Redtailed Shark with Mbunas

Question
Hi,I have 30 gallon tank set up since 1st of June.
I have also Redtail Shark since and used to be just two Mbunas "Yellow Lab" and " Acei Cichlid",.the Yellow Lab has been very territorial by himself in the tank so after resarch I added three more Mbunas last week.
It stop the agression in the tank and they are very attentive and peacefull but I have desided to change water every day about 5 gallons .Ammonia levels are way to high .
Its been 5 days I have been changing water . Now level is 2.0 ppm.I put Stress coat and alot of Prime in the new water also .I am holding the salt for now .But can I add 1tablespoon full to every 5 gallons after I finish one more change?
Now should I keep on changing untill ammonia reads 0 or should I now wait untill another week to change it?I don't mind doing the water changes every day its not that hard since only 5 gallons.And if its healthy for them to have water changed everyday I would do it. Those Mbunas are very good eater and poop alot also .What do you think?
My Nitrite level are between 0-.5ppm and Nitrate is 20 now . Ph level was high also like 8.5 but today back to 7.8.  Most main reason to change water is this,
My Redtail Shark tells me they have not so healthy water by burned looking skin and fin. And he wasn't eating before .Now I think he feels better and looks better .  

Answer
Lucy,
It's OK to keep up with the water changes. It will help the ammonia to drop.
If you add salt it is OK, but as you do a water change, only replace the salt you take out.
So, after a 5 gallon water change, put back one tablespoon salt. The redtail shark will not live long in the salt tank though. He shouldn't be in with Mbuna's.
Last thing.
If you can find bio spira in the pet store, buy it. It will fix you water problems right away. MUCH BETTER than Prime