New 55 gallon set up- compatibility

Question
QUESTION: You have been so helpful i decided i need more info. After lots of research i am still confused. I recently got a deal i couldn't pass up. A 55 gallon tank stand and filter for $50. As money is tight i figured this was my chance to get a bigger tank and possibly get the tank i have been wanting for the last couple of years. I love Frontosas and i realize it is not ideal a 55 gallon. That being said from what i understand i should keep it with 1 male and 3 females. Now do you think i can do this in a 55 gallon if they are young and eventually move them to a larger tank when i can save up? That is my first ?. Also i have been real confused with substrate choices. I have thought after being told not to do sand, can i do sand and use a small divider mix it with crushed coral? or is that over shooting.
If not should i use crushed coral or shells...i saw some tanks that look like its coral or thick sand that is black and white..do you know what that is?  as always your help is very much appreciated.
also one more quick thing...diy backgrounds with styrofoam and cement..dangerous or ok?

ANSWER: I would not put styrofoam in a tank... especially with cichlids... they will most likely tear it apart.  I think the mix of one male and three females is great for the 55 gallon.  You eventually will want to go larger especially if they start to breed.  100 Gallons or more would be ideal and you can find really great deal on used tanks on places like www.craigslist.com.  I recently bought a 125 gallon tank for $100 with stand.  As for the substrate... what do you want the substrate to do for your tank?  do you want it to raise or lower pH??? or do you want a specific look???   dave

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QUESTION: Yea i actually picked up my 55 gallon with stand and emperor filter and hood for $50.  That is what got me here. Well I guess the look and the ph would be my concerns for the substrate. If i use all crushed coral or something similar would that make the ph to high. My water is about 7.8 naturally (or maybe with a bit of aquarium salt, dont know if that affects it) I was under the impression that for fronts you want it about 8.2-.4. I know they will adjust but i just want for once to have a successfull tank with no deaths. Speaking of if i may also ask you . My goldfish ( i believe a pearlscale about 2.5-3.5 icnhes lives in a corner tank with a larger and smaller ryukin. Three times in the last week he has gotten stuck to the filter and has been sluggish. I changed the water added salt and water treatment with the aloe etc.. He still comes to feed and swims around a little but definitely not as active... What can i do to make sure he survives.
Back to the other tank..what can i put with the fronts or should i leave them alone in there?  
The styrofoam i was referring to is a do it yourself project i read about here is an example..  http://www.cichlid-forum.com/articles/diy_aquarium_background.php
the foam would be covered by cement..any thoughts?
as always thank you

Answer
The most important thing is to meashre the current pH to the pH of the tank the Frontosa's are in now.  If the difference is less then .5 then you are fine.  You can mix black gravel with coral gravel to get the look you want without too much issue.  Driftwood in the tank will help to lower the pH if the coral gravel raises it too much.  7.8 pH is good for cichlids. That is an interesting project... the background.  You can achieve the same detail with a sponge background that is actually a filter...  dave