Aquaponics Most Frequently Asked Questions

Question: How is Dura Skrim 20 WW  constructed?

Answer:  Dura-Skrim 20WW is built using linear low density polyethylene.

HDPE (High Density Polyethylene) has minimal branching of its’ polymer chains. Because it is denser it is more rigid and less permeable then the LDPE.  It has a density of 0.941-0.965 g/cm3.

LLDPE (Linear Low Density Polyethylene) has a significant numbers of short branches. Because it has shorter and more branches its’ chains are able slide against each other upon elongation without becoming entangled like LPDE which has long branching chains that would get caught on each other. This gives LLDPE higher tensile strength and higher impact and puncture resistance than the LDPE. It has a density of 0.91-0.94 g/cm3.

Question:  Why would a special liner be needed for aquaponics and hydroponic systems?

Answer:  This has so much to do with system safety.  When you use an unknown liner, meaning that you do not know where it comes from then you risk the chance of using a liner that my leech out “bad” things into the water.  It is not as simple as just smelling the liner, though the nose test is something I like to perform every time look at a new liner.  Does it smell?  If it does, what are you smelling?  Have you ever taken a sealed shower curtain, opened it up and been overwhelmed by the chemical smell?  Most likely the film is off gassing.

By using a film that you know to be 100% virgin resin, you know that the film is not recycled and has not been exposed or mixed with potentially dangerous chemicals.   Please note that I am not saying that recycled material is bad, it is just not optimal in this type of system.

If you put your time, blood sweat and tears into building your system, use the best that you can use. 

Please also take into account how the film is sealed, is it sealed/seamed using heat or sonic welding (in my opinion the best way to seam or seal a film.  Basically no adhesives are used in the process.  They use the same material that your liner is made of. Both Dura Skrim 20 WW is seamed in this manner. 

Question: Please explain organic certification.


Answer:  Please click here to read about it in our blog section.

Question:  Is either DS20WW food grade?

Answer: No it is not food grade, it is fish safe.  In order to get a food grade rating it must be produced in a plant that is certified.  If someone tells you that Dura Skrim 20 WW is food grade, please provide us with the verifiable certificate.  We will give you a free roll of Dura Skrim 20 WW 6 foot x 25 feet.  (After all these years we have not had one taker!)

Question:  When looking for a liner what should I look for? 

Answer: It really depends on they type of system you are putting in, budget and what you want from a liner?  But lets stay with the basics:

  • Virgin polyethylene,
  • seamed using heat or sonic welding (no glues, unless you can certify that it is fish safe glue)
  • Fish safe liner.  This is critical, if its safe for fish it most likely will be safe for you, (you’re not drinking the water are you?)
  • strength in the film, puncture strength, stretch ability, impact
  • how does it wear,  imagine your system and all the moving parts, will it wear through your film? 
  • Ultra violet stabilized films, this may be important if you grow outdoors and not in a greenhouse.

Question:  Can I used this for both my grow beds and my fish tank?

Answer:  Yes you can,  the DS20 has some building limitation because of the way we fabricate it.

Question:  Do you have something Food Grade?

Answer:  Yes, we do!  we are in the process of getting ready to roll it  out. It is food safe rated and is amazing.  This is by far our best liner out there! I call it our cadillac of liners!  Truly amazing strong and safe liners!

Biomedia for Aquaponics Systems

Question:  Is there a biomedia for my aquaponics system that is safe for the fish?  I understand that certain plastic sheeting products off gas thus killing fish. Do you have a biomedia for this purpose?

Answer:  Enkamat 7010 is the answer for your biomedia need.  This product has been used in filtration systems for the past 15 years for both aquariums and aquaculture. It has been used in the commercial fish industry.  Enkamat stops bacteria from reentering the tank by providing a bed for bacteria to rest on.  The open weave offers a safe haven for fish eggs to rest until they are ready to hatch.  Enkamat 7010 has also been used as a filter for pond pumps.  Call Global Plastic Sheeting, and ask for Ken.

Aquaponics Questions and Answers...Ken's Corner!

Below is a question and answer session between Ken Aguilar, Manager of the Agricultural Division at GPS and a customer.

aquaponics helpAquaponics Customer:  Ken I have a problem with yellow leafs on my cucumber plants.  What do you think it is?

 Ken:  It seem to be a disease, powdery mildew, if you turn the leaves over and see  white or gray powder, it is that disease most of the times appear during warm weather and high humidity

Aquaponics Customer:  No powder or mildew. Just yellow  It's in an aquaponics system, well established.

Ken:  Is that the back of the leaf? If the pH of the water is too low, below 6, it could be a deficiency of Manganese or Magnesium.  It doesn't look to be a problem for salinity (High EC, 3 or higher)

Aquaponics Customer:  I believe it is humidity. Ph is @7 so that’s not the issue.

 Ken:   Tell me about your greenhouse?  Are the leaves getting wet from drip coming off the ceiling of your greenhouse?,  It could be that the leaves are getting damaged by the water acting line a magnifying glass on the droplets.

Aquaponics Customer:  LOL yes, it is like a rain forest in there, very wet, almost like rain.

 Ken:Okay, then lets do this, do you have any extra sheets of plastic?  I want you to create a small cover over a few plants, keep it from getting wet and lets do a comparison and see if the yellowing goes away.   Also lets increase your air flow, humidity is good but it can also be bad in some circumstances, lets lower your overall humidity and keep the plants dry.    I don’t think it is a disease.  Also since it is aquaponic based, lets see if we can correct this issue mechanically rather than chemically, to help your fish out!

If it is the water droplets, that’s an easy fix…

 Ken:  The technicians from ENZA ZADEN Seeds say it is mildew.