Reservoir size?

Planning a grow and wondering what size my reservoir should be to accommodate about 10 plants

What type of system are you running? Usually the bigger the better (within reason). A bigger rez will allow things to stay stable much longer. If its to small you will be adding back all the time, ph & ec will be a bitch to maintain. You will have to get a few runs under your belt, but the goal is to have the rez large enough that the plants are using up nutes at the same rate they use water. This will also be dependent on your mix and what stage of growth your at. No magic formula, you just have to get through a few grows to figure it out for your set up.

30-50 gallons. bigger is easier.

i use 27 gallon yellow top things from home depot for each 2x4 ebb tray. I have to top off at least once a week in heavy bloom but since im in there every day i usually top it off a couple times.

The size of your plants will be needed to answer this question. big diff between 1 footers and 5 footers when it come to rez size

I uesd a 60L rez for 3-5, 4 foot plants and it was good for a week

Thank you guys, this is great news, I thought I'd have to get something way bigger and I was worried. I'm planning on following Al B. grow format which uses a flood system, although I'm still unfamiliar with all the different types of hydro systems. I'd be open to any suggestions and advice for systems doing the two week harvest schedule with sea of green.

This has nothing to do with rez size, but if you plan on fallowing Al's system, the first thing you want to do is perfect your cloning skills.

what is to perfect?easiest thing about growing is cloning. cut em, put em in cloner with tap water, leave alone. done.

I use 200 Liter res for 800watt flood tables it seems just right, I could easily go with 1/2 the res size if I wanted. I tried various hydro systems, number 1 for me is flood and drain, I only switch my table to a DWC in mid winter because it is easier for me to add a 200w res heater instead of 2kw space heater.

Skittlesmcp said:

Thank you guys, this is great news, I thought I'd have to get something way bigger and I was worried. I'm planning on following Al B. grow format which uses a flood system, although I'm still unfamiliar with all the different types of hydro systems. I'd be open to any suggestions and advice for systems doing the two week harvest schedule with sea of green.

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for flood/drain, you have a lot of water moving between the trays and res. with NFT, drip, aero, the amount of rapid volume change in your res is minimal. with DWC, there is no rapid volume change: the bucket is the res itself or the buckets recirculate with a central res. point is, the res volume doesn't need to change much in order for the system to operate. with flood and drain, your res volume changes constantly. of course plants drink water and that changes water levels, but that's not what i'm talking about. i'm talking about the system itself moving a large volume of water back and forth.

it may seem like i'm making this way more complicated than it needs to be, but it's not as straightforward as you think. mistakes can cost money, time, and frustration. the shape and configuration of your res, pump, and drain have a lot to do with how much water you'll need.

1. your res volume is going to be at least difference between the volume of your trays flooded and when they're drained. i used to have a hybrid setup that flooded/drained only halfway, so the bottom half worked like DWC. in such a case, you're only calculating the difference between flooded and drained. my 2'x4'x6" trays hold about 10-11 gallons each when they're flooded to the level i have them set at (judging by the rough volume markings on the tray itself). there's probably less than a gallon left in the tray when drained, so let's call it 10 gallons. you'll probably need something equivalent to one 2x4' tray, right? maybe two trays if you're vegging longer? let's say two, so 2 x 10 gallons = 20 gallons, just to fill the trays.

2. figure out how high the top of your inlet is on your water pump. probably a few inches from the bottom of the res. this is the minimum water level while the flood tray is fully flooded. any less water and the pump will go dry. if you put in a float valve to auto-topoff to res, then adjust the float so that it starts to fill an inch before it gets down to this minimum level. one way to figure it out is the just set the pump in the res and start pouring water in 1 gallon (or 5 gallons) at a time. when you've covered all of the inlet port on the water pump, you're there. the taller and narrower your res is, the less "dead space" you'll have under the pump inlet. the shorter and wider your res is, the more dead space you'll have under the pump inlet.

3. if you're using an auto/bell siphon, figure out how low your drain from the flood tray(s) will dip into your res. this is the maximum water level while the flood tray is fully drained. any more water and the drain may not function properly without a "carb" to let trapped air out (which ends up working as a venturi once the siphon gets going). submerging the drain muffles the toilet flushing sound at the end of the drain, but can be tricky to tune. if you're not using any kind of siphoning action to drain the tray, the top of your res is pretty much your max water level. doesn't matter if the drain outlet is underwater. shoot for at least an an inch or two below your maximum water level. if you want, you can add an overflow port (or better yet, two or more of them) at the maximum water level to prevent the water level from getting any higher.

4. it's likely that you're not going to fully drain your res completely dry since the drain isn't going to be at the very, very bottom (unless you have the res elevated and the drain underneath or you vacuum it dry every time). fill your res enough to cover the drain inlet, then drain it. use an empty wetvac to vacuum out the rest. the volume you suck out is your "dead space" that will never get drained passively. if you plan on draining your res almost completely each time, then no need to calculate dead space.

