[Lupin]

Not sure about the blue one but looks like Pseudotropheus kenyi to me. The yellow one is a Yellow Lab. Yellow labs have a rather mellow attitude.

Your 'algae eater' is a common plec. Not exactly excellent at consuming algae. They will grow to 16 inches.

 

[Lupin]

Both are African cichlids. Don't use pH up. Such chemicals can cause pH swings killing your fish. Consider using buffers or calcerous rocks instead. You'll need to know your KH(carbonate hardness) and GH(general hardness). I'd just add established filter media from your lfs instead of those 'bacteria' stuff. Yes, a daily water change of 10% should help.

 

[Lupin]

Established filter media are the ones that have been colonized by bacteria. They help speed up cycling of your tank. Your GH and KH appear to be soft but is just enough to prevent any possible pH crash.
Have a read with this link.
Anything lower than 4 dH will result to pH crash.

Your lfs should have those rocks. Limestones are one of those. If not, just use crushed oyster shells and place them in your filter.

Do not add salt in your tank. They are totally unnecessary. What kind of salt is it anyway?