Backyard Aquaponics
A place to discuss aquaponics

Hello all,

I am new on this forum and I am trying to come up with a design for an aquaponics system. I currently have an aeroponics system I built myself out of a storage tote. I'm thinking about using cation and anion exchange resins to assist in filtering and regulating pH in an aquaponics system. I understand that I need to be very careful in deciding what resins to use as they may pick up nutrients from the water that I want to get to the plants/fish. I intend to use a cation exchange resin for the plants to keep the pH at about 6 and anion exchange resins in the return line to the fish to keep the pH at about 8. Does anyone know anything about using ion exchange resins in aquaponics?

Thanks!

Take this answer with a grain of salt because I haven't tried it -

The closest I've seen anyone here come to doing this is people who use reverse osmosis to treat their top up water and then add whatever ions they need back in once it's added to the system.

If you're doing this for a learning experience on a small system then OK, I think it might be worthwhile. If you're doing this on a larger system or with the thought that it makes sense to run a system this way then I'll say that I really, really doubt that it makes sense.

I'm pretty sure this wouldn't work because it would require lots of resin to maintain chemistry. Also, the plants need nutrients as well as pH. I think the resin would have to be very special to maintain proper balance of nutrients for the plants and, for example, not filter out particular nutrients. Ion exchange may be good to filter out something bad in the makeup water.

Yeah, that's what I was trying to figure out. I use RO water for my hydroponics system because the buildup of calcium carbonate from my tap water was causing issues for my plants. From what I've read about ion exchange resins, I think you're right that it would have to be very specialized for my specific setup for it to work properly and I simply don't have the chemistry knowledge I'd need to manufacture something like that. I was most worried about how they might affect the nutrients that get to the plants but anion exchange for the fish seems like it would be very feasible to ensure none of the bad stuff that the plants may not handle gets to them. However, it may require an additional pump to get the right pressure through the column to make sure flooding doesn't occur in the flood tray. I haven't done aquaponics yet but I really want to and I'm trying to come up with ideas for how to make it as automated as possible. Thank you for your replies and I hope to get more feedback on this topic to see if anyone has done something like this with reasonable success. I was reading about a specific resin (Amberlite CG-50) that someone had used in a hydroponics system to maintain pH and was successful in doing so. I haven't read anything related to its success in aquaponics though.