First time hydro, going to try Ebb/Flow - is this a reasonable plan?

Discussion in 'Hydroponics / Aeroponics' started by Larry3215, Feb 2, 2018.


    Larry3215 Well-Known Member

    Hello everyone! I am hoping to get some feedback on my first ever hydro plans. Im in the final weeks of my first MJ grow in soil and its going pretty well. I have decided that I want to try a hydro grow next time around.

    After tons of reading, I have decided to try an ebb/flow setup with two plants in scrog. My grow tent is roughly 7 sq ft (28”x38”x48”tall) and I have a 300 watts LED light fixture using 3500k Solstrips (the same led’s as in Quantum Boards).

    I have read a ton of threads and one common problem is heat in the rez from submersible water pumps. In order to reduce the heating problem, I am going to use an air driven water pump instead of a submersible, mechanical pump. I can mount the air pump remotely and cool it with a fan, so hopefully I wont have heat issues.

    Im going to have two interconnected 5 gal totes as grow buckets filled with hydroton. They will be connected in series with the water entering one and draining from the other one. The rez is going to be another 17 gal tote with at least 3 DIY air stones. It will be under the table the tent is sitting on.

    Im going to try Mega Crop for nutes.

    Attached is a rough sketch of the layout. I have done some ‘wet’ trial runs and it takes roughly 15 minutes to fill and about 1 minute to drain using the automatic siphon – no electrical timers needed. The air lift pump runs full time. As soon as the 5 gal totes get to the preset fill level, the siphon trips and drains back into the rez and the cycle starts all over. Those times are based on just water in the totes. I haven’t tested with them full of hydroton, so the final times may be a bit different, but I expect the same ratio of fill time to drain time. I can adjust the fill and drain times by tweaking the siphon and air lift pump rates, so there is some flexibility.

    Anyway, I love to get some feedback, advice, suggestions, criticisms, raspberries, etc. A lot of my reading and research has been on this forum, so I already owe you guys a bunch of thanks!

    hydro planlabeled.jpg
    OneHitDone and Gquebed like this.

    JSB99 Well-Known Member

    The following is just constructive criticism

    I would keep your first hydro grow much more simple, until you've gotten your hands wet (pun intended :p). Try something like a couple individual bubbling buckets at first. Very simple method with awesome results!

    It looks like you've put a lot of thought into your design. But here's the thing, you might be trying to reinvent the wheel. If you browse around, you may not see others using some of the concepts you've laid out. This may be because others have tried and didn't get the results they wanted. If you want to have the most success with your initial hydro grow, follow the standards that the experienced growers go by. If you find someone who's been growing for years with their hydro system, that's where you should be getting your ideas from.

    Hydro can be a finicky bitch, so I wouldn't make it any more challenging than it has to be. At least not at first.
    Last edited: Feb 6, 2018

    Gquebed Well-Known Member

    Totes instead of a big table?
    Very interesting...

    I wonder what advanatges there might be to this? Just cost savings? Or is there more behind this?

    I would agree with the above though... before you go all out with this it might be best to do a run or two with dwc bucket to get the fundamentals of hydro down. And that experience may tweak your design plans...
    Larry3215 and JSB99 like this.

    rkymtnman Well-Known Member

    you aren't going to have much room for a plant in there. your ebb/flow design's got to be 24" tall ? and a bit of space for the leds and then a bit of space b/t leds and plant tops.
    Major Blazer, PetFlora and JSB99 like this.

    JSB99 Well-Known Member

    I missed those dimensions. A small dwc might work, but with that amount of space, I'd just do soil or coco. With hydro, you're going to run into heat issues with your water anyways.

    Larry3215 Well-Known Member

    Thanks for the help and advice!

    I looked at Waterfarms, DWC buckets, hempy buckets, NFT, etc etc. I really liked the idea behind ebb/flow, but decided it was going to be a bit too complex and $$, so I had decided to do a DWC bucket instead. Waterfarms and hempy buckets and other simpler techniques just didnt run my motor.

    But, then I ran across several videos on (non weed) hydroponics during my searches, that made me change my mind about how difficult and complex ebb/flow was or needed to be. The key thing being that you really do not need any timers, float switches or submersible pumps to do fully automatic ebb/flow. Plus you can do it for significantly less cost and with higher reliability. The only serious failure point being the air pump, which I could replace with a quick trip to the pet store if needed. Another plus being that, with no mechanical pump in the rez, I am hoping my water temps will stay in the proper range with out needing a chiller of any type.

    Turns out growers all over the world have been using these techniques (automatic siphons and airlift pumps) for decades. Automatic siphons have been in wide spread use since the early 1900's at least, and airlift pumps have been around since people started using aquariums, and building backyard ponds.

    You are correct though, for some reason, they are not being used in growing weed. At least, I have not seen anyone else doing it this way.

    I should also point out that growing in soil is working just fine for me, but its boring. The idea of trying a "hi-tech" growing method like hydro , and especially ebb/flow gets me much more interested and brings out my inner geek and makes me want to experiment and try things out. Thats the real reason for this experiment. I expect to get enough yield from my soil grow to last me at least 6 months, so Im not that worried about blowing it on this grow and I have plenty of seeds to last me through at least several more grows.

