CHOP system - water flow

[Erich]

Guys

Just getting my head around one of the last items on the CHOP system before I order my parts etc. This question is based on "water flows"

Firstly, I understand about the gravity feed to the GB from the FT and using ball valves to adjust the flow so as the siphon starts & works correctly.

Question is based around all the inflow getting pumped from the ST to the FT. Whilst the GB are fed via gravity, do you just adjust the inflow to the FT via a Ball valve as well? Im confused that there will be more inflow into the FT from the ST than whats going into the GB's, and if the volume to the GT have been throttled down via valves, that there is a chance the FT could overflow somehow? Is this all just throttled via valving?

[satori]

Yea i was confused on how the gravity line worked but as long as there is water over flowing down the pipe it would push the water back up the line into the bed.

[Erich]

overflowing down the pipe is fine however its "throttled"at the GB end via valves so you can ensure that the siphonn works. Thats the restriction there

[satori]

what do you mean? gb end? is that the auto siphon?

[Erich]

yes - the auto siphon

The water flow going into the GB is purely controled by taps/ball valves etc. Coming out is via siphon, once its full. However, a 4000 litre per hr pump will pump a lot of water into the FT. I dont want the ST draining empty cos the pump is pumping it dry

[Murray]

The amount of water flowing into the FT is equal to the amount flowing out.
Obviously there is an upper limit for the size of the pump, but that will be governed by the number of grow beds you need to feed with water.
Have you watched the DVD yet ?

[Erich]

The amount of water flowing into the FT is equal to the amount flowing out.

Murray, by what ive read so far, it appears that you need to govern the amount of inflow into the grow beds via a valve. To fast or to slow will play havoc with the bell siphon. This on its own may slow the water getting out if you need to throttle it back. So if its cut back a bit, and the pump isnt, FT volume will raise. If no valve is put on the GB's, thats different. Im missing something me thinks.


Obviously there is an upper limit for the size of the pump, but that will be governed by the number of grow beds you need to feed with water.

So when people say always go bigger, allows for expansion of your system, where will this "extra" go?



Have you watched the DVD yet ? Just need to get the theory understood before I purchase my stuff :)

[Jens UK]

Erich, I have wondered about the same thing, and my solution will be an overflow pipe from the ft back to the sump. so any water held back by the gb valves can drain back to the sump from the ft.
waste of electricity of course, but matching the the pump to the volumes required would be a good idea. I am currently using an old central heating pump with 3 speed settings.

[Erich]

Erich, I have wondered about the same thing, and my solution will be an overflow pipe from the ft back to the sump. so any water held back by the gb valves can drain back to the sump from the ft.


Thats what im thinking. Agree that all timed correctly, it will be fine - however, better to be safe.

thanks for the feedback :D

[Erich]

Watched the Secrets dvd. I see that there is no taps/valves on the GB side - its just gravity fed - I believe thats where i was geting confused (as opposed to having valves on it).

If I use a larger pump, I would think that I can use a valve to throttle it down to regulate the flow into the GT?

Thanks again for the DVD - its worth every cent then some :)

[Murray]

It is best if the pump is matched to the system needs.
There is a lot of latitude as the system gets bigger, more overall volume helps.
On our Homestead system 1 x 4500 ltr pump works everything just fine, but 2 x 4500 ltr pumps shortens the cycle time on the grow beds and the auto siphons work just fine.

[Erich]

Cheers Murray

However - do you see any issues of installing a valve on the line from the ST to the FT (by the pump) to throttle it down a little - therefore having a little control over the water flow out of the FT to the GT?

Now hurry up with the next installment ;)

[fishfood]

Its bad to throttle a pump put a t in the line and shoot some of the water back to where the pump is

[Murray]

As FF says, it is very useful to by-pass some of the water flow back to the sump as a way of regulating the water flow around the system.
We do this particularly on smaller systems where the pump is over specified to allow for the addition of extra grow beds later on.
By-passing the water and directing it over the surface of the water in the FT or sump provides useful aeration for the system. There cannot be too much aeration in an AP system, but there can certainly be too little, so every opportunity to assist aeration should be exercised.

These are good reasons to have a pump that has some over capacity.
1 Provision for future system expansion.
2 Provide an additional source of dissolved oxygen for the overall AP system.

[Erich]

Thankyou

clear now - will set up a t piece with a tap in the sump and bleed off extra into the sump. This will then allow the pump not to be throttled back and I can regulate the inflow to the FT better :)

[Jens UK]

I have my ft overflow positioned over the sump, so the excess (loads...pump is 3000l/mins.)
goes straight back in the sump.
once more growbeds are online, the overflow will adjust itself accordingly

2705

[Erich]

Cheers Jen

Im thinking I will need taps at the GB side anyway as even though the flow is gravity fed - it will fill the 2 different GB's up at different rates - will need some sort of control or build the outlet to both just dribbling out of a tee piece between them instead of individual piping

Jen - I see by yours - it looks like you tilt the overflow up on each GB and control the flow that way?

[chainsaw]

General Question,

Is there too short a period for the grow bed to cycle........eg. every 5 minutes would give good filtration and aeration but what effect (if any) would it have on plants.

[Murray]

The cycle time does not make much difference we have noticed....unless it is excessive.
No apparent effect on the plants so long as it drains well.
We had some beds set up so that the fill time was around 9 minutes and the drain time was about 50 minutes. The only detriment to the plants was with such a long drain time, the lettuce tended to wilt a little in the hottest part of the day.

[Jens UK]

hi Erich,

I have actually diy taps on the grow beds, the photo above is the sump.
I shall post some pics of the taps and my syphons and how to diy them in a new thead soon.

cheers

jens

[Erich]

thankyou Jen :)

I was looking at your other pics - and noticed 1 x 45 degree bend on the GT pointing up - thought you controlled the flow that way