Trouble with Bulkhead Union for Hydroponics

Hi there,

I am currently building a Automated Hydroponic System largely based on the one on your website. I have all of the materials and I am now starting to build and assemble everything. As for the water collection aspect of things I went with 4 inch schedule 40 PVC rather than the sewer and drain pipe that is documented in the materials list because it is food safe. This poses a bit of a problem when trying to attach the bulkhead union to the bottom of the pipe as the PVC is significantly thicker than sewer and drain piping. I tried heating it with a heat gun to get it to form a better seal but it still leaks even with a rubber gasket between the bulkhead and PVC.

This 4 inch schedule 40 PVC is quite expensive and I would like to preserve what I have bought. I decided to buy some waterproof food safe aquarium silicon to try and seal the bulkhead and will be giving that a try shortly. Has anyone else had a similar issue with this? Any suggestions or thoughts would be appreciated!


I really wish Kyle would put some kind of disclaimer at the beginning of that video telling people that there are much better designs for a beginner hydroponics system :frowning:

Forget about the trough design altogether and just use a simple flood tray and put the plant pots in the flood tray. You can make a flood tray out of any plastic storage bin. The shallow storage bins that fit under beds work well as flood trays for 3 to 8 inch pots. That trough design in the video is just to display the overall concept of the automation. Trough systems are not really the most efficient design for a hydroponics system. Trough systems are complicated, hard to clean, prone to leaks, and limited to the types and size of plants you can grow in them. It’s also difficult to remove the plants from them for inspection and pruning because all the roots end up getting tangled together in the trough. A simple flood tray system is easy to clean and maintain, and is easily adaptable to a wider variety of plant types and sizes.

This flood tray was made from an inexpensive storage bin available at any home-goods store, I strategically placed the auto-siphon drain where it would not be in the way of 6 or 8 inch pots when the tray was full of pots, and also where it would drain straight into the nutrient reservoir underneath the tray.

That’s a really interesting setup. If I weren’t so far into the project already I could pivot but I’ve dug myself a hole at this point. :rofl: For what I want to plant the NFT system in the video will work well and I’ve even been able to expand it to 36 planting holes instead of the 17 in the video in the same grow tent footprint.

I will also be able to stack new rows on top if I want. I do like the flood tray design for plants that would need soil like bulbs and root vegetables though and I think I could incorporate that into my design so it is above the NFT system. I’m guessing you just use LECA for the planting material?

Yes, I’m using leca or “Hydroton”. I’ve been using it for years to grow everything from tomatoes to string beans, to basil and all sorts of other vegetables and salad greens, and now I am using it to grow and breed cannabis. I’ve used hydroton in different system types from tower systems to ebb & flow trays, flood and drain trays, and right now I have my system setup with a couple of Dutch buckets.

In fact, I’ve been re-using the same 20 pound bag of hydroton for the past 6 or 7 years now. It gives the same root and plant support as soil, but in reality what is happening in the root zone with hydroton is the same thing as NFT. The nutrient film is just on the clay pelts instead of on the bottom of a trough… a trough doesn’t have root support like hydroton :wink: Hydroton also gives much more O2 exposure to roots than a trough.

I like to have a system that is somewhat modular so I can change things up and adapt or experiment as I want without having to redesign the entire system. I also use recycled and re-purposed items as much as possible to keep costs to a minimum. My Dutch buckets are 100% homemade from re-purposed laundry detergent buckets and a couple of cheap 3 gallon garden pots. My 4 gallon humidifier is also made from a laundry detergent bucket.

When this system first started out, it was a 2-tier setup with one flood tray stacked above the other, and they were watered in cascade, I only needed to pump water up to the top tray and flood it, and then the auto-siphon takes over and the next tray fills and so on. The auto siphons also completely drain the flood trays to reduce algae growth. Have you thought about how you are going to take apart your trough system every month to clean the algae out of it? Seriously, if this is your first hydroponics system, go with a simpler design. If you are just growing salad greens, you can go even simpler and use a DWC or raft type system.

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