Hello! Ive just got my new system up and running and your seeing my plumping in the middle of a rework. Before I cut to many pipes and give myself a bigger headache I thought I'd ask the community to help verify what might be going on and ensure I am solving the problem in the right way.
The system can be seen here: http://imgur.com/a/kU75t
Where I am currently at: I Have a sump tank with a single pump in it pumping upwards. This splits in 3 places - about 25% up to a return back into the sump tank, about 75% up it connects over to the plumping that feeds the grow bed. Then at the top it dumps into the fish tank. The fish tank drains from a gravity drain back directly to the sump, keeping the water level in the fish tank constant. The 3 grow beds are all flood/drain systems setup with a bell siphon, all working correctly.
My issue: Over time the water coming out at the top of the pipe, into the fish tank loses power and eventually stops. This means no water making it to the fish and is obviously a bad thing. If I stop/Start the pump, plenty of water making it to the fish, good power, etc. I assume this is because I have bleeds located below this point and over time gravity wins and takes all the flow into this pipes instead.
My idea to fix: I am guessing that I need to run all piping to the maximum high (top of fish tank) then T from there and have it feed down to the grow beds and seperately into the fish tank, that way 100% of the water makes it to the maximum height and is then just forked to its ultimate path.
Anything else that can cause this? Im assuming this is due to the waterlevel fluctuating in the lower sump tank so the head heigh is variable. When the sump is very low (when the top tanks are all about to drain) the pump has to work harder to push another foot or two upwards which results in lower flow to the top? Any way to work around this? Am I misunderstanding the problem?
You have the right idea. Pump from the sump to the fish tank only. Looks like you are using 1" pipe. I did the same thing and found the fish tank wouldn't drain fast enough and would overflow. I added n overflow pipe to help with that but the right answer is to go with a 2" SLO pipe distributed to the 3 beds in smaller pipes (and an overflow). As your fish grow in size or numbers you may need to add a radial or swirl filter to separate the solids before they go to the beds.
Not sure why it would loose power unless the water level goes down in your sump causing loss of lift from the pump. When I set mine up my problem was pumping from an in ground sump up 10' and over to the fish tank. I bought a larger DC pump with 6 pump settings. If my sump is at a higher level I run it on setting 4 but as the water level goes down I bump it up to 5. With 3 grow beds your sump will vary in water level substantially.
Could be that you need that extra 25% that you're sending to your row beds to re-prime the upward line to the fish tank. Shut off the grow beds and see if the problem persists.
Somehow this did not post correctly:
Blake, I am limited on time here but please do not make the mistake that I see way too often. You are running a cold blooded species (fish) septic plant on a miniature scale. All sump water should go to the fish tank(s) first and or to a bypass back to the sump (if you have more pump than you need at present). DO NOT send it to the gravel beds but rather ALL the FISH water should go directly to the media beds (via a swirl filter is fine but not necessary). If you are also running a DWC or wicking bed then that should be only fresh sump water and that calls for a T. The media beds are the heart (or digestive system) of your system. That is where all the bacterial magic happens and the fresh water leaving the beds should drain back to the sump.
Now in regards to your loosing flow from the pump: it sounds like air is getting to the impeller causing cavitation. Is your sump big enough? It is there to store enough filtered water to make up for filling growbeds. The fish tank level should always be full with your set up. I will post a picture of my flow in hopes that you will glean something from it as I need to run. I'll check in later.
Thanks for the help and ideas. I have some things to try come this weekend. Will post results!
Okay, so here is what i've changed so far:
I've adjusted the plumbing so that all water goes to the top of the fish tank (height wise) then there is a T where some goes to the fish tank and some goes directly to the pipe feeding the grow beds, this seems to have resolved my pressure problems for now - but I want 24 hours without an issue before I mark this off the list.
Im now left with a problem with my bell siphons. While I youtube/google I figured I'd ask here and see if one of you experts knows my problem and can help me get this resolved quicker :)
The way I have the beds plumped for return I have:
Bed #1 - Returns directly to the sump - the bell works great here - as soon as it starts to drip, within about 15-30 seconds the siphon triggers and things return, this bed requires lower flow than the other beds to trigger the siphon.
Bed#2 and Bed #3 - These are both plumped together for their return to the sump through 1.5" pipe (The large pipe returning to sump) - All 3 standpipes are I believe 3/4 inch - its been about a year since I plumped that part. They adapt down underneth into the larger format pipe. Regardless - Both beds here will start to drain, but it seems to take both beds being flooded to trigger one of them to siphon, once its done the other will siphon and both are drained.
I've measured my bells and standpipes and while the standpipe is a different size in bed 1 (due to bed depth) they are all the same proportions. 12" stand pipe, 15" to the top of the bell, about 1.5" of holes in the bottom of the bell pipe to allow water in from the bottom.
To be clear: The siphon works, once triggered. it seems to take a long time to trigger. Do I just need to shorten the bell pipe so its closer to the top of the stand pipe?
Unless your fish tank has a draining problem all the sump water should go there. If you need to divert some of the water divert it back into the sump. All the media grow beds should get their water directly from the fish tank. The beds are your filter and the nutrients come from the fish tank.
As for the bell siphons, as long as they all eventually trigger then there's no real problem other than all the water that the 2 beds hold together. Jim is the siphon expert. when he gets back on I'm sure he can answer your siphon question thoroughly. Check out his profile here and facebook page Smoky Mountain Aquaponics.
Thanks for the reply - I am kinda in your camp as far as "as long as it drains at some point" - but the OCD part of me wants them to each work independently. From doing some quick reading I think the problem is due to plumping these two systems together, there is not enough back pressure in the drain pipe under the bed, which is larger than the bed thats solo plumped. 1" compared to 1.5" pipe. This requires both beds starting to drain to create enough flow to trigger the siphon. Hoping Jim can help clear up where I might be going wrong. I am going to get some pictures of how the standpipe connects and plumbs together to see if you guys can help :) im almost 100% operational!
Hey Blake, having made nearly 2000 bell siphons for AP I am sure your problem is one of co-mingling as you mentioned. They MUST be independent of each other and should always have an air gap after the one or two 90's or even if it drains straight into the common return pipe like my wicking bed does. They will always interfere with each other otherwise. Here is a picture of our 12" media x 1" pipe model for reference in case it helps. The 2 rings are just for raising the level for seeding direct or seedlings so don't be confused by those. They just get dropped into the 2" funnel top.