I've read through the thread and I think your decision to go with fewer plants is the right move.
Two key points about water temperature - at 64°, phosphorus uptake starts to roll off. Dissolved oxygen levels do tend to increase as temperature drops but I would not run a hydro grow at 64°. One issue is that it's not going to be 64°. It's going to be
about 64° and, since P uptake rolls off
at 64 and
the level of DO is only slightly higher at 64 than at a slightly higher, safer temperature there's little benefit yet there can be a signficant negative impact to water that cold. I've grown at 68° for years without issue and have had excellent results.
A water chiller does throw off some heat—it is an electrical device that reduces the temperature of water and that energy has to go somewhere, right? If heat is an issue, move the chiller to another location, and drop in a submersible pump. The hoses to my chiller are 15' or so.
The difference between an Active Aqua chiller, for example, at $400 and less expensive chillers might be because Active Aqua uses a titanium core in their chillers. My chiller has been in use to four years and has worked flawlessly.
Re. the number plants is an issue. The key to yield is not the number of plants. The key to yield is how many mols of light the plant/plants over the lifetime of the grow. The formula for yield is based on moles of per square meter of canopy. More light ≈ more weed.
Something's got to catch all of those photons and that's where the idea of "more plants" comes in. But it's not more plants, per se, it's the larger canopy area that's the key. If you grow one large plant vs multiple small plants, the yield is very similar. The biggest issue is to generate lots of light and make sure that you have lots of canopy to catch all of those photons.
Confirm that
this is the system that you're using?
If that's the case, I would grow one plant. It's only an 8 gallon bucket so the actual volume of nutrient liquid is about 6 gallons I would estimate. As you've demonstrated, a reservoir that size cannot support five plants.
A "5 gallon bucket" holds about four gallons and you can get a nice crop from one plant in a 5 gallon bucket. As a point of reference, I grow in a "35 gallon" reservoir which holds 28 gallons of nutrients and, historically, I've grown one plant.
My current growy current grow is two plants and I should have stuck with just one.
Not many growers use a "35 gallon" res but my grow
is a DWC setup with a water chiller so the information and the lessons learned at the grow journal links in my signature block might be helpful.
good morning Amigo.
