First Post....Fish and Plants Dying

My search function isn't working so forgive me if this is a reposted topic.

I have a 46 gallon tank that i have cycled and everything tested well.

Bought several varieties of plants (aquarium expert didn't inform they'd need huge amounts of light). I've had everything in for about 2-3 weeks and the plants are all looking horrible, leaves falling off right and left. I figured this is due to the bad lighting (20 watt 1 bulb hood standard). I've added two add-a-lights to get that to 60 watts but was told that's still not nearly enough. I'm resigned to the fact my $60 worth of plants are gone and will restart with java ferns and moss.

Now onto the real issue i'm having.....the fish. I have/had about 20 fish total (including 10 neon tetras). I'm now down to 5 tetras and of my 8 guppies 4 are left. I keep testing the water and everything is good except one thing....hardness. i'm at between 25-450 ppm. I was told adding some salt could help but then read that will kill the plants. Please let me know what i'm doing wrong?? I love my new tank but can't seem to get it going. Anything simple i can do to make the water softer and do you think that's the reason i'm losing my fish? I've done 1/3rd water changes once a week for the past 2 weeks and still nothing. Thanks!!! and sorry for the long post. I'm glad i found this place.

didy said:

What are you adding to your water when you do a partial water change?

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aqua plus tap water conditioner. i've been following the directions exactly but it makes no mention of softening the water........just de-chlorinating.

PH is around 6.8-7
Alkalinity is around 80
Hardness is i'd guess 350 or more!
Nitrite 0
Nitrate 40

I've only been removing the leaves that are floating at the top. Most of the plant are in bad shape, should i just take them out for good?

I cycled the tank with 5 tiger barbs that didn't make it after about 1 1/2 weeks. Then it sat, i had it tested at the shop and he said my Nitrate or Nitrite (can't remember which one) was obviously off and that was why they died. He then said i don't need to add more fish, that the "cycling" had taken place and now just do a water change and test again, once it's good i can add fish and plants.

I have gravel vacumed where i could when i did the water changes. Plants make it tricky as i'm sure you all know.

I have noticed the past few days i'm now getting lots of algae growth.

I really hope i can solve this as i don't want to give up on a new hobby.

no i guess my little strips dont test for ammonia.

well i can tell when some of them aren't doing well, then the next morning they are belly up or half eaten.

I'd say the tank sat empty (no fish) for 2 weeks after the cycle fish died.

****. i just did it less than 5 days ago. almost half the water. i had a little 10 gallon tank as a kid and don't ever remember having this kind of trouble.

so should i remove my plants that look bad and just chunk them? i have a piece of drift wood on order that i'm going to put in and attach java moss to.