clouding water HELLLLP!!!

[Carri]

Ok my 15 Gallon is beautiful...nooooo problems, My 55 on the other hand keeps clouding up and then turns nasty green(ended up with 2 getting septicimia(all better). Added an undergravel filtration system and it seemed to be doin good...but I noticed this afternoon, Its starting to cloud up...UGH!! Im about broke trying to fix this...What can I do? B4 the UG filter, I treated with algae killing chemicals cuz someone said it was algea plumes. I also tried another water clearing chemical that the pet store recommended. The pet store said water was acidic and theres nothing I can do but continuous tank changes(and dont understand cuz other tank is fine I took water from both). I am at a loss I love my fish

 

[GoldfishNewbie]

what fish are in it? it may be overstocked... Ive only dealt with bacteria blooms, which when it clouds it turns white-ish, but Im fairly certain doing 50% pwc's a day should help for now. did you add anything new to the tank?
I suggest you buy yourself an api master test kit (liquid) and you can see whats wrong, they're more accurate than whatever the pet store will tell you. You can then test your ammonia, nitrItes, and nitrAtes... as well as the ph.
I know its more expensive than the other test kits, but when your dealing with issues like this, you want the best. so please reply with more info about your water params, as well as what fish are in :O
But right now Id do an immediate 75% water change, and then everyday for the next few weeks do 50%

 

[Carri]

It has a 5 inch upside down catfish, a 7 inch goldfish, a 4 inch calico shubunkin and one 3 inch grommie(not sure of the spelling). I havent been able to get the master test kit yet ( just spent every penny we had saved buying the 55 gallon and the the filters and then the undergravel filter and chemicals) I do have the liquid PH test which is reading 6.8-7.0...My last water change was done LAST sunday and it was a complete(to put the U.G. filter in) Sadly I had another Grommie which I mentioned in my last post which died this afternoon I treated it for septicimia over the week in a hospital tank and thought it was doing better The other fish seem fine so far no symptoms of anything. When I do water changes the pet store told me to treat the new water with conditioner and a "clear water" product at the same time...I have not done so yet ( chemicals scare me, seen them do HORRIBLE things to a friends fish) I usually do the tap water conditioner but not with the clear water stuff. Like I said b4 my 15 gallon is PERFECT hasnt needed anything...other then a fat fancy with a swim bladder issue It is beautiful and the fish are happy. I don't understand how I can use the same water and the same conditioner and have such different results..its frustrating and my husband says if my fish die he's getting a SNAKE!! AHHHH!!!