Hey guys, just thought I’d throw my 2 cents in (I work for Netafim and deal with designing high end large commercial irrigation systems for both traditional Ag/greenhouse crops and cannabis).
The Octa-bubbler method is on its way out, it was a method that was born of necessity and of not having access to commercial irrigation equipment and designers, and is not used ANYWHERE else other than cannabis in commercial Ag or greenhouse facilities. It was a landscape irrigation product designed to give some water to some plants sometimes, it was never meant to be a precision hydroponics device. Uniformity just isn’t there, the plants at the front get different amounts of water than the back, and even compared to a neighboring plant on the next octa-bubbler over. Uniformity in water applied is VERY important in all cases. If a larger amount of water runs out of the bottom of one plant compared to another, that plant will consequently have a lower substrate EC and higher water content, which steers the plant towards vegetative growth, and will negatively affect flower production compared to the plant that had less runoff (unless the runoff is good at the larger amount, which means the plant with less runoff will likely hit buildup toxicity).
We just switched over the Jungle Boys, who were one of the first to make the octa-bubbler method popular, and I’ve done a LOT of switching out octa-bubbler setups for low volume drip systems over the past year or so, with phenomenal results in every case. In general, its good to remember: if a product doesn’t exist outside of cannabis and it’s meant for managing root zone environment (irrigation, fertilizer additives, substrates, containers, etc) be very wary of it and make sure you have a thourough vetting process to evaluate it. There are a lot of people/companies out there that will relabel and sell a product never meant for crop production into cannabis just because they can, and they make a lot of money doing so. Doing an Octa-bubbler setup with floraflex caps will cost you upwards of $10 per plant site, where a commercial quality drip system will cost you less than 50 cents per plant site and will give better results (Netafim sells at the same price to everyone, whether you grow cannabis or cucumbers).
The rule of thumb to remember with hydroponic substrates (coco, rockwool, sphagnum peat, etc) is to keep the flow rate per drip site below 1.5 L/H (0.4 GPH). Anything higher, and you are guaranteed to see channeling and uneven wetting of the substrate. Octa-bubblers can only go down to 8 L/H (2 GPH) per spigot, which is 6X too high, and their pressure regulating feature is not very accurate to begin with.
Another good rule of thumb for anything other than rockwool is to have a low flow drip site 8 inches in all directions of the container (rounding down) for maximum distribution uniformity. For example, a typical 1 gal pot would have one drip stake, 3 gal would have 2, 5-7 gal 4 stakes, etc. Rockwool is simple: 4" cubes and under, 1 stake, 6" and big mama cubes 2 stakes, and 1 stake per plant in slabs, with a minimum of 3 stakes per slab (one in the middle if only 2 plants per slab).
Netafim and other dripper manufacturers make low flow rate drippers (although, even if I didn’t work for them, I’d still use Netafim just for the fact that they are the most precise and most clog resistant drippers available, and cost difference is negligible for anyone with less than 100,000 plants). Netafim has a 1.2 L/H drip stake assembly (PC dripper with check feature, length of 1/8" micro tubing, and stake) that works perfectly and can be used in any hydroponic substrate until you get to hydroton (expanded clay pebbles over 1/2" in diameter), at which point you’d use a PC spray stake instead.
As far as a pump goes, a simple $100 shurflo diaphragm pump with built-in pressure switch (they call them “demand style”) with a $60 pressure tank before your manifold of zone valves works great. Then you will always have the necessary pressure (between 12 and 50 psi for Netafim drippers, anywhere in between there they will put out exactly 1.2 L/H) and the pump will kick on automatically when it needs to repressurize. All you need is a simple cyclic timer like the $80 galcon that will let you set up a watering window during the day and turn on for X amount of time and off for Y amount of time for best results. Normal irrigation timers with only 3 or 4 start times per day won’t cut it for precision pulse irrigation (method with the best end results seen so far in all commercial crop production industries).
Hope that helps! Feel free to ask if anyone has any questions about the above.
Thanks for reading!