I've kept African Cichlids myself. As well as Oscars.
As long as the 7 Cichlids you have are of the Smaller Variety Number wise to your Tank Size should be fine.
Average Tank Temp for a Cichlid tank Should be approx at Min 76 degrees F, Prefereed is 78 to 82 give or take a degree, when dealing with these fish 1 degree higher is better then Lower, provided it's not too extreme...
The highest it should be allowed to go is No More then 86 degrees F.
The Ph of 7.6 is O K but Could stand to be maybe a little Higher. between 7.8 and 8.0 is where I keep them.
A little Tid Bit is that Cichlids like their Water to be a little bit on the Hard Side.
If your water where you live is a little On the Soft Side or even if it's Neutral around 7.0, You can use a couple of pieces of Limestone, to HELP Buffer your waters Ph, this is what I use in my tanks.
It helps to keep the Ph right at the preferred Range of 7.8 to 8.0, even 8.2 won't Hurt providing it's not a Rapid change.
I don't like to use Chems as if your not real careful you can change it to rapidly which will/can Spell Death for your Fish.
As far as them hanging around the Filter Intake, I can't answer.
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But do you have any Rocks setup into Cave like formations? For them to Hide in and claim territory?
Cichlids are Very territorial.
This maybe the reason WHY they are hanging close by the intake, thats where they feel Safest
Which is another thing thats good about using Limestone, it serves a dual purpose. Caves for Living and Buffers the Ph for your Beloved Fish.
A Few Plastic plants of Various Sizes spread across the Tank also Helps.
I don't really know if this will Help Much, But this is what it Sounds like to me Maybe the problem
If I can HELP anymore please let me know.
And {PLEASE KEEP ME POSTED} daddyfish