Stand Pipe Flow Question

[B. Pearcy]

I think I'd like to skip the Bell Siphon altogether and use a pump on a timer and then just rely on holes in the stand pipe to empty the grow beds. Is this reasonable as long as your pump has a large enough flow to outpace the stand pipe drainage? 

Using this approach, what suggestions do you have for "tuning" the stand pipe with less or more holes?  I'm guessing a threaded stand pipe of some sort would be adviseable so the pipe can be removed without disturbing all the grow media.  I'm thinking it might be better to adjust the pump flow by routing the extra back into the fish tank, but even that has its' own variables. Am I on the right track, or completely off base?

Is this stand pipe only approach better or worse in a deep grow bed like a 100 gallon stock tank versus a 50 gallon stock tank?

 

 

[TCLynx]

Yes as long as your pump can fill the bed in the allotted time before the timer shuts off, then the flow is large enough.

 

You want the stand pipe installed in such a manner that you can pull it out to adjust the holes (or like me I sometimes flip it over to do constant flood.)

 

I just plumb into the deep bed and then place an elbow.  The stand pipe sits into the elbow.  So make sure you drill the holes above where the pipe fits into the elbow.  I would start with two holes of perhaps 1/8" to 3/16".  And then see if the bed fills fast enough for you but still drains fast enough.  If it drains too slowly, add a third and check again and so on.  I've found that a bit of electrical tape over a hole can help if you go and make too many or too big.

 

I've only ever done one auto siphon on a 100 gallon stock tank grow bed and it is an external u bend siphon that needed an air breather.  If you can do the stand pipe and timer, that is simpler but may mean you need to add supplemental aeration for when the pump is not running.

 

Yes, your idea of bypassing excess water back to the fish tank is viable and definitely recommended for situations needing to fine tune water flow to get siphons working properly.  To do a bypass back to the fish tank, simply add a T after the pump and one side goes to the grow beds while the other side goes back to the fish tank with a ball valve on it to adjust how much water is allowed to spray back into the fish tank.  And it is good to set it up in some fashion that will spray the fish tank and improve aeration.

[Chi Ma]

TC is on the right track.

[Lonny Harper]

Would it work to use a valve in the drain pipe (under the grow bed) to adjust the rate the bed drains?

[Chi Ma]

It could work but the risk of it gunking up and flooding is not worth it. It's better to control the flow going into the grow bed. 

Lonny Harper said:

Would it work to use a valve in the drain pipe (under the grow bed) to adjust the rate the bed drains?

[TCLynx]

Chi is right.  If you were to put a valve on the drain or any restriction on the drain of a bed, you should then add an overflow to the bed in another location.  Just seems like more cost in plumbing.

Have the stand pipe that you can take out and adjust the drain holes and height and be able to adjust the flow into the bed and you should be golden.

[B. Pearcy]

I wish I had stuck to that plan. I have to add an overflow pipe now. It is not that costly but would have saved me extra hassle. Funny thing is a picture using the existing bulkhead convinced me to make a last-minute change.

[Lonny Harper]

This sounds like a such a simple way of doing it.  I have yet to grow my beds, but this is probably how I will do it.  I must admit it's not as cool as the siphon though.  I glad you brought this up.  Actually, I've enjoyed many of your recent questions as they are mostly things I have wondered being in the planning phase myself.

 

B. Pearcy said:

I wish I had stuck to that plan. I have to add an overflow pipe now. It is not that costly but would have saved me extra hassle. Funny thing is a picture using the existing bulkhead convinced me to make a last-minute change.