Backyard Aquaponics
A place to discuss aquaponics

I apologize for the way I phrased that. My siphon takes 30 seconds to kick on once at the max water level. The time it takes my bed to fill I haven't put much focus on, as that will decrease with my media in there. Which leads me to understand that I need to fill my GB before continuing for better results. I was just so focused on getting a working siphon I didn't realize how badly it was affecting things. The pump I'm using is a 400Gph Beckett.

My GB has a 26 gallon capacity and I have a 50 gallon FT.

The water level drops past the air tube but only for a split second, I'm ditching the air tube though.

I realized that the drain pipe seems to be drawn in diagrams where it's as long vertically as it is horizontally. I don't know how important that is but I'm going to fix that. My proportions aren't off by much, the horizontals just a little longer than the vertical.

But what about my crooked GB floor, no ones mentioned it and I hope it's not an issue but it still concerns me.

And it sounds like my standpipe should be smaller than 3/4 than?

If I follow the affnan model should I cut the dimensions in half http://4.bp.blogspot.com/_kiwWdODqX6M/S_JVslNNSpI/AAAAAAAACP0/8dLN2AbuK_M/s1600/Affnan+Valve+1.jpg? My bed is considered smaller right?

Done 4 years with siphons (+ 6 different systems), rarely had an issue. For me, my new systems i will do a couple of CF for the following reasons:

1. A "much" smaller sump is required
2. I don't really want timed as that increases failure points (pump failure (on and off), timer failure)
3. A smaller pump can be used, therefore less wattage, therefor less electricity cost
4. Trials have shown me the water clarity is great

No other reason, just the kiss method......

From my PVC pipe on roof experiment- i can tell you that the water takes ALOT longer to get to where its going with media in the way (when flowing in a single direction), however once it gets there and has built up enough it will flow at the exact rate as the inflow.

In a siphon system, if the inflow is cut when the siphon starts, i would expect that the siphon has to do alot of work, it may flow out at a decent rate, but will be doing more work to "suck" the water through the balls than if it was being "pushed" through by flow.

I think you may have well and truly oversized both your your standpipe and pump.

I had a system (as in my avatar) with a shallow bed that held 115L (30gal) of gravel, I had a 15mm (roughly 5/8) diameter standpipe and a 1200Lph pump (317gph) pump.

When the GB in-flow was tuned to get the siphon operating correctly the pump was throttled back more than halfway (diverted through spray bar on FT) and it completed a F&D cycle in under 12 mins. With the 3/4 standpipe you will need faster slightly faster flow than my system, but nowhere near the flow your pump can deliver, if the figures posted a few posts back for your pump are correct.

With you having a smaller gravel capacity and larger dia standpipe than my system you will find your F&D cycles will be very quick once the flow is tuned... and you will have a lot of flow redirected to spray bar.

I would also do away with the air tube, they are simply not needed in a well designed siphon.

I'm confused by oversized pump and "but no where near the flow your pump can deliver"

I think the standpipe should be larger. The smaller the drain I think the less power to the siphon effect, particularly as you are running a pump 8 times the volume needed to turn your FT over once an hour. If you're going to go CF I think you need to divert your water as above or make the standpipe much bigger.

I'm not sure why the right angle bend for the standpipe under the GB but a number of people think it useful. (I'm presuming that's the horizontal part you mention) I thought when I first read about it the guy wanted it to create movement in his FT so the wastes would be encouraged towards his central SLO. Maybe there are other reasons?

Something to consider on that note, is the heating effect you will get during summer - you don't have a lot of water in total volume there so you might need different rates of flow in Summer and Winter... or mighty tolerant fish.

He's saying your flow out of the GB, compared to the system he describes, will be faster but it still will not match what your pump is sending to the GB. He's comparing it to how much he was sending to his GB once he had his system tuned for the siphon to work properly and saying because of gravel and slightly bigger stand pipe, you will be sending more water to the GB but still need to have most of it diverted back to the FT.

Ok, if I keep my 50 gallon FT and my 400 GPH pump, the expensive items ^.^ what GB and plumbing would you recommend for better results? Again, I can't thank you all enough

I'd also like to note that my pump has an adjustable valve, wouldn't it pump 400 gph max but be much lower with the valve adjustment?

