Although not related to fishing....it is related to aquariums and fish.
I'm sure there's a bunch of people out there who knows what Kickstarter does but for those who don't, it's pretty much a web site that helps people raise funds for a particular goals/tasks. So, if you have a great idea for an invention but often don't have to funds to pursue it, then you can put it up on Kickstarter and show people your idea and if they like it, they can help the cause by donating money to the inventor. There's been many great items which have all started through Kickstarter or sites like it. Heck, if you have fishing lures or equipment that you want to make/invent and need some extra money to help fund the project this would work.
Anyways, long story short, this one will be great for those freshwater plant keepers.
https://www.kickstarter.com/projects/4612189/oco-the-worlds-first-co2-meter-for-aquariumsThere's a meter and also a controller. How this differs from other CO2 controllers is that it doesn't measure the pH and give you an estimate of CO2, it actually measures the CO2 so it's more accurate. Anyways, though you guys may be interested and if you donate, you also get a few things..... take a look at the link yourself.
Cheers