My 10 gallon tank has been getting cloudier by the day. I just returned from the pet store, they told me to use ammo lock. Is it safe to put this in the tank with my goldfish in it, or should I remove them and do a complete water change and treat the new water first , then put my fish back in the tank?

This is my section on cloudy water:
http://www.fishpondinfo.com/plants/algaeinfo.htm#cloudy

It is most likely a bacterial bloom. Read about the nitrogen cycle here:
http://www.fishpondinfo.com/chem.htm

When you have a new tank and a lot of fish, the bacteria will try to grow quickly. Without a substrate (biological filter that's large enough), the bacteria grow right in the water. You should test the ammonia and nitrite levels to see how they're doing. Ammo-lock is only used if you have high ammonia (as one way to deal with it). I suggest doing 50% water changes every few days and adding good bacteria. Doing a 100% water change is very stressful and should only be done in emergencies. How many goldfish do you have in there, how big are they, and how long has the tank been set up? You will have a much easier time with a larger tank. If the tank has too much fish mass in it, it may never become clear. Hopefully you'll get some ideas from my pages from the links above. I've had tanks go cloudy a few times and with water changes and good bacteria, they all eventually recovered. It may take a few weeks. Hope it clears soon!

Oh, I just saw in your sub-topic that you say the test for ammonia reads as toxic. I would absolutely do a 50% water change and add some Ammo-lock. If you do a 100% water change, the ammonia should be near zero but without proper biological filtration (good bacteria), the ammonia will sky rocket back up within a day or two. So, I would stick to daily 50% water changes, adding good bacteria, and maybe Ammo-lock some. You want the good bacteria to consume that ammonia and multiply so at least short term, there may have to be some readable ammonia (you don't always want to lock it up). My water chemistry page has advise on dealing with high ammonia levels.

I have five goldfish and one algae eater. They're actually my daughter's fish, I wish she would have told me she wanted a fish tank before she went out and purchased it. She had all these fish in a tiny 2 or 3 gallon tank when she brought them home. My bf had fish years ago and he immediately went out and bought the ten gallon tank, pump, filter, bubble stone and other supplies he knew she'd need.

They've been in the larger tank since last Monday, today is day seven.

We set H2O aside last night and added a tap water conditioner ( Aqua Plus) to remove the chlorine & chloramine.

We plan on doing the 50% water change this afternoon.

*I still need to know if it's safe to add the AMMO LOCK with the fish still in the tank.

Thank you for your advice! :)

Yes, you can add Ammo-Lock with the fish in the tank. Just follow the directions. Your tank is new and super crowded. So, an ammonia spike and cloudy water is to be expected. Even five young goldfish need more like 20-30 gallons. Goldfish can grow to about 14" long (mine are anyway). If the "algae eater" is a pleco, it can grow to over a foot as well. If it's a Chinese algae eater, it may chase the goldfish around. If money weren't a concern, I would say to get a 55 gallon tank or so but you may have to make due with what you have. It may require 50% water changes every few days to keep the fish alive. I hope things work out!