This has been discussed quite a bit since the Filter Guys went out of business recently. We're all looking around for new sources for filter cartridges, and learning about what we need to order, sediment pre-filters, etc.
It's a lot of info, and it's a little bit complicated, and the whole thing is difficult reading here on MFK because the discussions are product recommendations, build threads for new filter systems, and some discussions of chemistry and water parameters, all mixed together in different threads over the last 6 months.
I'm gonna keep it real simple, and just throw out a recommendation. This is VERY close to the chlorine/chloramine filter I've been running for years now from the Filter Guys.
https://www.amazon.com/Fortress-Fil...=2025&creative=165953&creativeASIN=B00HVGV7TO
There are replacement cartridges for this all over the internet. Just remember 2 things.
1. You must use a sediment filter inline to remove sediment from water that is going into the next 2 housings that hold your activated carbon filter cartridges.
2. If you have chloramines in your water supply (very likely that you do), use an "activated carbon filter" that "removes chlorine and chloramines".
Hope this helps. Looking forward to hearing what everyone else has found out.
Here are some links to recent discussions about all this....
https://www.monsterfishkeepers.com/forums/threads/autodrip-advice.693144/#post-7812358
https://www.monsterfishkeepers.com/...appen-to-the-filter-guys.687826/#post-7752337
https://www.monsterfishkeepers.com/forums/threads/filterguys-replacement.691496/#post-7794143