Very difficult to justify the expense compared to tanked C02.
I was also not crazy about the low voltage electrolytic process in my systems. Low or not I thought the current was significant enough to agitate mucous membranes on fish. If anyone doubts that, they can purchase a 10 pack of 9V batteries and lick them till they're out of juice. If your tongue still fits in your mouth go apologize to the fish !
At an average cost of $40.00 per replacement block you can purchase quite a bit of Co2... never mind the fact that the product is a retail oddity that commands a premium price.
The product does in fact work as stated unless of course your system is grounded then you may have a problem !
I believe the Elite electrolytic units commonly sell on ebay for around $50.00 HTH. Prof M