I have been struggling with getting a good seal on the drain holes in my grow beds, which are one 55 gallon plastic barrel split and opened up clamshell. I'm trying to set up a bell siphon so I drilled holes in the bottom (was the side so it is curved) of the beds.
1st attempt we used bulkhead fittings which cracked due to over tightening, but they were not sealing properly, I'm guessing due to the slight curvature of the barrel.
2nd attempt was successful but we used 1'' threaded brass nipples, which I am now realizing are not good to have in an aquaponics system. My question is what is the hazard of having brass in an aquaponics system and what other options for this setup would work?
Should I order uniseals or were bulkhead fittings the way to go?
I would say uniseals, they are cheaper and far more likely to seal properly. what size holes did you drill?
brass contains copper and over time and in an acidic environment may corrode and leach copper into the water which can be bad for the fish if it builds up enough. What kind of fish are you growing? If you can keep the pH near neutral (7) you might slow the leaching.
Also over time as it corrodes it could start leaking.
a 1 1/4" hole (provided you didn't melt it too much bigger) will work with either 1/2" or 3/4" uniseals so if you were to order some uniseals then you could probably swap when you get them, just unscrew the current fitting and then pop the uniseal into the hole and use some slimy water to lube the pipe and push it in. It is usually fairly easy to push 1/2" or 3/4" pipe through a uniseal through a barrel. It is the larger uniseals that are often more difficult.
A must read,http://en.wikipedia.org/wiki/Brass
Brass can contain: copper, zinc, aluminum, lead etc ......this could be very bad for an recirculating system, since these metals are just increasing there concentrations over time in the system and plants may absorb some of it and it could end up in your stomach.