Draining tables against gravity?

[yamaha_1fan]

purple, the original plan was to stick to what I know, which was E&F tables and hydroton. Switching mediums, and watering style equals a new learning curve, probably not much if things go well.

The recirculating is not an issue if I do drip. Its the E&F that creates a problem by bot being able to drain backwards


Hydro, the tables are off the ground and I do have a small res with a pump to catch the water. But when you flood a table, the water runs backwards through the pump when it shuts off. It can not in this situation because of gravity. Somehow I need to open the fill line when feeding is over to allow everything to drain.

 

[purpledomgoddes]

suggested building a rectangular, low-height rez in smurfing' herb's thread. not that difficult.
can be 8" tall*24" wide*24* long. will get you a bunch of gallons in there. did the math too, in another post. basically, a 1 cubic foot container will hold ~7 gallons.

can use fiberglass/polyester resin+fiberglass tape/cloth to water proof it. sidewinder in joints, epoxy optional (strong as a rock once set).

why is a low-standing, wide+long rectangular rez, that fits under your table, not an option? you can build a simple 1 cubic foot box, seal it, test for 24 hrs (flood test). see how it works/doesn't work for you. if viable, build bigger one.

if uncomfortable w/ resins/fiberglass, etc., just throw some pond liner on an old dresser drawer. should be low+wide enough to hold 20+ gals, while staying under low table.

for gravity drip, can simply pin-prick tiny holes in hose/feed lines. line 1 tiny hole per plant site. over a day or so, a tiny hole can flow a lot of water. for no automation, just get very large sponge, soak water out of table, end. maybe too low-tech, but simple.

just a few options. hope this helps!

 

[yamaha_1fan]

I didnt want to keep the reses in the room under the table for two reasons. First is heat. I wanted to keep the reses out of the room since we will be running CO2 and 85 degree temps. The reses will stay cooler outside. The second is maintenance. With all the reses outside, we can check nutrients, PH etc, drain, fill, add back, etc at anytime lights on or off.

I already run E&F tables so my design was to make the whole operation super simple. draining reses before lights go off, or pumping them out sucks donkey balls. All the reses will be tied into one drain, and will have PVC run to them for easy water access.


I found a valve that will work. If this valve works, then all is golden.

 

[Hydro-Soil]

But when you flood a table, the water runs backwards through the pump when it shuts off. It can not in this situation because of gravity.

Ummmmm..... Gravity is still your friend here...... that's why you turn off the pump in the main res after a feeding. Right? Gravity empties your bed into the small res underneath and the pump from that res pushes the nutes back into the main res.

An anti-siphon valve like the 1/4" irrigation valve popped through your main delivery line should be fine to keep the entire res from draining into your bed after the main pump stops.

Once it reaches your bed you already have the small res and pump idea in place. (sorry I missed that in your original post.)
Just be sure that the float you have in the smaller res is shielded against water turbulence so that it runs constant without triggering an on/off stutter. I hear it's murder on pumps and electrical systems.

Hope that helps.

 

[been]

The inline pump would work, but that would require a 3rd pump.

One pump to pump to table.
One pump to pump from table to rez
One pump to pump overfow back to rez.

No man, you're missing my point.... you don't need a drain riser/overflow if you control flood level with a timer. You don't need a pump in the table at all. Instead of letting the overflow fitting control the flood, you time it so that it stops, and when the flood cycles is over, the water level will settle back through the inline pump. Then you turn time that one to shutoff when the table is drained....... no riser necessary, dig?

 

[yamaha_1fan]

Ummmmm..... Gravity is still your friend here...... that's why you turn off the pump in the main res after a feeding. Right? Gravity empties your bed into the small res underneath and the pump from that res pushes the nutes back into the main res.

how is the water going to get into the res under the table? The feed line is a solid connection. Once the pump shuts off, there is no opening, or way for the water to go from the table, to the res, unless I use a valve to open the line. Or just use an extra drain that is smaller than the feed line and fill faster than it can drain, but I already explained the issues with that.



Been, that would be extremely complicated and the possibilities for a flood are high. First I am using one timer, to run 4 pumps from 4 reses, to 8 tables. Then there is another timer for 4 more pumps, reses, etc. During startup, each table may have more plants than an other while we experiment with SOG, get enough clones etc so each table would have different requirements. Plus length of piping etc may create unbalanced fill times

That wouldnt be a bad idea in a single table/res application.


