Need help with water quality FAST!!

Hello, I need help fast please. My fish are not dying, but i am afraid if I don't fix things soon they will. I have had my tanks for about 5 months now. i did properly cycle them when i set them up, & I also used this product called "cycle" to add additional beneficial bacteria. I test my water twice a week, clean my filters in tank water every other week, & do water changes/vaccum my gravel once a month. I used to use the PH & Ammonia test kit with the vials that you collected tank water in & used drops. My core fish that I have had since the beginning seems fine, but whenever I try to add anything new (including algea eaters) they die within 24 hours. I recently did some research & realized that my kit does not test for Nitrates or Nitrites. So i bought a kit that uses dip-sticks that tests for all, & both were off the charts bad for all 4 of my tanks. my water is also very hard, very low alkaline, & I have a very hard time with my PH, & no matter how many times a day I add PH up i can't seem to get it over 6.2. My ammonia is also always ready 6 or 8. We do not over feed the fish, & I don't think the tanks are overcrowded. The tanks all have aeration. I use Ammo Lock, Stress Zyme, Salt, Stress Coat, Cycle, another product made by cycle to breakdown the waste, & PH up, and now I also started using Nitraban, but nothing seems to be changing. How can i fix all of this, what is my problem, what am i doing wrong? Please help

5 gal - 1 male, 1 female molly
10-gal - 2 female, 1 male swordtail
10-gal - 2 male, 4 female, 20+ juvenile fancy guppies, & 1 algea eater
20 gal - 2 gold, 1 opaline, 1 blue gourami, 1 black neon tetra

 

How does your make up water test out ? Alos you have any decorations with in this tank like a fake rock or anything that could leech out also are you on local public water or a private well ?

 

What water are you using when you do your water changes? What are your parameters? Those 6 in 1 dip testers are garbage.

 

local water, I have plastic plants, castles, & caves, & the like all purchased from the pet store in the aquarium aisle (i was to afraid to use anything not marked specifically for an aquarium). Plus of course gravel. My water straight from the tap reads minimal ammonia, & 6.8PH, & before I ever added my first fish I had the tanks at 0 Amonia, & 7.0 PH for the livebearers, & 6.6PH for the gouramis. I do also have 1 live plant in the tank with the guppies.

 

I use tap water during my water changes, but treat it with water conditioner, etc first. What different test kits do u recommend that are the most accurate?

 

Are you on well or city water? If on city water, are you using a dechlorinator?

 

I am on city water, & do use a water conditioner/ dechlorinator...my chlorine levels are 0

 

have you tested for copper?

 

how do I test for copper?

 

Try to get a fresh water test kit that comes complete or go to your LFS and ask them to test your water, both in your tank and the tap water after you use the water conditioner/ dechlorinator. I personaly dont like using city water for anything, except I have a r/o unit for my make up water.