVC, mostly about how nasty the stuff is to manufacture.

If you are worried about strength either get a thicker pipe or there is also ultra high density polyethylene, but for piping its probably rare or cost prohibitive.