Need some help choosing a stock list

I tested my water today before my weekly water change. I only have test strips but here are my numbers.
GH=120
KH=120
PH=6.0
If these numbers seem off, I can try to take a sample somewhere to have it tested.

I am still gathering ideas as to what to put in this tank. Could I possibly do a pair of Angels and a pair of Discus then maybe some of the smaller cichlids such as rams?
 
I think I have found a variety/species that I would like to try. 'Lamprologus' stappersii. I have latched on to the species profile page on cichlid-forum. I like how you can select the group and subgroup and then view the species in your selection. Anyway, what do you think of my selection? After spending some time at the LFS watching a convict cichlid pair guarding their fry, I am even more interested in trying cichlids. My WCMM had plenty of fry for me but they rarely did anything with them after depositing the eggs.

That site says a PH of 8.6 I found a Dr. Wellfish ph tester in my supplies and tested my water again. The kit tops out at 7.6 and the water was off the chart. Do these test kits expire? Now I really need to get it properly tested. My tap water tested about the same color. The water in my 20 long tested right around 7. That tank has sand and a single fresh water flounder in it. I keep the salt in there somewhere between anti stress and brackish with freshwater aquarium salt. Does this lower the PH?
 
OK, one last question. I have been trying to find a used 90 gallon without any luck. The LFS has a 75 gallon kit for $175 with lids and a light. Another store has a 90, just the tank, for 235 and a 75, just the tank, for 135. Is the extra 3 inches in height worth it? I want to make a rock/shell dweller combo tank but I don't know how high the rock piles need to be.

I will be going to the river this weekend to collect my sand. It will actually be river rock with a max diameter of about 1/16 inch, everything that fits thru the holes in the colander. I am probably going to find some larger flat rocks while I am there too. Should look just like Lake Tanganyika except a little more colorful with the agates and granites that are in the river. I don't live too far from an ancient ocean bed should I try for some of that sandstone instead? You can look up the history of Coralville, Ia if you are interested.
 
OK, one last question. I have been trying to find a used 90 gallon without any luck. The LFS has a 75 gallon kit for $175 with lids and a light. Another store has a 90, just the tank, for 235 and a 75, just the tank, for 135.
It sounds like the 75 gallon kit is the best deal. It sounds like the price for the 90 gallon is pretty high. It should not be that much more than a 75 gallon tank.
 
I agree that the 75 kit is the better deal. I just don't know if 21 vs 24 in height is going to make or break my plans. They said that the 90 had thicker glass as well but I couldn't verify because they were still in boxes. Anyone have experience with Marineland tanks?
 
OK, I have decided to get the 75 instead of the 90. I went to the river this weekend and got 3-2 gallon buckets of small river rock/sand. The largest particle is about 4mm most of it is under 2mm. I went to the pet store and asked them to find 10 stappersii for me. So, I have the bottom dwellers for the tank. Now I need to find something for the rock pile. What rock dweller doesn't get too big and would go well with the staps?
 
I recently saw a picture of a fish while trolling the internet. I posted the pic here and found out that it was an Apistogramma cacatuoides. I am in love with this fish. 1-3" and awesome colors. Someone suggested apistos for my tank. I don't know why I didn't look into them. I think I had African blinders on or something. Strange thin is that every cichlid I have been drawn to in the fish stores have been South American. I am now leaning toward getting a nice sized group of these to put into my new 75g. As said before, I like to do biotope tanks. All my current plants are Asian, my driftwood is even Malaysian. I will have to find homes for my plants and WCMM but I really like the looks of these apistos. Can I get some suggestions on SA plants that the cacatuoides will like? Would a setup similar to an Angel or discus tank be appropriate for these guys? I read about them using coconut huts to spawn in. Is this natural or just easy?
 
OK, I went over to freshwateraquariumplants.com to look at plants. I bought from them in the past and they sent me some nice plants. Apparently biotopes are getting popular, they now have two biotope plans to give inspiration. One of them is a South American/ Amazon biotope. I like the plants that they picked. They also have some suggestions for fish and one of them is the Cockatoo cichlid that I have chosen. I am not too sure about the other fish on their list. Here is their suggestion.
Greenfire Tetra's 9-12; Marbled Hatchet Fish 7-9; Pencil Fish 9-12; or Cardinal Tetras 9-12; Ancistrus Teminiki 5-7; Otocinclus 5-7
I have always thought that the hatchet fish were funny looking. I am cool with the Greenfire and the Pencilfish. I have kept Otos in the past and love them for algae removal. The Bristle nose, I have not kept. Would these cause any problems with the Apistos when they start breeding? Could I swap them out for a bottom feeder like a cory? What do you guys think of their numbers for this tank? If I did the Greenfires and the Pencils and not the hatchets, could I get 15 of each and be good on those in a 75g? I want to get 6-8 of the Apistos.
 
I brought the 75g home yesterday and transfered the water, plants and fish from the 40. I am also running the two filters from the 40 for now as well. I don't have the substrate in there so most of my snails are gone. I hope that the four WCMM are enough to mini cycle the tank after the change. My next step is to get the fluorite or Eco-Complete to go under the substrate for the plants. I sifted the sand that I collected again. This time I put it thru a wire strainer. It is now small gravel with no sand. Smallest particle is about 1mm and largest is about 4mm. Once I get the substrate, I will let is sit for a week or so and then order my plants.

I saw some hatchet fish at the LFS and I have to admit that they may be kinda cool in this tall tank. I may have to consider them for the tank after all. After the substrate and plants are in, which fish should I add first? I plan to put them in one species at a time with a week in between.
 
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