Aquaponics - Hurdles

Been a pretty long time since my last post, mainly because I ran into some issues and had to re-evaluate my plan. 

First off, I ditched the loop siphons, just couldn't get them to work correctly. It really irks me that I couldn't figure out why but I tried NUMEROUS variations, even making loops out of hard PVC which I thought was going to work but did not.

 I think it has to do with the barrels not holding enough water to force the siphon to kick in. I say this because of one experiment I did where I had all the water flow from my pump coming into one bed instead of divided into the four beds I have. When I had all the water flooding one bed, the siphon kicked in fine. Now when I hooked all four beds up , they filled up and the water started draining back out at exactly the rate it was coming in at and the siphon never kicked on. IF, however, I smacked the siphon loop a couple of times, it would kick on and start the siphon and drain correctly down to the bottom. Call me crazy but sitting on a stool smacking PVC all day just wasn't my idea of fun.

 So, we move on to another plan. My next plan was to put a cheap timer on the pump and have it run for 15 on 15 off. I have installed an overflow tube at the top of the fishtank. My thinking was the water would drain out the tube at the same rate that it was being pumped in by the pump line, but it did not. The pump moved more water into the tank than was being drained out so the water level rose to over the top of the drain tube. I  suppose I would have installed a bigger drain line or multiples to make sure the water ran out as fast as it came in but honestly I got distracted by my next idea: using two pumps. THIS WAS A BAD IDEA ALL THE WAY AROUND. I planned on pumping water into the fishtank from the sump pump and at the same time pumping water from the fishtank into the growbed irrigation lines. Bad idea, it relied on one very poor assumption: That both pumps would move the same amount of water. Not true, even though they were the same model, the small difference in heights and a couple of other factors caused one pump to pump more water than the other which means that, either the sump tank would run dry eventually, even if only until the next cycle kicked in OR the fishtank would overflow. Here's the biggest mistake I made though, If both pumps are turning on at the same time and cutting off at the same time, then the sump tank will overflow because the water drains out of the growbeds even AFTER the pumps have shut off and when the pump turns back on, the water coming into it from the growbeds means the sumptank will not have enough time to "catch up" and will eventually overflow. Ah, so I thought, I will just reduce the flow the water going into the growbeds so as to make sure the water coming from the sumptank always moves more THEN I will put in a drain line so that when it does eventually over flow, it will drain right back into the growbeds. See what I'm doing here? I'm making up for faulty design by adding needless complexity to the system. Even if I had done this, the system would never had been perfectly balanced as the overflow from the fishtank would have probably overflowed the sump tank eventually.

Onto the newest idea. I stumbled across and ordered a float timer. I never even knew these things existed. the way it works is you mount the float to a piece of PVC by clamping it on at the level you want your pump to kick on. You then plug your pump into the outlet provided with the float switch and when the water hits that level it will kick the pump on and drain it back down to that level. This is a much simpler solution as it is reactive to the level of water in the sump tank, not time.

 My plan now is as follows.

Plug up my drain lines in the bottom of the growbeds and pump water from the fishtank into them until I get the water to the desired level. (about one inch below the surface of the gravel)

Make sure there is enough water in the sumptank to cover the pump so it won't suck air while the growbeds drain.

Set the pump float to that level of water.

Open the drains on the growbeds and let them drain fully into the sumptank and plug the pump into the float switch outlet.

Now, because I have taken the amount of water out of the fishtank that it takes to fill the growbeds, I know the water will never overflow the fishtank. Even if it somehow did, I have an overflow tube as well.

Once I have my float set I can drain the water from the growbeds into the sump tank, the pump should kick on very soon and pump until the float drops again below the desired water level in the sumptank.

I will still have the second pump in the fishtank on the timer to start the cycle every 15 minutes but 15 minutes should be enough for the drainage of the growbeds and the pumping of the water back into the fishtank, getting us back to the start of a new cycle.....In theory. 

Basically what is going in is I am adding a pump, which is triggered by the water level in the sumptank, to replace the loop siphons which I couldn't get to work reliably. I think I may eventually rework the drain from the fishtank to the growbeds with the intent of removing the pump from the fishtank but if I can just get this working as it is now I will be satisfied for right now. 

Oh, I almost forgot to explain how the beds are flooding and draining. What I did was replace the loop siphons with a simple piece of PVC with male threading on the end then placed a screw on PVC cap, I then drilled holes in the cap to allow the water to drain but not as fast as it would fill up. I then installed valves on the ends of the four PVC lines running to the grow beds so I could adjust the rate of the water coming in, to get them to flood quicker or slower. By letting the pump run in a few 15 minute cycles I got them to acceptable levels of flooding but I also installed overflow valves just in case. As it stands right now a couple of the beds drain pretty fast because I drilled 6-9 holes in the PVC cap but they still flood during the 15 minute cycle, I could actually lower the drain rate by putting a PVC cap on the drain line with less holes (maybe 4-6) and then reduce the water rate at the valve. This would allow me to add more grow beds as it seems like I would have enough flow even in 15 minutes to flood more beds.

I am supposed to meet a guy this week in Rome Ga to get my catfish. he is over in Alabama but comes over to Rome ever couple of weeks so that saves me having to drive to Alabama to get them. I have a few goldfish in the water now and they seem to be doing ok although I have lost about 12 or so out of the original 36. I am attributing that to the cooler temps at night as the water appears to be chemically ok and I know I have been feeding them.