Flood and Drain Cycle Timing

[Mario]

Hello,

I am a newbie setting up my first system and I had a cycling time question, I have a 100 gallon system and a large pump, my flood and drain cycle is 5 minutes total and it cycles 8 times per day is that proficient?

Thank you for your help.

[Meg Stout]

How large are your growbeds? What is the capacity of your pump?

Cycling only 8 times a day for only 5 minutes seems pretty infrequent. The rule of thumb for your fishes' sake is to cycle the entire volume of the water through the grow bed every hour.

Good luck!

[Mario]

Thank you for your reply Meg.  To answer your question my grow bed is 4x8ft and 6in deep with a hundred gallon fish tank.  I cant remember the pump rate but it is fast, after restricting much of my flow with out bogging down the pump it takes less than 2min to fill and 4 to five min to drain.  Was thinking of possibly taking my 1inch drain and putting a half inch nozzle on the end to slow it down.  Also I am trying to find a digital pump timer that goes down to the minute and will allow for 24 cycles per day. My current hydrofarm timer only allow for 8 intervals per day.

Meg Stout said:

How large are your growbeds? What is the capacity of your pump?

Cycling only 8 times a day for only 5 minutes seems pretty infrequent. The rule of thumb for your fishes' sake is to cycle the entire volume of the water through the grow bed every hour.

Good luck!

[Meg Stout]

OK, given those dimensions, your grow bed holds 120 gallons (if it is full to the top). For simplicity we'll call it 100.

Usually you can put 25% of your grow bed volume in as water before the bed is "full" because the rocks displace the other 75%. So if it takes 2 minutes to fill, your pump is pushing water at a rate of 750-1000 gallons per hour.

You could try using a repeat cycle timer (search them on ebay). They're relatively inexpensive and have pins so you can turn on or off in 50 second increments over a 40 minute cycle. I would put that in series with a regular timer that has pins for every 30 minutes if you don't want the bed flooding at night (when it's cooler outside and/or when people are trying to sleep).

[RupertofOZ]

If you're pump is too strong Mario.... cut a "tee" into the pump line, between the pump and grow bed... and divert some of the flow, (use a ball valve)... back to a spray bar above the fish tank/sump... it will provide extra aeration to your fish tank/sump...

 

8 cycle times per day... probably isn't sufficient.... get a cheap 15 min increment mechanical timer... and set 15/45... and you'll have 24 cycles per day...