My Freshwater Tank & fish Problems

Question
Richard,  I have a 150 Gal fresh water tank, I purchased at a local fish store.  The lady is very unhelpful, and ubnoxious.  I have purchased several fish, and they all seem to die within 1-2 weeks.  Always after the 24-72 day period to return the fish if they have prob for replacement.  The amonia levels are fine, and we are regularly changing the water.  They get spots on them after a week, and then they die within a few days after that.  We just cleaned out the tank, put fresh water in, and tablets to stabalize the water, then went and spent 200 on new fish 2 wks ago.  All but 2 algea eaters, and 5 frogs have died.  I'm somewhat dissapointed, and ready to just get rid of the whole thing cause 1: I can't keep watching them die, and 2: I can't afford to keep buying 200-300 $'s worth of fish every month.  If you could help me out that would be awesome.  I would have to have $1,200+ go down the drain before finding out if there is something that I can do to fix this.  I tried talking to the lady at the pet store, and all she seems to do is tell me that well maybe you aren't a fish person, or wants to sell me $100's of dollars more in product that I honestly don't think is really needed.  I didn't have this much problem with the betta I had, or the 150 gal tank at work.  Hope you can help.  
Thank you kindly,
Tausha

Answer
Hi Tausha

Well it sounds like you didn't let your tank complete the cycle process. This takes 4-6 weeks after you setup your new tank. When you setup a new tank, you can only add about 1 inch of fish per 10 gallons of water while the tank is cycling. Then when the tank cycles, in larger tanks, you can add 2-3 fish per week until you reach capacity of your tank. No tablets should be needed to stabilize the water in a freshwater tank that is cycled. I never add any type of chemicals to my tanks other than the water conditioner like StressCoat or AquaSafe.

In a 150 gallon tank, I put about 15 Zebra Danios in there and let them cycle the tank for about a month, then all is usually fine. Can't help you with the frogs, I've never kept any.

If you currently have 2 Algae Eaters and 5 frogs in the tank and appear fine, leave it alone for a few weeks other than doing a 25% weekly water change. Then try adding a few small fish a week. Even when the tank is cycled, you never want to add too many fish at once because the filter needs to adjust to the bioload.

And about the twit at the fish store....I would avoid further purchases from that store. It sounds to me like SHE is the one who isn't a fish person.

Hope this helps you, good luck.

Richard