You need to find the flow/head chart for your pump.
if it has a flow of 400gph at 0 head, and has a max head of say 4 metres then at 4 metres you have 0 flow rate.
You need to find out with your head (and possibly take a bit of flow off for each 90 degree bend) what your actual flowrate is.
Of coarse i would also try to do a real world test, simply because those flowrates would be using the largest pipe the pump can take, use smaller and get a lower flowrate too.

It's an open question, depending on...

How many fish you are planning and what size.

How much you feed them.

How much O2 you need for a good DO amount.

Some options are, FT50, Pump at full throttle with diversion back into FT to aerate. GB25 and low stock numbers of fish.

Double up GB size for a 'normal' stocking level.

Add in external filters to increase stock levels.

Add filtering AND GB to go above 'normal' stock levels.

Add a sump to keep water levels constant in FT (also allows more fish if the water isn't dropping regularly to half tank.

Go CF to increase the amount of water held in the system.

Basically you are planning a small system - nothing wrong with that but you need to be aware such systems are less tolerant of changes - something going wrong could lose you your fish in a couple of hours or less. The more water in the system the more stable the temps are - you have thermal mass to absorb some of the changes.

Many people have IBC FT's - that's around 3 times as much water as in your entire system even with CF. The temps in the IBC can vary by 10ºC between night and day - your system will be much more sensitive to such effects.

Personally I would double at least the GB area, AND I would add filtering; although not strictly needed it gives an extra resilience to the system, plus hands you back fertiliser and nutrient-rich water.

I'd probably also add a sump but that's just my preference - to me it gives a more stable environment to the fish (which you also get on CF) you can aerate ST AND FT with your oversized pump - spray bar into FT (or venturi) and divert water back to spray (or venturi) in the ST. It also doubles the thermal mass in your system and if hidden from the sun, would be a source of coolth to keep temps down directly.

I also plan on getting fresh water mussels for my ST - don't know if you have them but they are excellent for cleaning up water - I thought with them I can add other species into the ST such as yabbies or prawns etc.

I see that alot about fresh water mussels.
Does anyone here actually have experience as to what they clean?
I have seen wild claims everywhere about them keeping the water "clean and clear".
i have ALWAYS used them in ponds ive made and have never had unclear water, however i have 100 (99 now) in my AP system (5400L) and they do not do a single thing to stop algae growing or water going green.

I imagine what they would be best at is keeping the system "healthy" and disease removal to a small extent.

Do you have an environment for them? I'm assuming you have the right type of mussels as river ones don't do so well in still water. But they require something to burrow into and most of us keep our AP systems free of debris. Maybe they need sand in the bottom?

I have sand in the bottom of the tank that they are in, i have been meaning to pull it out as i was adviced against it in my richgro thread thagt turned into a "fix my system" thread.

Type, im not sure, i bought them from Aquablue seafoods but thier site seems to be down right now.

Sorry... it was as plain as mud, should've written it better but was in a hurry.


Yep, what he said... except I wasn't talking about the flow out of the GB, that is what it is, I was concentrating on the flow into the GB needing to be faster.

Basically what I was trying to say is, because you have a larger dia' standpipe than what I had in mine, you will need more flow than I did to get your siphon working, but you will still not use anywhere near the full flow of your pump. You will have to divert the excess flow/pressure through a spray bar on your FT and put a valve in the line so you can adjust the inflow into the GB and tune the siphon.

As I said before, you have less gravel volume than I did, so your GB will fill quicker and you have a larger diameter standpipe which will require faster inflow into the GB to get the siphon working, so your F&D times will be much shorter than mine, which were 12 mins. If you went to an even larger standpipe dia' as someone suggested a few posts back, you will need to increase the inflow to the GB even more to get the siphon working properly and you will have very short, rapid filling F&D cycles only a few minutes apart. This can be a bad thing as it doesn't allow any solids to settle in the GB ,so they get continuously pumped around the system, which isn't good for the fish's gills.

In short, The flow has to be proportional to the width of the standpipe.