Backyard Aquaponics
A place to discuss aquaponics

So I'm going through my next plans for a couple more beds. First, I'm going to use the 300gl stock tanks instead of the 100gl. I'm going to go flood and drain. I can't possibly afford filling 600 gallons with hydroton so I'm going to find something suitable at Pebble Junction in Sanford. The beds are going to gravity drain back to the pond as my first bed does. One question I have - has anyone noticed a spike in energy use when using a pump on a timer? My thoughts are that the constant re-priming of the pump would use more energy than if I just left it run. My other question is of the sequencing type valves I've seen out here and at TCLynx's place. Can you use only two of the taps and cap the rest for future expansion? Also how are they timed/triggered. I know you explained them to me TC but I was already getting kinda 'full' upstairs and I can't recall exactly how they work. Thanks

The 1/2" brown river rock at pebble junction is probably the best choice of media. Pretty cheap and fairly easy to handle and it won't mess with pH.
If you have a place where you can get a big pile of gravel dumped, I would advise get a full 6 ton load delivered since it will probably take a good portion of 4 tons to fill two of those 300 gallon tanks so you might as well get a bit extra of the gravel anyway as the delivery fee would be the same for 4 ton or 6 ton.

Yes the indexing valves do have cams for being able to use smaller numbers of the outlets. If planning on using a pump on a timer, I would suggest simply hooking up one of the indexing valves from the pump. Each time the pump turns off then back on again, the valve will shift forward one spot. So you could run the pump 15 minutes on, 15 minutes off. So that would work out that one bed fills for 15 minutes the the pump is off for 15 minutes then the other bed fills for 15 minutes and so on. (The only reason mine has that extra junk-my low pressure automated valve- attached is that there isn't a pump feeding my indexing valve because mine is a CHIFT PIST system and the overflow from the fish tank is feeding my indexing valve.)

What pump are you planning to use to feed the new grow beds?

Originally I was thinking of using the same kind of pump I have for my first bed, a 40w Quiet One which pumps around 10 gpm. I was thinking of running it in constantly, changing beds every thirty minutes. Is it possible to put the indexing valve on a timer so that the pump never has to turn off, re-prime etc?

I saw on PJ's website that they also sell washed shell. Is that where you got yours? I figured I should probably add some as a precaution. What sort of ratio do you use as far as substrate/shells?

Yes I did get washed shell along with my first truck load of brown river rock. Problem is if you do that, they will be mixed together. I would suggest that you want to go get a few bucket fulls of washed shells when you stop by there sometime and just get the river rock by the truck full. It has taken over a year for my pH to even budge below 7.6 with the amount of washed shell I have mixed into the grow beds.

My first truck load of media was 3 tons washed shells and 3 tons brown river rock. I later got another 6 ton of just river rock.
I would wait till your pH gets down to about 7 before you add some buckets of washed shells into the flow somewhere. (like maybe have the drains from the grow bed flow through a bucket/basket of washed shells as it returns to the pool.)

As to the indexing valve, the easiest way to have it index forward is by turning the pump on/off. I'm also not sure if the indexing valve will work on 10 gpm, will have to check on that. I think the big one I'm using needs closer to 20 gpm available.
Anyway, it might be possible to set up some way to let the pump run continuous and use some other valve to control the flow to the indexing valve, essentially that is what I'm doing using a home made low pressure valve. Trick with running the pump constantly but only part time having flow go to the indexing valve might either put extra strain on the pump or have pressure differential issues.

With that quiet one pump, if it is strong enough to operate the indexing valve, would be more appropriate to simply running on a timer. Which model pump is it?

yeah, I was trying to avoid cycling the pump on and off to conserve power. The pump is AES part #QP13.

You are talking about a 40 watt pump there, I really doubt it will make much difference cycling it on and off. Think of it this way, yea it might take a tiny extra spike of power as the pump comes on but then you are saving all the electricity during the time the pump is off so it will even out to be less power used if you say run the pump 15 minutes on, 15 minutes off.

The alternatives might avoid having to turn the pump on and off but they would themselves need some power to operate and thus use even more electricity as the pump would be on full time and the timer/controller for an automated valve would also use some electricity. On top of that, there would be the additional cost of such a valve and the controller.

Now if you were talking about say the pool pump turning on and off or another large horsepower pump, that might be a different story but for the price of the extra stuff and tinkering involve in avoiding turning the pump on and off, you could buy a spare one of those pumps.