Light Leaks in the Reservoir

[golfnrl]

I have two 12 gallon reservoirs. Each has a lid with one hole in it for access for the plug of a circulation pump and the leads for the PH controller. So far so good. But I've read about light leakage into the rez and how it promotes unwanted growth, which clogs up the filter, and stench. I've experienced both. I'm looking for a better way to plug that hole. Right now I use a rag but I don't like it. I was thinking about some kind of shapable compound. I'm old so I thought of silly putty. It's moldable but I don't know if it would bind to the plastic lid and the cables for the equipment. And, I wonder if it might be toxic for the plants. Google says it's still available online. Anybody have any suggestions? What do you use?

[Ckbrew]

Get a tube that is solid black, the one u have there is letting in light no matter how u seal the hole. There are multiple wires and tube running through there, so probably something custom will have to be fabricated. Perhaps a lab stopper with holes drilled in it. I can't see the mechanism that is feeding the pH down to the solution, but you are setting yourself up for a failure. Having that much adjustment fluid above the res sets up a possible siphon in the event of a pump failure. Change the height of the bottle to be the same as the res. Also consider a smaller bottle of solution. If a failure does occur a smaller volume will limit the damage. I guess what I am saying is that I see a Murphy failure chain being formed. Murphy will kick u when u are down.

[golfnrl]

My original post wasn't very clear. I grow with the autopot system. It's a gravity fed wicking type of watering system, so no water pumps. To get head pressure the rez is elevated about 12" off the floor. The clear tube in the pic is the discharge line from the PH controller. It stays well above the water line and drips into the rez. The PH solution has to go through the controller, so no siphoning issues. IDK what a lab stopper is but imma check it out. I've looked for rubber grommets/stoppers at the big box stores and haven't found one, yet. I'm not sure the clear tube can be replaced but I'll check it out for sure. I understand about how that tube can let light in, but my keen sense for the obvious failed me this time. Thx for the help and guidance.

[DW2]

Howdy golfnrl, exactly what Ckbrew said, get rid of the clear tubing! As for the holes into the reservoir, you can get rubber grommets at just about any home improvement store or online. Just get them with the inside diameter to match the outside diameter of the tubing (or cord, if going to a water pump) and drill a hole in the reservoir to match the grove diameter of the grommet (that size should be labeled on the package of the grommets). This will provide you with an air and watertight seal. I also cover the pebbles in the net pots to prevent any light intrusions as well.

[3Berries]

You could use PVC conduit fittings and cable glands

[golfnrl]

I learn something every day @3Berries...If I ever knew what a cable gland was I've forgotten. The google machine has shown me a there's a whole cable gland world out there that I didn't know existed. That may be the ticket.

[3Berries]

I was an electrician in a wet and acid industrial environment. Found out what worked and what didn't as far as sealing and protection. Beware nylon and acid.