Howdy, Folks! I’m hoping for some assistance with a problem I inherited. An old USDA greenhouse was renovated per standard government contracting rules (cheapest bid wins the contract). The pandemic slowed things down a lot, but the greenhouse renovation was completed early 2023. I won’t mince words; it’s a complete SNAFU of a greenhouse (panels falling, screws rattling loose, concrete cracking, bay doors stopped working, the list goes on…). The contractor (and his subs) had never built a greenhouse before, and it shows. We have been using the greenhouse since 2023 and dealing with various issues as they arise. The current most pressing issue is the PEX irrigation water line is exposed throughout the greenhouse that promotes algal growth and is slowly breaking down due to its continuous exposure to sun (it’s a frigging greenhouse! Sheesh, people!). We have a Netafim VibroNet system that is constantly being clogged with algae. The questions I have are 1. Is it worth treating the algae with UV or chemicals (recommendations would be great!) and, 2. How long do y’all reckon I have before I will have to replace the PEX with PVC? TIA.
by DrHortDork
4 Comments
For now, get some UV rated spray paint and get those lines painted. When you replace them, use something UV rated, or plan on painting the PVC if you use that.
Go buy some Drytec calcium hypochlorite (68%+) and run it at 3 grams per 50 gallons of water. That will give you ~5 ppm chlorine and should knock it back.
Can you put aluminum tape over it to finish the season?
Or some panda film around it and stapled to itself?
Do you have a spot to flush the lines at the end of your irrigation runs? I’ll put a picture example of this in another comment, but this comment is now too long to add a picture.
As far as changing it out from pex to pvc, do it as soon as possible. End of season at the absolute latest. If you want me to make you a shopping list and some instructional videos for irrigation, I can do that. I worked on commercial ag irrigation for a few years after covid slowed farmer’s markets, in massive nurseries that sold to Home Depot/Lowe’s/Walmart, in hemp greenhouses with overhead sprinkler systems, mushroom greenhouses with positive air pressure mist humidification systems. I’m sure you can put it together yourself if you understand how glue works, it’s *that* simple.
I also build ppm/mol charts and can help you make custom fertilizer blends tailored to your tap water.
I’d paint the clear pex with some sort of uv resistant paint or wrap in reflective tape. Obv flush lines fully but that’s where I’d start.
Can you add a UV sterilizer to the line.