Siphon Guard

[Stephanie Bader]

As anyone ever used a siphon guard like this one? or made one like it? And how did you do it? Any pro's or cons to using one like this?

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=251121183846

[TCLynx]

I'm a big fan of do a bit of your own research and then make your own choices.

Don't let fear of plastic stop you from doing aquaponics.  Just try to make your decisions as informed as possible.

There are negative impacts or issues with just about any material out there.  (The issues or impacts could be with leaching or the manufacturing or cost or the disposal or just that some materials won't last long or leak and have to be replaced too often for those who would have us all using bamboo as pipes.)

John Cubit said:

Yeah it is used as a whitening agent in breads and for flour and the government recommends avoid bromide breads due to allergy reactions but ok for use in flour processing. It is the reactant for the foam used in the PVC core.  MMMM bromide by-products..

I think this sums it up:

The principal use of azodicarbonamide is in the production of foamed plastics as an additive. The thermal decomposition of azodicarbonamide results in the evolution of nitrogen, carbon monoxide, carbon dioxide, and ammonia gases, which are trapped in the polymer as bubbles to form a foamed article. Common examples of this application are window and door gaskets, padded floor mats, gym/exercise mats, shoe soles, etc.

But yet it is listed as a food additive.

Bob Campbell said:

I did a little research to find out about DWV foam core PVC.   Azobiscarbonamide is used to create the foam interior.

This is a chemical that is also used in flour.  I'm no chemist but it does not sound too dangerous.

TCLynx said:

Because as far as I know no one seems able to get an answer about what the "foam core" is and how safe it is in our food.  Therefore I generally chose the solid pipes.  (the thinwall suff is easier to cut anyway.)

Bob Campbell said:

Why not DWV Foam Core?

TCLynx said:

If you can cut slits in large pipe (not foam core) with a saw, that is probably the less costly option.

Gravel Guards

I don't think 3" pipe is big enough for most gravel guards (might be ok for me with tiny hands but if you can't carry the roll of duct tape on your arm, then a 3" gravel guard is probably too small for you.) I like my gravel guards in the 4-6 inch range.

Now I have used the black poly corrugated drainage pipe as gravel guards before.  I get the perforated ones but they require more than just the perforations that they come with so I take a saw and cut more length wise cuts in them.  Set the blade so it won't cut more than just the outer part of the corrugation.  It is pretty quick and they don't cost that much and being black they are already more UV stable than PVC.  They are still a little on the small side but better than 3" pipe gravel guards.

[John Cubit]

Agree..5 second rule!

I would love to go to a larger guard.  But my current bed is only 10 gallon and 6" would not have made a grow bed just a tote with a hole.  Seeing as the bell is 2" and the downspout is all 3/4", 3" still leaves me room to pull the bell, clean etc..and leave me 75% of my grow bed to grow.  Deff.  when I can prove to the wife I can be a "big boy" AP then I will get my 6'x4'x13" gb in the family room or....in the new "out building"....wish wish wish!

TCLynx said:

I'm a big fan of do a bit of your own research and then make your own choices.

Don't let fear of plastic stop you from doing aquaponics.  Just try to make your decisions as informed as possible.

There are negative impacts or issues with just about any material out there.  (The issues or impacts could be with leaching or the manufacturing or cost or the disposal or just that some materials won't last long or leak and have to be replaced too often for those who would have us all using bamboo as pipes.)

John Cubit said:

Yeah it is used as a whitening agent in breads and for flour and the government recommends avoid bromide breads due to allergy reactions but ok for use in flour processing. It is the reactant for the foam used in the PVC core.  MMMM bromide by-products..

I think this sums it up:

The principal use of azodicarbonamide is in the production of foamed plastics as an additive. The thermal decomposition of azodicarbonamide results in the evolution of nitrogen, carbon monoxide, carbon dioxide, and ammonia gases, which are trapped in the polymer as bubbles to form a foamed article. Common examples of this application are window and door gaskets, padded floor mats, gym/exercise mats, shoe soles, etc.

But yet it is listed as a food additive.

Bob Campbell said:

I did a little research to find out about DWV foam core PVC.   Azobiscarbonamide is used to create the foam interior.

This is a chemical that is also used in flour.  I'm no chemist but it does not sound too dangerous.

TCLynx said:

Because as far as I know no one seems able to get an answer about what the "foam core" is and how safe it is in our food.  Therefore I generally chose the solid pipes.  (the thinwall suff is easier to cut anyway.)

Bob Campbell said:

Why not DWV Foam Core?

TCLynx said:

If you can cut slits in large pipe (not foam core) with a saw, that is probably the less costly option.

Gravel Guards

I don't think 3" pipe is big enough for most gravel guards (might be ok for me with tiny hands but if you can't carry the roll of duct tape on your arm, then a 3" gravel guard is probably too small for you.) I like my gravel guards in the 4-6 inch range.

Now I have used the black poly corrugated drainage pipe as gravel guards before.  I get the perforated ones but they require more than just the perforations that they come with so I take a saw and cut more length wise cuts in them.  Set the blade so it won't cut more than just the outer part of the corrugation.  It is pretty quick and they don't cost that much and being black they are already more UV stable than PVC.  They are still a little on the small side but better than 3" pipe gravel guards.

[Jim Fisk]

I did a quick scan of the replies here and did not see anyone comment on one thing I did not like (among many including the ridiculous $) is the ability or in this case inability to be able to rotate the screen in order to cut off roots down the road. Can't do that if it is glued on. I also saw this ad on Ebay and had to laugh. You have to think down the road and this screen WILL become a root clogged nightmare in my opinion. And then what? Not to mention it is way too weak.

[Rob Torcellini]

I said it earlier....around the 2nd post.  

[Jim Fisk]

So you're saying that my 2 cents worth wasn't even worth that much Drove 4800 miles in the last 7 days so pay no attention. Need to recoup.

[Rob Torcellini]

Sometimes it's good to state the facts twice...just like getting a second opinion!

[TCLynx]

I have used those screens, at least the 3" ones.

Since many of my beds are 24" deep and plumbed out the side of the bed, there is no rotating of the screens no matter what you use since the plumbing wouldn't allow it.  And with heavy gravel it isn't as easy to rotate any screen.

I wouldn't glue down gravel guards in any case though.

As to the root clogging.  With regular veggies, I've not found the screens to clog up,  There are just so many holes in them you would actually have to have the bed pretty much totally root clogged to have clogged up the whole screen.  That said, I've grown some NOT normal stuff that can cause root issues through such screens, but those things would cause issues through a PVC pipe with holes or slits too.  For instance bamboo or Lufa or Mint.

So it all really comes down to your situation.  Those mesh tubes are kinda silly expensive and the big ones are not sturdy enough for heavy gravel or deep beds.  Do you have access to a Chop saw you can use to cut lots of slits in a large pvc pipe?  Can you get large pvc pipe in appropriate lengths for your projects?  If you have to buy a 20' stick of 6" pvc at retail prices (probably over $2.50 per foot) and then pay some one $10 an hour to drill the holes because you don't have a saw big enough or with the right kind of blades just for one or two gravel guards.  Then one of those 40" mesh tubes starts looking more attractive (aquatic eco systems sells them in 40" lengths I think.)  If you can get a scrap piece of pvc pipe for cheap and have the tools needed to do the job efficiently then definitely make your own.

I actually like those tubes for making large pump intake grates or specialty plumbing drain screens for tanks with small fish.  For troughs with leaves and debris though, need bigger grates to keep from clogging up.