    So, yeah, there is a good chance I will blow this badly and ruin an entire crop, but I will have a bunch of fun in the process. If I do fail, Im pretty confident it wont be because of the siphons or airlift pumps. So far, that all looks to be very reliable.

    JSB99 Well-Known Member

    I hear ya. I built different hydro systems in my first couple years, then ended up right back where I started, with DWC. If you can get a bigger tent, I think you'd find it much easier.
    Smok3yMcChok3y and Larry3215 like this.

    Larry3215 Well-Known Member

    The main reason for two smaller totes, instead of one large one, is so I can grow two different types at the same time without having the roots get all mixed together. That way, if one finishes flowering sooner than the other, I can harvest it without leaving roots behind to die mixed in with the other plant.

    Thanks for the feedback!!!
    Cold$moke and Gquebed like this.

    Larry3215 Well-Known Member

    My drawing wasnt very clear on that point. My grow tent sits on top of a table 30" up off the floor. The only part of the ebb/flow equipment thats going to be inside the tent is the two small totes with hydroton, and most of them will be below the table the tent sits on. Im going to cut holes in my work bench to recess the two totes so most of the tote is below the bench top. The totes wil only stick up about 2" to 3" inside the tent, so I will have at least 45" total height to work with. I am only growing relatively short strains so far, so that should work out ok. That will also help with heating of the water. My tent stays in the 72 to 79 deg range, which is too hot for the water from what I have read.


    Larry3215 Well-Known Member

    Im hoping to avoid the heat issues with this setup. By not having a submersible pump in the rez - or anywhere - that should help a lot. Plus keeping most of the grow pots under the table top will help too. Im also going to insulate around the sides and top of the totes on the parts that are inside the tent.

    Im hoping all of that will eliminate any hot water issues. I wont know for sure until I can set it all up and let it run with the lights turned on full though. That will have to wait a few more weeks until this grow is done.

    If I do have heating problems, then I will have to re-think the whole thing. I really dont want to mess with chillers.
    Ltcgrower likes this.

    Larry3215 Well-Known Member

    Yeah, I wish I had more room, but Im stuck with this size. The wife wont give up any more inside space to my smelly hobby! :)
    Budley Doright

    Budley Doright Well-Known Member

    I found my 400 gph adds about 3-4 degrees f to water temp. While it is possible to grow with out a chiller, I would highly recommend one, more so if growing in hot climates, but like I said you can get away with it, once I get over 70 shit starts to happen and growth suffers. Sharing the same res with differentl strains is also not recommended due to different needs but can be done. Just go ahead and do it, it's the best way to learn. You find out pretty quick what needs to be corrected. I to switched to hydro with only the basics and pretty much went right to ebb and flow. Spent the whole time waiting for the girls to die lol. The air pump may not provide the needed flow to keep fresh water going to all the plants but again try it and see. Nice concept :).
    Larry3215 likes this.

    Larry3215 Well-Known Member

    LOL!! I know that feeling of "I'm gonna wake up and they will all be dead" very well!! :)

    Ive been a little concerned about that aspect of running two different strains too. Im running Northern Lights and Critical CBD (both from Nirvana fem seeds) in soil at the moment - 2 pots of each. Im 3 weeks into flower, and while it hasnt been really serious, there has definitely been some of that going on with this grow. For example, right now one of the CBD's is showing some signs of tacoing leaves, and one of the NL's has just the faintest hint of yellowing leaf tips, but the other two look almost perfect. Im going to ignore both problem plants unless it gets worse.

    Now that you have reminded me of this problem, I will probably just run a single strain on this next grow. I had wanted to pick which ever one of these current plants I Like best and run it with the freebie seeds Im getting, but I think I will just stick with the freebies. Im going to have enough meds from this grow to last me until next fall probably, so I think I can afford to go with a single strain.

    This time of year, my grow room stays right around 65 deg or less, so Im still hoping I dont have any heating issues with the rez water. We will have to see on that though. I dont plan to grow in the summer at all. I'll wait until it cools off again next fall.

    Thanks for the reminder and the tips!!

    Larry3215 Well-Known Member

    Oh - almost forgot to address your other concern about the air lift pump flow rate.

    Thats my least worry at the moment, but your comment has me wondering if I missed something?

    So far Ive only tested it with a single tote with no hydroton in the tote, so Im pumping 5 gallons of water total on each ebb/flow cycle. Im assuming that the hydroton will displace roughly 1/2 the volume in the totes once I add it, plus the roots will take up a good bit of the volume too after they get going. So, once things get started, I should actually be pumping under 5 gals on each cycle.

    In my tests so far, Im able to pump 5 gals in just under 10 minutes, and Im pretty sure I can get that down to closer to 5 minutes with a few more small tweeks. At ten minutes fill time, and a 3 minute drain time, thats a cycle rate of a little better than 4 times per hour. Im pretty sure I can get that up to maybe 6 or 7 times per hour pretty easily.

