Alright i just got my new ebb and flow set up complete...i have a 7 gallon tray from HD...and a 14 gallon res....it takes around 3.5 minutes to fill.....what i need to know is how i can get a timer to go on for 3.5 min....around 5 times a day??? and also when the tray drains there is still around a 1/4 inch of water left from the fill drain..sits higher than being flush with tray??? Is this alright or not?? I tipped the one side higher but it still doesnt drain all the way... Any suggestions??? Please....Thanks

well i just adjusted my pump to go slower....so hopefully i can get something working...what do you guys recommend for a starting schedule for the flood times...around 4 times a day...my lights go on at 10....so i was thinking maybe 10,2,6,10...no floods during the night..???? any suggestions

You don't want it to fill and then drain immediately once its full; you want the roots to have a few minutes to soak up the nutrients. I leave my pumps on for 15 minutes at a time and it takes around 2 minutes to fill them and about 3 or 4 minutes to drain. Just make sure you have a cut off point where if the water gets too high, it will drain back into the res. My pump schedule in veg is every 4 hours (24 hr lights), and in flower its one hour after lights on, then every 2 hours, then one hour before lights off. You will find that a lot of peoples' pump schedules vary, so just start with 2-3 hours between pumps and see how the plants take to it.

As far as not draining completely, it could cause problems like root rot and such, but as long as all the roots aren't completely in water and your res temps aren't too high it should be alright. I used bins that held about 3/4" of water at all times for 6 weeks with no adverse effects, and had to switch back to them because my new ones I made broke, and so far nothing bad has happened (knock on wood). 1/4" is nothing really when you take into account the entire area of the roots. If its just the tips that are sitting in water, you should be alright.

__________________
The above post is fictional and should in no way be taken as truth.

If I were to grow cannabis, I would only do so to supply myself and my close friends. Doing this would take myself and my friends out of harms way by knowing the source of our cannabis, as well as take hundreds of thousands of dollars off the black market annually. It would also lower the demand of black market cannabis, and would ultimately help keep cannabis out of the hands of minors.

ok thanks alot...i dont have plants in yet...i am just getting it right before i put them in....yea i found a point where it takes around 20 minutes to fill and then stays on till 30 minutes because thats the interval on my timer....and then drains....in 8.5 minutes... do you think this will be alright????

At the big L hardware store, I bought a digital timer for about $18. You can set it to run up to 7 events per day, for any amount of time each.

By buying a cyclestat, which is a fancy word for $140 timer. Otherwise you can't, without using an elaborate system of ropes, pulleys, tipping buckets, and floats. That is unless you get the next best thing, which is the timer that gainesville told you about. I'm pretty sure that it's Intermac brand, and is under $20 and available everywhere your fine timers are sold. The one I'm thinking of has 14 on and 14 off times per day, which would cover what you want. The cyclestats are nice because they have infinite control over both frequency and duration. They don't come on at a certain time, but just keep repeating a pattern. Really good for rooting clones, but I digress.


Yes this is fine. It is the nature of all hydro, due to the fact that it's very difficult to put a hole in the exact bottom of the side of a tray, and still be able to get a fitting in there with a properly sealed grommet around it. This means that when you replace your reservoir water, you'll have a very small amount of the old stuff mixed in. Each time the extra left in the reservoir will be higher in TDS, but not nearly enough to hurt anything before harvest. Sometimes I do just what you do and tip the tray to get a little more. You can get nearly all of it this way depending on your setup, but it doesn't really matter. It is actually desirable in some situations (like mine) to have a small amount of water in the tray at all times. If the power goes out while I'm on vacation, the plants won't die of thirst.

__________________

I don't see why an on time of 30 minutes would be a problem. What matters is the off time. You want it off as much as possible so the roots can breath and air out. For best results you should have an air stone at least, but preferably a power head pump in your reservoir that injects air and circulates the solution. Put as much oxygen into your solution as possible to help avoid root rot. Also if you are worried about that you can add a little hydrogen peroxide. For 30 minute intervals I would say maybe try 30 minutes on and 3 hours off. Since a little of your roots will be in nutes at all times, it probably won't hurt much to have a long off time. Don't get too long though, because you don't want the fine root hairs to dry out and shrivel up. You may want to start with 30 on and 30 off, and work your way up to longer off times, while you pay close attention to what each change does.

__________________

ok thanks a lot opie!!!! you answered my questions exactly how i needed....So i will start with around 3 hours between and see how that works for now.....thanks again!!