Another issue is the whole place was built to a plan so wiring etc is already installed and changing pump configurations would be problematic.

The valve is $50. 8 needed in total so $400 will fix the problem with no rewiring, configuration etc

 

[Hydro-Soil]

how is the water going to get into the res under the table?

Most peeps have a drain hole.
You pump the nutes from the main res into the table. It DRAINS from the table through your drain hole into the lower res.

Once you shut off the pump from the main res, the table stops flooding.

As the lower res fills it triggers the float valve and the pump pushes the nutes back into the main res.

The feed line is a solid connection.

I think that's your whole issue there. Everything should be separate from each other like the toilet in a bathroom that's below the sewer line.

When you flush the toilet the water comes from the tank on it (your main res) and flushes through the toilet, out the bottom of the toilet and into a small reservoir.

Once the toilet and other sinks and stuff have dumped enough water into this small reservoir, the sump pump kicks in and pumps all the waste up and into the sewer line.

Your application is the same. Your main res is the toilet tank. The bed is the toilet itself and the pit that the sump pump sits in is your lower res.
The only difference is that instead of pumping your lower res to a sewer line you're pumping it back into the toilet tank (your main reservoir)

Does that make sense?

 

[yamaha_1fan]

Most peeps dont have a drain hole. They have two holes, a fill hole and an overflow hole. Once the pump shuts off then the table drains backwards through the pump. No need for a third drain hole

What you suggest would require a third hole that would allow the drain to remain open all the time but be small enough to allow the table to fill up faster than it can drain. That makes for a slow draining table, and can clog easier


I already have two lines running to each table, a feed line and a line to go back to the main rez

 

[Hydro-Soil]

But when you flood a table, the water runs backwards through the pump when it shuts off. It can not in this situation because of gravity.

You're still looking at things backwards

Essentially you need to restrict the drain from your bed to the lower res so that your table fills properly. The nutes come in faster than they drain.

You'll also want an overflow that goes into the LOWER RES from the table. Obviously this will prevent the table from overflowing but your extra from the main res pump will go into the lower res as well.

This way everything goes into the lower res and gets pumped back into the main one.


Am I missing something?

 

[Hydro-Soil]

That makes for a slow draining table, and can clog easier

If you set the size of the drain hole correctly it will drain just as quickly as it would through the pump in a normal setup.

ANY table will clog if the holes are too small and you have too much crap in your water. I wouldn't worry too much about this.

It will definitely take a lot of work to set up correctly where you won't need to be tweaking anything to prevent floods.


I'd be prepared to do some extra plumbing or spend my time and resources looking for some other place to put this.

 

[gdawg]

yamaha with everything you got goin on (size)and takin the jump to coco, make your life 100 times simpler by going to drip, run to waste. keep your rezs out of the grow no problem, your tables can be lower, way less pumps to fail on ya, and you will get to where you havent used a ph meter or ppm in months but still know exactly what your rez is sittin at. it is sooooooo simple and low maintenance and people misjudge about how much waste there is, i have hardly any. thats just my but what do i know i havent recircd in over 2 years and have forgotten what its like to flush a plant in midcycle because of ph fluctuations or nute burn....or had to check my rez ph....

 

[Hydro-Soil]

I SEE the issue now.

You're pumping nutes from your main res into the table from a Hole UNDER the table, Right? This is your problem. It interferes with having a main res higher than the table. (As you've found)

Re-plumb to a dump line that just drops into the TOP of the table. Put it in a mesh basket if you need to slow the water surge.
Problem solved.
*** Edit ***
You may wish to plumb a manifold to split the feed lines to several drop points on the tables. This way you can fill the whole table evenly. (generally takes less time and gives a more even wetting for all the plants)

 

[manitu]

Why not use the feed line as return line too? If you can drain back trough the pump , it should be possible to pump trough another pump?

With electronic timers , you should be able to get the correct fill-level , without overflow.
Then, you could run the emergency runover directly into the drain.

By the way , simple solution to the siphon problem , poke a small hole in the feed-line , wich drains back into the reservoir. When the pump stops , this hole will suck air , and stop any siphoning.

.manitu