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All great advice so far. I would like to emphasize a few points. First off...you tank has not cycled completely. The biggest mistake folks new to the hobby make is adding too many fish too quickly. I cannot stress enough the importance of allowing your tank to experience a good solid cycle PRIOR to adding livestock. If you do not, you will find yourself in the middle of a never-ending game of "catch-up" trying to keep parameters at acceptable levels. I say acceptable because ideal parameters will be hard to achieve at this point. I highly suggest you return all of the livestock to the LFS
and let your tank cycle properly and completely before adding anything.
As mentioned, the addition of lots more LR
will be very beneficial both now and down the road. Anywhere from 80-100lbs total should be a good goal to shoot for. You are making very common mistakes but the good news is that you are not too far into things that you cannot recover. It is just going to take a bit more time. Slowing down now will save you big time heartache, money and time in the long run.