African cichlid staying at the bottom of the tank

[florist]

I recall mollies requiring hard water, whereas cichlids need an even higher pH, which is something to consider, given the mix of fish in my tank.

[slayr]

I'm starting to think those fish didn't just die off from a minor issue. Nitrites and ammonia, they don't just magically disappear within a few hours. It's likely they were suffering from ammonia poisoning, and that's what ultimately took them out.

I also read that mollies need hard water and cichlids need even higher pH. I'm starting to think that's my issue. I've been having a hard time keeping my cichlids alive. I've lost a bunch of them already. I'm going to call the city to get the parameters of my tap water and see if that's the problem.

[slayr]

I just did a 50% water change, scrubbed the sand and all the decorations in the tank, and cleaned everything else I could reach. Now one of my yellow labs is swimming around in the middle of the tank like normal, which is a big relief. I'm not sure about the other one, though - he's still sitting at the bottom and I'm not sure if he's too far gone.

I was reading online and it said that if you don't change the carbon filter pads, they can actually start pushing chemicals back into the tank. So I put new ones in, but I kept my bio wheel and filter pad the same to keep the good bacteria going. After the water change, my parameters are looking like this:

Ammonia is high, but I just did a water change and my tap water has ammonia in it, so that's not surprising. I added Prime to the new water before putting it in the tank, so that should help neutralize it.