5. eventually figure out how much your plants will drink a day. if you're doing perpetual harvest, your water uptake should be fairly consistent day-to-day or week-to-week. varying maturity of plants with perpetual harvest keeps things fairly stable. if you're growing an entire crop on the same schedule, water uptake change rapidly as the plants go through different phases. i've seen large sativas suck up as much as 3 or 4 gallons/plant/day in DWC, as much as 2 or 3 gallons/plant/day in flood/drain. adjust the numbers accordingly based on strain, veg size, etc. since you're probably going to run smaller plant sizes, count on maybe a max of 2 gallons/plant/day when the plants are peaking? seedlings and clones probably suck up close to zero for our intents and purposes here, so by taking the median, you end up with a rough average of what your plants are drinking daily. in your example, if we use 2 gallons/plant/day * 10 plants / 2 = 10 gallons/day.

Say you want the system to run without topping off or doing a res change for 7 days. 7 days * 10 gallons/day = 70 gallons. lets say on top of that, you're running two 2x4' trays that hold 10 gallons each. now you're up to at least 90 gallons, and that's not even calculating any dead space.

so to answer your question:

MIN = minimum volume of res
TRAY = volume of trays full
DEAD = volume of dead space needed to be filled in order to operate the pump
DAILY = volume drunk by plants/day
DAYS = number of days you want to go without topping off or doing a res change

MIN = TRAY + DEAD + (DAILY * DAYS)

you'll want to select a res size that can accommodate at least this much water. as far as max res size, bigger is more stable, but there's more water/nutes/work/pollution when you do res changes. you'll also need more H2O2 and/or bennies with a larger res volume. bigger res also means a bigger footprint and/or less vertical clearance for plants/lights.

consider a split res that auto-topsoff (autofills). the res under the trays only needs to support the pump and accommodate the volume of the trays. so 20 gallons plus another 10 gallons dead space, let's say, total 30 gallons. the total you'll need to make up for plant uptake and evaporation for one week is 70 gallons. would you rather have a 100gallon res crammed in under your trays or would your rather have a modest 30 gallon res under the trays that are automatically topped off by a 55-gallon garbage can that is located away from the trays, lights, etc? you can always start with one garbage can and add on another one if you need more water to make it through the week.

A good rule of thumb is 3 gallons for every 3 foot plant. So, if you grow 10 3 foot plants you'll need 30 gallons. 10 4 footers = 40 gallons.

Thank you all of you guys, I get great advice and info from everyone and I'm starting to piece together what my setup will look like. Haole420 thanks so much for the info, helped a lot with the planning for my setup. Keep the posts comin guys, my brain is like a dry sponge and all it wants is those juicy grow tips

I picked the tote that was on sale and could hold a 100 liters without bowing out. lol. $15 and it worked! lol

superstoner1 said:

what is to perfect?easiest thing about growing is cloning. cut em, put em in cloner with tap water, leave alone. done.

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Well I'm glad its that easy for you. But most ppl dont find it that easy. And if hes doing large clones like Al, he would also have to learn proper mother maintenance. I told him this because from the sounds of it he may be a beginner. We cant all be pros like you, and its a big task taking on a perpetual garden. I think its a mistake to make cloning sound to easy. If it where,dont think we would see so many post on this site about cloning problems.

Skittlesmcp said:

Thank you guys, this is great news, I thought I'd have to get something way bigger and I was worried. I'm planning on following Al B. grow format which uses a flood system, although I'm still unfamiliar with all the different types of hydro systems. I'd be open to any suggestions and advice for systems doing the two week harvest schedule with sea of green.

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a wilma system will be good for you. http://www.hydroponics-hydroponics.com/pd-atami-9-pot-wilma-system.cfm

you can get different size ones,like 4 pot,10 pot,16 pot etc.they are very simple to set up and use.you dont need to use all the pots,just as many as you want.

[video=youtube;fjY3N6WmMmE]http://www.youtube.com/watch?v=fjY3N6WmMmE[/video]

Reservoir 1 was built in 1950 by the city of Findlay as a municipal water supply.

mountainboy said:

Well I'm glad its that easy for you. But most ppl dont find it that easy. And if hes doing large clones like Al, he would also have to learn proper mother maintenance. I told him this because from the sounds of it he may be a beginner. We cant all be pros like you, and its a big task taking on a perpetual garden. I think its a mistake to make cloning sound to easy. If it where,dont think we would see so many post on this site about cloning problems.

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Maybe it's just hard for you inbreds with no branches on the family tree. I take large clones and I have no mother plants. Why is it a mistake ? It is the most simple part of growing. Even when I was a noob it was the easiest and still is.

I would think as well as some skill in cloning, maintaining a mother would be a bit of a hassle. I have never kept a mother myself but partner had 5 blueberry mothers that were 4 years old before they finally lost vigour. I have cloned a few plants and the rooting part I do find fairly straight forward but the plants always seem to be kinda runty compared to seed stock. But i really am a newb and on my 4th hydro grow. Back to the thread lol My res as said was 100 L and did not do any math at all, just got extremely lucky!! Barring the issues I have with water quality I leave my res for 6-7 days without touching it except to add PH down constantly lol. My first grow was so far the best with the 6 plants getting huge at about 6 feet tall and I still only changed res every 6 days. Mind you the water level was getting real close to the pump inlet. Not sure if it was an overly robust strain or I just got lucky, but I did monitor water and again only adjusted PH to around 5.8ish.