This may be your problem! I looked up the cat litter you used as substrate and it appears to have added chemicals to control odor:
Premium Clay Cat Litter
For pet owners that demands the best, there's Special Kitty Premium Clay Cat Litter. Its odor control system traps odors while releasing a pleasant fragrance that keeps your cat's litter box smelling fresh and clean.
I'm betting that is what is making your parameters wonky. I've never been huge on cat litter as a substrate simply due to not knowing what kind of crap they put in it other than clay. If you are looking for a super cheap substrate that works, look for Turface ProLeague. Its a fired clay substrate but it's totally inert and has a high CEC so it soaks up ferts and holds them well. I used it on my 55 gallon and had great plant growth when combining it with Osmocote.
Pro League® Calcined Clay | Turface Athletics
Find a Distributor | Turface Athletics
You could be right, although I did buy the unscented kind and the exact brand that people recommend if you want to go the clay route. It's supposed to be pure clay without additives. It's something I had laying around the house from my 1st planted aquarium attempt So I used it. I plan to test it today in a bucket of water. Testing the water before and after I add the kitty litter. Money is not a huge issue since the tank is so small. I don't want to drag it out of the aquarium if I don't have to at this point. But I will if I need to.
BUT, I was planning on getting the rest of my plants this weekend and draining most of the water to have better control while planting them. So... this would be as good of time as any to change it.
I think I prefer the KISS method with Neos....
Doesn't matter if it's play sand, pool filter sand, media blasting sand... just, sand! And as cheap as $4-$8 for 50 lbs!!!
I like the look of sand as well. But do plants grow well in it?
Last edited by lahornby; 04-20-2017 at 06:49 PM.
Reason: To much quote