Please help - mbuna cichlids black spots

[Gord ward]

If anybody can lend some advice here it would be greatly appreciated. 
 

I have a 75 gallon tank with a few different types of mbuna.  Moved to a new temporary house while mine is being built and the house has water softened by softening salt.( this can’t be avoided without adding a bypass before the softener).  For the most part things have been fine.   In other tanks my plans are growing and I have a school of 20 cardinals with some guppies in a 30 gallon as well as another 30 with babies from A few of the mbuna. I started to notice these black spots on many of the their faces head and belly areas.  The water out of the tap is almost 0 gh but has 250 kh.  I add 1 teaspoon of Epson salts for every five gallons of water and that brings me up to just over 100 gh. The tank has full gravel of crushed coral 

 

ph 8.6

gh 100

Kh 250

no Amonia 

no nitrite 

10-15 nitrate 

temp is 80 

I sent a pic of the whole tank since I don’t know  species by name. I also get this dark algae all of my rocks and gravel if anybody knows what type of algae it is it would be helpful.   I also included a close up of it.  

[Brymac1]

This looks like a case of flukes. I would treat the tank with praziquantel.

[Colu]

 The black spots could be caused by digenetic metacercaria I would recommend treating with praziquantel in food 

[Gord ward]

Hey guys just an update.  I’m in Canada so we don’t have any good meds.  I got something called supratect. I dosed them and soaked some food and In48 hours they are almost totally gone.  It’s some all natural stuff that can’t even be advertised as medicine up here but man my fish are popping off. I dosed all my tanks and I have never seen my fish this happy.