Pale Acei cichilds

[A-N-I]

About 2 months ago, when I first set up my tank, I bought two yellow tailed acei juvenile cichilds. They've always been a super pale purple. At night they turn almost black. And about a week ago, I decided I didn't want them so I gave to my friend. (She has a 55 gallon, and she already owned two Acei) And as soon as she put them in her tank, they turned dark purple, and remained dark purple. Today, I decided I missed my little purple buggers so I got them back. And now, they are still a pale purple. Why do they remain a pale purple in my tank, but were dark purple in my friend's tank?
Is this normal? Or is something wrong with my tank? All my other fish seem to be fine.
My acei cichilds are currently about 2.5 inches.

 

[TMRC Exotics]

First, list your tank size, current stock and water parameters. Like many cichlids an aceis color shows how the fish is, a pale color could indicate anything from fear of predation to improper water parameters. More info is needed. For reference mine stays a nice hearty dark blue/purple with a nice pop of bright yellow fins

 

[A-N-I]

I have a 30 gallon, current stock (all juvenile fish), 2 angelfish (I plan on getting another tank so I can separate them when they get older) 2 electric yellow cichilds, the 2 acei, 2 panda corys, 2 green corys and 1 upside down catfish.
The two acei, I don't think they're fearful of predation because no one picks of them. All of my fish are about the same size (except the panda corys, they're tiny)
My tank's temperature is 75-80 F.
I just checked the ph level and it is around 6-6.5.
I have lots of hiding places in my tank, half the time I have to search for my fish.
Right now, my acei are a pale purple with light yellow fins. Shortly after I first posted in the thread, they went to a nice purple and their fins were nice and yellow. Could it be the lighting? I have them in my living room across from a big bay window. I have curtains covering them, but it's still fairly bright.
And I feed them TetraMin Tropical flakes every morning and bloodworms 2 or 3 times a week. (The corys get shrimp pellets and algae wafers.)

 

[TMRC Exotics]

The pH is low. 7.8 is ideal for African cichlids. There are stocking issues there as well. You definitely should separate the angels from the Africans. I don't see the corys working long term either with the Africans though they may.

Why is the pH so low? Is this what your tap water runs or is there something in the tank buffering it?

Edit to add: 30 gallons is to small for African cichlids. The yellow labs and the acei need a 55 gallon minimum. 40 breeder being the absolute minimum.

 

[A-N-I]

Okay, thanks for the advice.
As to why the ph is low, I have no clue. (novice)
I saw some "ph Up" in the pet store, so maybe I will buy that.

 

[TMRC Exotics]

Most people advice against using chemicals to alter pH as you can get swings in pH where stability is usually more important than meeting an exact number. Test your tap water straight out of the faucet, then let some sit 24 hours in a cup and test that. Report both of those findings.