Index valve

[B. Pearcy]

When should an index valve be considered?

[TCLynx]

When you want to have more grow beds than the water fluctuations in the fish tank can support and you don't want to go with a sump tank or if your sump tank is too small to handle the water level fluctuations for the amount of grow beds you want.

 

[TCLynx]

For instance, with my 300 gallon system where the fish tank is only 300 gallons and kinda shallow, for me to have 6 100 gallon grow beds doing flood and drain, I have to have an indexing valve because if I were to flood all beds at once there would probably only be 4 inches of water left in the fish tank.

[TCLynx]

When I had only 3, 100 gallon grow beds with the 300 gallon fish tank, it was still reasonable to flood all the beds at once so I didn't really need the indexing valve then.

[Philip J. Wolf]

Does the pump need to momentarily shut off for the next zone on the index valve to be accessed or does the valve have some built in timer?  If you use a timer what type do you use?  I could see rotating between 6 zones on a 10 minute cycle but I am not sure that would do the pump a lot of good to be turned on and off 144 times a day!

[TCLynx]

The flow to the indexing valve needs to stop for 30 seconds to a minute for the valve to drain and be ready to index forward.

 

It depends on the type of pump if you should do this or not.  Mag drive pumps really have little problem with such things but if you are using a bigger inline direct drive pump then you might want to consider other options, like perhaps using a solenoid valve between the pump and the indexing valve.  Just gotta make sure the pump can provide enough pressure to operate the solenoid valve and still get enough water through it for the indexing valve.  You will of course want a bypass a good deal of flow back to the sump or fish tank when running this way.

 

A repeat cycle timer is what I would use to either operate the pump or the power to the solenoid valve.  I'm still testing a few of them to decide which one is best but e-mail me if you are looking for one.