tub choices for bubbleponics

im looking to start a grow so my old lady will stop wasting money im gonna build something like the bubbleponics thing but im thinking of using a wide tub but a little bit shallow so that th plants can get more space.

any concerns i should be having?
the pic is an example only ill probably be looking for something a little bigger i just don't want to waste nuets using too much water. i could use a 35 gallon sterolite tub 27x17x17 but that's alot of water
altho now that i think about my big tub could be perfect. fill up the tub 1/4 of the way so the roots can dangle. maybe preventing root rot. and if somin dies easier to remove. maybe the roots don't get tangled. but im no way a grower yet. so i don't know how my hypnosis is true or not.
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on a side note this forum sucks in the function dept took forever to see how to add a pic .with the [/image] tag i could have placed the pic where i wanted it.

As far as a tub goes or active resevoir ( as i like to refer) the dimensions are directly related to two things: growing area and number of plants. Also keep in mind the different stages of the plants life.

Typically you'd like to have AT LEAST 1sqft per plant (indica) and 3sqft (sativa) during its vegetative and flowering stages. That's my opinion. This is assuming an average without considering topping, lst, or ScrOG/SOG. Those things you have to accomadate for but in your case I wouldn't worry about it. If the plants are stationary and cannot be moved due to them being in a "bubbler" this a pretty good idea of how much space you want.

During the early stages of its life until the plant reaches it full height the plant will drink considerably less water while quickly drying your tank in it's later stages. You will find you will have to refill more often. A good final number for your plant (the the later part of its consumption) I would recommend 3 gals. per plant. I have gotten away with 6 plants in a 3 gallon container for the first 6 weeks of its life but unless you want to have to constantly refill and worry about nute concentration it's best to move them to 3 gals each for a full grown plant and anywhere from 1-3sqft+ spacing. Obviously, if your planning to grow more than 3-4 ft tall like a giant sativa then obviously more root space is needed.

When using a shallow tub, i ran a drip system until the roots were well in the water and then added a bubbler until i was comfortable enough to remove the top feed system. Should work with or without a shallow tub. Some people use sprayers but I find my way a bit easier for me.

I would go for a height of AT LEAST 12". Depending on the height of your cups because you dont want them sitting in the water. The taller the resevoir the better. And at that length and width I would do two full grown plants (1.5 sqft each) ... so at least a 12 gallon container (half full of water the other half to let your cups hang. I'm not saying you cant get away doing more plants in a sea of green or something like that but for just a basic grow that's my suggestion.

Remember to only feed nutrients at the beginning of the week and to add just ph'd water to keep the resevoir full. Id put a fill line somewhere on your system to know how much water you have... maybe build a smaller tank until your are ready to transplant them to there final homes. Remember it all really depends on how many plants and how you are prepared to grow them and what you feel comfortable with. Wanted to help and put in my 2cents.

I'd like to piggyback on what Redaaron said because its a good point.

Considerations and Ultimately Efficiency: That type of system is good as a first choice, and I have an answer as to what I would do after reviewing several options based on some principles in Hydro that are directly related; (given you got your basics like medium, nutrients, ph, oxygen, and engineering) Depth, Volume, Energy, Time, and Space. Your most important variable is what kind of yield strategy your going for and how efficient are you going to be with what you got to work with.

Depth: If your growing in shallower water (6 inches of water), it will be much easier to produce more active, oxygenated, and turbulent water with less energy (aeration devices). With shallower depths however your vertical grow height will be affected but you can pack more plants in a given space, and by doing this you are shortening your vegetative growth period saving time. Also less energy is needed for light to penetrate the canopy of shorter plants. The depth and the volume of water is not related unless you consider space as a variable. A cubic foot of water is 62.4 pounds, so a 5' by 5' space would weigh about 800 pounds.

Energy: Light allows your plant to grow faster, and the amount of space you give your plants horizontally will affect their ability to absorb light, as will the intensity of the light and number of light sources. This is pretty even-steven; simply put you can stack them closer with brighter lights or more of them. Energy as light will bottleneck in many ways. Distance from light, number of light sources, cooling for air and water, nutrient uptake, oxygen required for faster nutrient uptake, and time spent mixing nutes or balancing phe. What it comes down to is efficiency.

Time: One of the best parts of hydro, especially bubbleponics, is the lack of time required to maintain the system. Also time can be saved by actually growing the plant faster with more resources which requires more energy; more airpumps, stronger lights, both of which affect water temperate and air temperature needing more cooling. Time is affected by volume because more water cuts down on ph monitoring, nutrient mixing, and maintaining your water level. Energy is affected by time because you can automate or make features of the system active to reduce trips even further.

Volume: If you have more water you have more buffering for ph fluctuations depending on type of nutrients, and your nutrients will last as long as they are available. In other words you want to maintain certain ppm of nutrients and plants will uptake them as they require, but in general the larger the volume of your system the more nutes you can add (good thing) which saves time but costs more per mix. Volume also allows more depth for bigger plants in a given space but this requires more energy in lighting to penetrate the canopy, oxygenate that much more water, and time in vegetative growth to get that extra height utilized.

So If large bodies of water make you nervous, I would have a backup plan like an emergency pump, build it on top of a pond liner that goes up the wall 1 foot and secured, or have some idea of where this water could possibly run off to with a worst case scenario. Water is heavy and dangerous but if you plan and do the calculations for load, and keep electrical devices and outlets away or high up, it is quite safe.

Your container will weigh 280 pounds filled to the brim, however it will be realistically closer to 250 pounds as the water level will be below the brim, more so later in the process... This seems like a lot of weight but with a quick siphon or a water pump and an escape route for water; this container can be light enough to pick up with 1 hand and move in just a couple of minutes, nothing is static.

My Suggestion: Use at least 12" for depth, go as big as you can in the space, and plan your square footage around the size of your plants' optimal harvest conditions. The beauty is these systems can be independent and simply replicated as long as you got the basic concept. You can just build more if you ever need to expand, and this takes away limitations in prefab active-design.

Your system if replicated would allow for different nutrient mixes in different containers. If it were me I would use 2 containers instead of 1 even though it cuts into your time. I would experiment with oxygen and nutrients, but don't overkill. If the bottle says add this much, add half of that in the first few weeks, and add just a tiny bit more to the second container. Increase this keeping proportions slowly (its easy to overfertilize), you'll see any signs of danger on container 2 creating a clearer threshold and a safety margin while maximizing nutrients but as a rule of thumb I personally always go with less than is recommended on the bottle; at max 75% recommended dose but start with way less like 1/2.

Be on top of PH at all times, and go heavy on oxygenation and light on nutes.

Don't reinvent the wheel, but every custom system is different with every strain. I've had people tell me to do things a certain way only to be suprised by my results. By this way you gain experience with strains in different conditions, and you save time and energy and become more efficient.

Good Luck.:thumbsup:

Don't think he even read the response I posted....