Backyard Aquaponics
A place to discuss aquaponics

i have a 2" drain, so ill have a 4" autosiphon
12" deep media beds.

so i think ill need a 5 or 6" gravel guard?

what are some materials you guys use for a gravel guard this size?
where can I get them?

thank you!

Well PVC pipe is the typical one, but you could scrounge anything that size that is food-safe and rigid enough like food containers etc.

Wow I didn't think that PVC came in sizes that big. All I saw at Home Depot was black drainage pipe.

What is the rule of thumb, 1" bigger or 2"?

I used the rule to double the size each step.

An 8" gravel guard? Yikes. Really regretting the 2" drain pipes now.

While at home despot, go to the fencing section, not sword fighting, and pickup some plastic hardware netting. It makes for a great media guard, and can be customized to whatever diameter you need. Plus you will use it to net off your fishtank to keep kids and critters out. As far as sizing your guard, you just need to make sure your bell can fit, and also your hand when the bell is removed.

Avoid the black plumbing pipe. It floats which has caused me problems. I eventually upgraded to 6"PVC. 1/4 inch plastic hardware netting would probably work well. It is made out of PVC. And its usefull in so many places around the garden.

How much do you need? I can get you some pvc but you"ll have to drive to the NW side if you want it.


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Thanks for all the replies. I went and bought that black hardware mesh to use. But I started a new thread about whether I should use a smaller diameter stand pipe. I'm starting to think it might be too big to function properly.

Hiya rjin, I use a 1" stand pipe for my 100G gb with a 3" mg draining into 3" drain. Put up a photo of your set up and I'm sure someone will have an idea of how you can step it down to suit your 2" drain. I have a 1"-2" reducer that fits snuggly into a 2" basin drain on the 1" stand pipe.
Hope this helps.

Ok. Here's a growbed

The whole system

Your standpipe definitely doesn't need to be that big. 1 inch should work just fine. I think you will have problems getting your siphon to start with that large of pipe. A reducer can be used to fit a 1 inch pipe into your 2 in drain.

Agreed... 25mm standpipe is the largest would ever need in an IBC grow bed. I have a 20mm in mine and have 16-17 minute F&D cycles.

I would leave the existing 2" standpipe as a back-up overflow and install a new 25mm standpipe. Just pull the existing one up about a cm higher than you're going to set the level for your new standpipe, then put a gravel guard around it.

For the new siphon with a 25mm standpipe I would use a bell diameter of about 65-80mm PVC, then a 100mm diameter gravel guard, unless you have really big hands, then maybe go for a 150mm gravel guard. In saying that, other than many years ago when I first started and was experimenting with different siphons designs, once they are installed, I've never had to remove/replace a siphon standpipe.