The most cost effective way to tell would be with the Aquachek test strips for iron and copper. Their iron test strips are just a bit over $20 for a bottle of 25. Don't know how much the copper strips are. You just need to know if they are present. You don't really need a lot of precision. The Taylor kit that tests for them is about $85. It's the K-1264 and it tests for copper and iron. LaMotte makes the EC-67 kit that tests copper and iron but I don't know the price or where you can get it.