    Is that not fast enough?

    I was actually thinking I might be better off slowing it down some. Ive read several threads where people are only cycling every few hours, and others that cycle much faster. I was kind of thinking it really isnt all that critical how fast the cycles are. Between Waterfarms, DWC, hempy buckets and NFT, the amount of time roots spend in water is all over the place.

    As far as going slower, the limiting factor so far is the automatic siphon. If the fill rate is too slow, the siphon has a hard time 'tripping'. So far, Ive managed to get the fill time down to around 30 minutes and still have the siphon trip reliably. There is one more variation on the siphon I want to test that may allow me to slow it down some more, but I cant test that very well until I get the totes mounted where they will end up. The relative heights of the totes and rez also effect drain and fill times, so I need to eliminate that variable first.

    In any case, if it doesnt trip, then the totes end up full of water and dont drain, so thats a bad thing. Im not toooo worried about that happening as long as I catch it before too long. At worst, I think it would be like running an RDWC with the roots in the water full time, except that I will have much higher % of roots in the water. As long as the air lift pump is running, I will have aerated water circulating through the roots at between 5 and 30 gals/hour. Im going to keep the max water level about 2"-3" below the tops of the totes, so hopefuly, that will also help keep the roots from drowning if the siphon doesnt trip.

    It just occurred to me that keeping the water level down 2"-3" will also reduce the volume of water I'm pumping and speed up cycle times even more.

    Larry3215 Well-Known Member

    It just occurred to me - if they dont work out, I could easily modify the auto siphons and just turn this into an RDWC setup. All I need to do is change the siphons into a simple overflow drain which sets the max water level.
    Budley Doright

    Budley Doright Well-Known Member

    It sounds like u gave this a lot of thought, way more than I did when I started lol. I'm still trying to figure out what type of setup I'm running next, going to change to seperate pails and possibly RDWC, DTW, or Recirc drip, so many options lol.
    Larry3215 likes this.

    Larry3215 Well-Known Member

    I have been back and forth over this, and changed my mind many many times over the last several weeks. The way I finally started to narrow it down was to make a list of the things that were important to me and that I Liked about each different option.

    1) cost - Im retired and on a fixed (not enough) income.
    2) Draining and filling the rez had to be easy. I did not want to use a pump to do that, so that meant raising the rez high enough to get a 4 or 5 gal bucket under the drain. Plus the rez had to be positioned so it was easy to fill.
    3) I wanted a setup that did not need a water chiller or submersible pumps or store bought air stones (I make my own) or float valves or timers - mostly for cost reasons.
    4) It had to be hydro of some sort.

    Then I went through the various options and made a list of things I didnt like about them and things I did. I finally decided that ebb and flow was what I really wanted, but it was going to be too expensive to setup, so it was going to be DWC, with an air driven drip. More or less like a waterfarm but with some minor mods.

    While I was researching better air driven water pumps, I ran across the info on the automatic siphons and the improved air lift pump. Thats when I realized I could do ebb and flow on the cheap - about the same cost as doing a DWC or waterfarm.
    Budley Doright

    Budley Doright Well-Known Member

    I figure I have about $100 invested in each of my actual grow containers. That's withou the chiller and passive cooling systems, yes im pretty cheap as well lol. Chiller cost $225 all in, and two hours to build but my passive cooling is a tad more complexed, but it has the capabilities to do both water and air using chiller as second stage. I love to build shit and while I have great results with my setup I need to change. I can leave my set up for a week, but yes if the pump fails I have 2 days to notice before plants suffer. I use a stack tote setup with 6 in each. As you begin there will be things you'll tweak, that's the fun part and possibly more cost, not so fun lol.
    Larry3215 likes this.

    Larry3215 Well-Known Member

    Thats about what Im going to have in this setup for the basic hardware and the hydroton. About $45 for totes and plumbing fittings and hoses, $35 for the airpump and $25 for hydroton.

    Do you have details anywhere about your chiller and passive cooling system? Id love to read up on that stuff.

    It occurred to me last night that I can reduce heating in the water even more if I can seal up the top of the totes around the stem of the plants and work it out so that the air comes into the hydroton from under the table instead of the grow tent. If I only have one plant per tote, and do a scrog, that will be pretty easy. If I do a SOG, that may not be practical.
    Budley Doright likes this.
    Budley Doright

    Budley Doright Well-Known Member

    IMG_4344.JPG IMG_4342.JPG The chiller is a window shaker that I replaced the evap coil with a water coil (tube in tube). Probably not a DIY type of build but I'm a refrig mechanic. I looked at buying an actual chiller but the cost for a new one (10,000 btu) was triple or more :(. My passive chiller is a 200' underground glycol loop that use tube in tube heat exchangers to chill the res water, pumps are cycled using digital aqua stats. As soon as it warms up a bit I'll head out and take some pics of the setup. All of my heating, humidity and ventilation is controled by a wifi stat as well, I like to tinker lol. I've shut the grow down since last spring but plan on plugging it in again as soon as my seed order arrives, been really busy and still have lots left from the outdoor grow
    Larry3215 likes this.

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